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| TOWD Lighting Isolation [message #271456] |
Sun, 08 February 2015 23:21  |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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There are many ways that are, and have been, used to provide the required lighting for a towed vehicle. In most cases, people are happy with the results. There are, of course, some that are not as successful as they could be. It drives me crazy to follow a trailer, towed vehicle, or even a RV or Car that has poor lighting. It's just not necissary.
I would like to propose another way to wire a TOWD for Signal Lighting. I've used it very successfully and customers have been very happy.
This procedure will light the TOWD through the stock fixtures without having to drill holes in the fixtures and trying to place a second light bulb in the proper place in the fixture.(Impossible because the stock bulb is already in the proper place) It powers the bulbs with full available voltage with no voltage loss due to diodes or small gauge wiring. It actually is less expensive and not that much more work. You are not required to place external or additional lighting fixtures on the TOWD. Hitched up or driving, there is no changes needed to the TOWD. It is fully automatic. The towed vehicle looks and operates just like stock. And Best of All. The lights are bright, clear, and work properly!!!
In order to tow the vehicle, the Dash computer needs to be disabled so I also provide a procedure to make removing the fuse manually unnecissary.
I've created an album with the procedure I used when wireing my 96 Sunfire Convertible that I tow behind the Coach. You can find it at the following address.
http://www.gmcmhphotos.com/photos/towd-96-pontiac-towing-details/p57192-towd-tail-lights-isolation-network.html
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271500 is a reply to message #271456] |
Mon, 09 February 2015 11:40  |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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John Heslinga wrote on Sun, 08 February 2015 21:21...
I would like to propose another way to wire a TOWD for Signal Lighting. I've used it very successfully ...
... I've created an album with the procedure I used when wireing my 96 Sunfire Convertible that I tow behind the Coach. You can find it at the following address.
http://www.gmcmhphotos.com/photos/towd-96-pontiac-towing-details/p57192-towd-tail-lights-isolation-network.html
John,
I like to concept. I might incorporate a variation in the Sidekick towd that I am building out of a basket case of parts. I have the wiring harness(s) out and in a box. I can (and will) modify it for towd use before reinstalling it giving my modifications an "as built" look and feel.
Looking over the diagram and thinking in my minds eye of how it works, I have a question. But first let me make sure I have the operation correct.
Each relay is activated with the input from the coach. When a particular light on the towd is needed to be lit, the 12v signal from the coach will energize that particular isolation relay. Disconnecting the car input and using the 12v input from the coach to light the desired bulb. Correct?
So far so good, but note each relay operates separately, independent of the other inputs from the coach.
I am assuming that the car tail light bulbs you are using are the brake lights and you have a towd braking system that activates the brakes on the car when needed.
Now my question:
What is the behaviour of the car tail lights when slowing down (using the brakes) when using a turn signal?
Reason for my question:
From my look at the diagram, it would seem that the tail lights on the towd would be on steady, Indicating to anyone following you, braking but not turning.
The reason I think this is when the blinking side isolation relay would de-energize everytime the coach light goes out... allowing the power from the car brake light circuit to light the bulb. (Brakes applied by the towd brake system) You might get a flicker as the power switches from the coach and the car brake system, but it wouldn't blink.
One possible solution is to use diodes to "gang" the isolation relays together. This way ANY input from the coach isolates ALL circuits from the car systems until ALL inputs from the coach are removed. Or at the minimum, gang together the two brake/turn light isolation relays.
If your are using the car rear TURN signals as towd lights (if red) or not using a towd brake system... you system should be just fine.... Near as I can figure from the diagram and thinking. 
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: TOWD Lighting Isolation [message #271504 is a reply to message #271456] |
Mon, 09 February 2015 12:08 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Not to take away from your set up John. I have been towing my Toyota truck for more then 10 years with diode packs with no issues. Last year I installed a different aux brake unit and needed a 7 wire plug. I had an intermittent electrical short that would sometimes blow the fuse every time I checked it out it was fine. The diodes just made it harder to trouble shoot. So I removed them and added an extra bulb assembly to make it a simple circuit with only the coach wires in the system it turned out a tiny screw in the plug was the cause of the intermittent short. In my opinion simple is better especially when you are on the road.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: TOWD Lighting Isolation [message #271512 is a reply to message #271456] |
Mon, 09 February 2015 14:16 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Mike:
Your interpretation of the system is correct. In this case (96 Pontiac convertible ) the tail lights are combination lights without separated signal lights. But it has a high mount brake light in the spoiler. It is also using a US Gear braking controller as the Auxiliary Brake Application system.
The US Gear controller module is directly wired into the vehicle and disables the brake lights at the brake light switch. The vehicle brake lights are not applied if the system is applying the brakes. The brake and signal lights are controlled by the Coach. Following drivers would see light operation just like they expect.
However: In a combined tail light system the brake light power goes through the signal light switch to condition it for the directional signal fixtures. Another wire is sent directly to the high mount light, unconditioned. I wire the disable circuit from the US Gear controller only into the signal light switch leg. US Gear Instructions do not say anything about this. This way the High Mount Light is controlled by the US Gear Brake Controller and the tail lights are controlled by the coach.
Changing the network wiring slightly by using diodes into the relay control circuits is an ideal way to activate all relays at once if you are not using a brake system such as the US Gear. I do the same thing and should have noted that change. (I only have these pictures ) This is another problem with using RV Diodes or additional light bulbs as the isolation strategy. The "Pedal Pusher" brake controllers will override the coach signals and the problems you state start to show themselves. (Confusing light signalling) RV Diodes and Additional bulbs work as "and/or" logic devices. A signal on either input will result as an output (Light On)
Tonight sometime I'll show that change in another circuit diagram and upload it.
I have to say though, I am really happy using the US Gear Brake System. I never have to do anything to hitch up and go, or unhitch and go. It is all built in, plug and play, and automatic. It has a vacuum pump so the vehicle power brakes work, it keeps the battery charged, and I don't have to deal with a big box in the drivers foot space. I'll upload a few pictures of that installation too if you are intetested.
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271522 is a reply to message #271456] |
Mon, 09 February 2015 15:45 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Roy:
I'm sure you have been happy with your Toyota Towd system. My intent is simply to show another strategy to handle wiring of a towed vehicle so that the message it sends to drivers following you, are clear and intentional. Many RVers use the strategy you describe, to connect their towds. What I'm describing is really no more complex than any other strategy.
You know this already, but I will say it anyway to make things clear to all who are reading who do not, and to help put my comments in context. (Just like my students in my classes. Not Everyone understands as well as you)
Unfortunately,operating two vehicles in tandem is not a simple machine. It is two complex systems, sometimes quite different in how they work, that need to cooperate with each other and operate as one. Different combinations of models and types need different strategies. A properly equiped TOWD will have its own auxiliary braking system, electrical system, Lighting system, and operational logic systems including multiple computers operating in networks.
Interfacing the two systems need to represent a complexity that will appropriately match the outcome desired and be robust enough to be dependable. (Therefore I understand your comments about making things simple).
However: if the outcome is not appropriate, then the stratigy needs to change. And sometimes that means more complexity. (Not really a surprise right?)
Let's assume: your Toyota dingy has a portable brake actuator that you place in the drivers floor pan and clamp to the brake pedal. (Some of these are self controlled using an accelerometer) You are using a totally independent lighting system on which you have extra light bulbs installed in the rear fixtures. And lets add a situation: you are approaching an intersection with signal lights on and braking hard enough to activate the braking unit.
Here is my interpretation of the system.
The extra signal light bulb is being flashed by the coach. It is not in the ideal location for the reflector in the fixture, but it is bright enough to see it flashing with nothing else on. The brake actuator begins to put pressure on the brake pedal which actuates the brake light switch in the Toyota. (The Brake Circuit in the Toyota is not through the Ignition switch) Now the Toyota turns on the brake lights in the same fixture. Because the Toyoa Bulb is in the ideal position. It creates a brighter fixture illumination. This cancels out the flashing coach bulb and basicly outshines and disables the signal light. At least it will be unclear if the fixture is flashing or not.
To me: this creates a confusing and unclear indication to the driver behind you of your intent. (Not as safe as it could be)
RV Diodes do the same type of thing. Any input to one side of the diode will apply power to the bulb. Therefore the bulb will stay lit full time if one input is flashing and the other in full on.
If your Happy with what you have, then it probably is working better than all this
Or Is It??
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271569 is a reply to message #271522] |
Tue, 10 February 2015 02:03 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Mike:
I had stated that I would update the isolation circuit so that it would disable any brake light input from the the TOWD.
Here is a change that I would suggest.
http://www.gmcmhphotos.com/photos/towd-96-pontiac-towing-details/p57203-disable-brake-lights.html
I added a power line to the network to make it more of an active network than passive. (and a minor added level of complexity too) There is a very simple and cheap electronic circuit to add to the network as well. The components should be available wherever electronic parts are sold. For my Pontiac this would not be a problem because the keyless entry module is in the trunk. But if power was not in the trunk an extra line from the front of the TOAD would be needed. (Not really a problem because your dragging Coach wiring through the car anyway). The Resistor and Capacitor values change the amount of time it takes before the relays release. You want about 2- 3 seconds. I'm not sure if those specs I put in will will be short enough. (I'll let those with more Karma than me calculate the exact figures needed.) I would do some trial and error to get what I wanted. These specs should be a place to start however.
The power and the electronic circuitry works like this: When a signal light pulse comes on ,it charges the capacitor and pulls in the two relays for the signal lights for the duration of the pulse and a few seconds after the pulse stops. During that time, the relays reject all signals coming from the TOWD. This allows the coach signal lights to flash normally.
If you want to run Brake lights in a vehicle with separate lights for brakes and signals. Changes have to be made again. The problem is that the Coach does not have an isolated brake signal so an adaptor would have to be make. I can do that too.
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271571 is a reply to message #271569] |
Tue, 10 February 2015 03:18 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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John,
It took me a while to figure out how what you added will work. I finally understand it.
What if you took your original diagram and just added added a capacitor across the two relay coils and a diode in series with the +12 feed to the two relay coils. That would eliminate the need to run the additional power wire to the circuit.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: TOWD Lighting Isolation [message #271604 is a reply to message #271571] |
Tue, 10 February 2015 09:31 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Ken Burton wrote on Tue, 10 February 2015 02:18John,
It took me a while to figure out how what you added will work. I finally understand it.
What if you took your original diagram and just added added a capacitor across the two relay coils and a diode in series with the +12 feed to the two relay coils. That would eliminate the need to run the additional power wire to the circuit.
KEN
Thanks for the input: these kinds of things can always use some tweaking. I thought about something like that too because it seemed like the quickest and straight forward. You can see the addition of the diodes are needed to combine the relays. However I suspected that powering two relays with enough voltage and current (power) to keep them latched for a few seconds takes a lot of capacitor that are not that commonly available. I also considered a double pole relay to decrease the power needed, but that meant finding one and adding to the difficulty of aquiring parts. I eventually felt that simply switching power (or ground) to the relays had a lot more leeway with experimentation, length of time the relays latch, and ease of component acquisition. The power is really not a problem because you are pulling wire anyway. (A very small gauge is really needed) However: That being said, Electronics gurus such as yourself would need to provide some calculations on how much capacitor is needed. (I could not convince myself last night what a foolproof value of capacitor would be needed)
But The real problem is using a flashing power supply, and in the scheme of things either way added about the same complexity. For interest sake, would you mind calculateing the value of capacitor we would need to satisfy the relays? I would also appreciate a calculation on the resiator and capacitor combination I'm using to get about 1 to 2 seconds latching.
Best Regards
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271612 is a reply to message #271573] |
Tue, 10 February 2015 10:35 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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mike miller wrote on Tue, 10 February 2015 03:13John,
9
I am not sure you need THAT much complexity.
How about this:
<http://www.gmcmhphotos.com/photos/data/5541/Isolation_Network_mjm.JPG>
I just added a pair of diodes just before the signal light isolation relays and connected the two relays to work together.
I also removed the back-up light from the diagram to clean up the diagram. Most users would not include them anyway.
Mike:
Thanks for looking over and evaluating my proposal.
Deleting the Reverse Component of the system and not having reverse lights is no problem and is matter of personal desires. In fact if reverse was not used, the 4th wire in the ribbon going to the rear of tbe TOWD can be used for the 12V supply. I simply adapted the diagram I originally presented. The fun part of this exercise is adapting these suggestions to your needs and desires. In this case even reverse lighting is emulated in the TOWD.
Regarding simply putting in diodes. I went to the drawing board with that in mind, and after thinking about it all, realized a condition where that would not be sufficient. So then the night got longer. The Coach turn signal is a flashing (pulsing) voltage and the coach brake is constant voltage. The only time the relays will stay fully latched is when the coach brakes are on. This would be fine if you were braking and signaling. Some TOWD braking systems allow them to be energized without the coach braking. (My US Gear allows hand control braking) Under this condition, the TOWD breaking signal will interfere and turn on the signal ligjt fixture everytime the signal light pulse releases the relays. I decided that i would allow the coach to be the overriding and priority information to the TOWD lighting system by forcing the relays to stay latched for over a second so the signal light has time to go through a flash cycle. I realize the TOWD independent braking will not be evident for this one second but very little deceleration really takes place if only the toad is braking. The signal light flashing is already an indication something is happening. The bottom line in my mind is ensure the Coach lighting is being perfectly emulated in the TOWD.
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271619 is a reply to message #271522] |
Tue, 10 February 2015 11:33 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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John I did have a Remington even brake at one time and I did utilize the Toyota brake switch circuit but I didn't see any advantage to this way of applying the brake lights unless the toad came loose from the coach . If this happened the Toyota would likely be going for a wild ride. I now have a brake vender system that a friend gave me for$100 I like it a lot better. I'm old so old school and simple works well for me. I'm sure your approach has more benefits but I like treating the toad like it is a simple trailer lighting system in case I need to correct a lighting problem in the middle of nowear I hate to hear what is wrong now and how long to fix it. For some of us married guys those words can raise the blood pressure. For you tech guys that like something a little extra that does more I'll bet that system is the ticket.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: TOWD Lighting Isolation [message #271631 is a reply to message #271619] |
Tue, 10 February 2015 14:58 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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roy1 wrote on Tue, 10 February 2015 10:33John I did have a Remington even brake at one time and I did utilize the Toyota brake switch circuit but I didn't see any advantage to this way of applying the brake lights unless the toad came loose from the coach . If this happened the Toyota would likely be going for a wild ride. I now have a brake vender system that a friend gave me for$100 I like it a lot better. I'm old so old school and simple works well for me. I'm sure your approach has more benefits but I like treating the toad like it is a simple trailer lighting system in case I need to correct a lighting problem in the middle of nowear I hate to hear what is wrong now and how long to fix it. For some of us married guys those words can raise the blood pressure. For you tech guys that like something a little extra that does more I'll bet that system is the ticket.
ROY.
Cool. Thank you for your comments. I get it man!! You need to enjoy your coach by using it not fixing it. If something is working pretty well, why open up a can of worms when it is not really necessary. I'm really with you on that.
I know you get it, but I'll say it anyway. I was proposing a suggested procedure for those that would like to use if they start a new installation. I wanted to share the procedure that I use that is not much more work, and less cost than some of the more traditial methods. It does however: require more understanding of the systems involved and requires some more electrical skills than some owners have. Thats OK. Systems that are already in place in a successful manner should stay there. Some of the shortcommings of the other systems can be overcome without rebuilding and we could discuss those too.
I'm sure that if I were inclined, I could make a BLACKBOX Module and sell it to people who need that kind of help. There is certainly a big RV market who could take advantage of such a box. That would also make this project more palitable to some owners. However: It would still be only one more option to choose. There still would be discussions about the differences. That's cool too!!
Each TOWD / coach combination is different and each owner has different expectations for their application. I've worked with many customers and their vehicle needs to know there are many differing priorities and desires.
Getting things and doing things just because they are cool would seem silly on the surface however there are many owners who work that way. All the power and prestige to them. I also understand that being on a pension or getting older (I Am) and having other important people in our families and lives take precidance over the coach. We don't need to do everything that is proposed here. we choose.
The bottom line for me is for us all to enjoy our coaches in whatever way is right for you. Thank goodness all of our coaches are different. It makes being involved with them, so very interesting. Mine is my hobby and I can't thank you all enough for sharing your ideas!!!
Like many of you, I choose and adapt those ideas to suit my needs and desires. I embrace and fully agree with some and partially or wholly dismiss others. Some are Safe and some,I feel, are downright unsafe or dangerous . We have to take any advice with wisdom.
LET'S ALL HAVE FUN !!!
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: TOWD Lighting Isolation [message #271635 is a reply to message #271456] |
Tue, 10 February 2015 15:45 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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That's a nice design which will result in the same lighting as the toad alone. For me, however, it adds both active components and many more connections. In that failure modes are first connectors, second capacitors, and third active components, I'm gonna stick with the simplicity of a pair of dual filament bulbs hung in the T/L assemblies of the Mouse and seperate wiring. I took a different approach with the Toadstone (diesel VW Jetta). Since VW pretty much disconnects everything when the ignition and light switches are off, I simply connected the harness to the parking lights on each side and got excellent results.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: TOWD Lighting Isolation [message #271665 is a reply to message #271604] |
Tue, 10 February 2015 22:17 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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John. I have a bunch of those relays I do not know how I would calculate the cap size because it takes less voltage to hold the relays in than it originally took to energize them. So, I'll dig around in my junk box and try to find some caps to test with.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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