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| Assessing a coach to purchase - 12 volt system [message #211892] |
Sat, 22 June 2013 18:14  |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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I have been reading voraciously across this forum, the suppliers, and the club sites for the last two weeks as I am deciding if I want to buy a neighbor's 1975 Eleganza. The community definitely is a selling point. It has been sitting, unmoved, unstarted, un-anything for nearly nine years. Current owner has let me work on it/assess. Several good things, several things need work (and money). Got generator started thanks to hot wire/priming trick from a web site. Old tires on 16.5 - either drop 3 grand total with aluminum upgrades or $1300 on Firestone TransForce seem to be only options there. Rebuilt engine fired right up after priming from passenger seat - because the front gas tank has a leak, so both tanks would need to be pulled and sealed. I only ran the 455 a minute or two at a time, as the coolant was pressing out from the overflow tank up front indicating something stopped up. Could post a LONG piece with what I have done, learned and found so far, but here is the biggest unknown so far...
Current owner stopped messing with it years ago because the batteries would come up dead overnight. I have been testing components and shore power ran 12 volt house fine. A battery hooked up by the generator ran 12 volt house fine. Here is where it gets weird - I took the battery out of generator box and moved it to the engine bay. I put negative lead on battery. When I put positive lead on battery, I heard the roof fan that was running from shore power (converter) stop. Thought I blew a fuse, but apparently not. Unless it was an amazing coincidence, it seems that the hot lead in the engine bay acted like a short which overloaded the converter which still buzzes, but doesn't put out 12v. These systems should be completely isolated except through the boost switch. However - I have a finned blue box above the solenoid in engine bay that has a hot lead to the rear battery connection, a hot lead to the engine battery connection, and one that goes into a wiring harness that I can't deduce purpose. And another clue/oddity - the radio in dash only comes on when I push the battery boost switch. So...diagnosing electrical is tough anyway, but ideas or things to test are most appreciated. What is the blue box? An isolator/insulator/combiner - I have read all these terms and how would I test it?
Many thanks!
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Assessing a coach to purchase - 12 volt system [message #211896 is a reply to message #211894] |
Sat, 22 June 2013 19:39  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Suggest disconnecting the house battery from the system, and seeing if the engine side works as expected.
Radio running only when boost switch is engaged indicates a mixed wiring harness. Need to find the mis-wired section, and restore it to OEM. If he batteries are going flat overnight, I would expect a short somewhere.
If the 12v converter is still the OEM buzz box, it may be defective internally. Easier and better to replace it with a modern 12v charger. Progressive Dynamics, Iota, Xantex, etc are good choices. Do not need a bigger than 45 amp model.
Blue finned box is a battery isolator. Purpose is to isolate the engine battery and the house battery from each other. Center lead going into harness is to the alternator. The boost switch temporarily combines the two batteries to allow an almost dead engine battery to be assisted by the house battery to start the engine. Many have replaced this with a combiner. You can check the function of the isolator with a multimeter by testing the diodes, going from the center post to either end post. They both should read as diodes. If either is open or shorted, the isolator has failed.
Lots of very good help on this net. Only stupid questions are those not asked. We all started with limited knowledge, but this group will fill in all the blanks.
Please turn on P.M. Function so private e-mail can be sent to you.
Please indicate where you are located in your signature file. Help may be around the corner.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: Assessing a coach to purchase - 12 volt system [message #211897 is a reply to message #211892] |
Sat, 22 June 2013 19:43 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Read what Tilerpep wrote on Sat, 22 June 2013 19:14
It is way too long and involved to quote.
He is attempting to clear issues so he can buy a neighbor's 1975 Eleganza.
Tiler,
Please enter a sigfile that has a name, coach type and geographic reference so other that might help know the essentials.
A lot of what you have written does not initially make sense.
The batteries going dead over night is probably an easy fix, the trick will be finding it. In the mean time, just be sure to disconnect the batteries every time you turn around.
The finned blue box is an "isolator". It contains to big diodes and allows the main engine alternator to charge both the house and start batteries. If you have a meter (if you don't get a cheapo from Hazard Fright), label (LABEL) all three cables and disconnect them. The center terminal is a common and should be going to alternator output. On the resistance scale (Ω) you should get a reading with with the probes one way between the common and both ends and nothing when you reverse the probes and do the same. If that is what you get, then that is good. If you get nothing both ways or something both ways, the isolator is dead.
The buzzbox that was running the fan could have quit for a variety of reasons, but we won't start that now. Before you get too far, pop the breaker so is stops buzzing and pull all the house fuses. Power it up again and see if it make 13+ volts unloaded. If it does not, it is dead and that is now loss.
Bookmark http://www.bdub.net/GMCLinks.html
You can there - actually http://www.bdub.net/wirediagrams/ and download wiring diagrams.
As the coach is an Eleganza (GMC fit) there is a pretty good chance that the wiring will be as designed but you will have to watch out for well meaning changes made in the last 35 years.
You have a good start, keep at it and come back when you can ask more questions.
Someone will be here to answer.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Assessing a coach to purchase - 12 volt system [message #211900 is a reply to message #211892] |
Sat, 22 June 2013 20:07 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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I would get it.And I bet its really got not too many problems.
12v stuff and shore power stuff,just a little confused.16.5 tires are cheap still.9 years is not that long.I bet its just the fuel lines and e-pump cross and vents and such. Unless snow?
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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| Re: Assessing a coach to purchase - 12 volt system [message #211904 is a reply to message #211892] |
Sat, 22 June 2013 21:25 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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The electrical stuff should be not that expensive, just has to be worked through in a logical maner. Spewing radiator would be my first concern. Posdible head gasket. But could be simple bad radiator cap. They are a rubber item and therefore should be replaced at 5 years or so. It 's probably 35.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Assessing a coach to purchase - 12 volt system [message #211909 is a reply to message #211892] |
Sat, 22 June 2013 23:15 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Senior Member |
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Thanks for the great replies. Tomorrow I can test isolator and start with a radiator cap.
What is protocol for asking questions? I'm afraid if I start a new thread for each it will be loopy. Like:
A. The light/speaker over driver and passenger seats have three way switch - light on, light off, and what?
B. I tried to get the buzzbox out to test, the ground is so far back I can't get it out to test without cutting? alternatives?
C. Is there a web write up to remove dash, I need to track a bunch of non-oem wires
D. This coach has a robust ball style tow hitch welded to the frame. To consider a toad it seems I need the receiver style or use a tow dolly with the ball. Are these the only good options? Considering towing a 2000 jetta on a dolly but would rather put a manual tranny paseo or something small four down. Current owner put in a 3.42 drive.
E. Without said receiver hitch, where can I carry bicycles?
Enough for tonight. Thanks again.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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| Re: Assessing a coach to purchase - 12 volt system [message #211915 is a reply to message #211892] |
Sun, 23 June 2013 00:15 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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There are some spare tire mounted bike carriers that don't require a hitch receiver. If you are using the hitch also, depending on how many bikes you have, there may be an issue with them getting tangled up with whatever you are towing.
Here is one I have been eyeing on Amazon, that one of the other GMC'ers suggested. (danger, obscenely long link coming . . .)
< http://www.amazon.com/Allen-Sports-Deluxe-3-Bike-Spare/dp/B000ELSSWW/ref=wl_it_dp_o_pd_nS_nC?ie=UTF8&colid=1KAL1EWCX421X&coliid=I3B8R4B0KFXCJ9>
You've gotten a lot of good electrical tips already. If the isolator is really old, there is a good chance it is bad, mine was, when I got my coach. Probably all rv places and a fair number of auto parts stores carry them. If your engine starting (chassis) battery was quite low in charge, hitting the boost switch could pull the voltage down on the house side enough to make house things slow or stop. Particularly if the house battery was also very low and mainly being kept up to voltage by the original buzz box.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: [GMCnet] Assessing a coach to purchase - 12 volt system [message #211916 is a reply to message #211915] |
Sun, 23 June 2013 00:40 |
mickeysss
Messages: 1476
Registered: January 2012
Karma: 0
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make all grounds bright.
m. ca. pb77
In la they would steal all the bikes and bike rack if strapped on. Need to be locked on.
On Jun 22, 2013, at 10:15 PM, Craig Lechowicz wrote:
>
>
> There are some spare tire mounted bike carriers that don't require a hitch receiver. If you are using the hitch also, depending on how many bikes you have, there may be an issue with them getting tangled up with whatever you are towing.
>
> Here is one I have been eyeing on Amazon, that one of the other GMC'ers suggested. (danger, obscenely long link coming . . .)
>
> < http://www.amazon.com/Allen-Sports-Deluxe-3-Bike-Spare/dp/B000ELSSWW/ref=wl_it_dp_o_pd_nS_nC?ie=UTF8&colid=1KAL1EWCX421X&coliid=I3B8R4B0KFXCJ9>
>
> You've gotten a lot of good electrical tips already. If the isolator is really old, there is a good chance it is bad, mine was, when I got my coach. Probably all rv places and a fair number of auto parts stores carry them. If your engine starting (chassis) battery was quite low in charge, hitting the boost switch could pull the voltage down on the house side enough to make house things slow or stop. Particularly if the house battery was also very low and mainly being kept up to voltage by the original buzz box.
> --
> Craig Lechowicz
> '77 Kingsley, Waterford, MI
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| Re: [GMCnet] Assessing a coach to purchase - 12 volt system [message #211917 is a reply to message #211909] |
Sun, 23 June 2013 00:45 |
mickeysss
Messages: 1476
Registered: January 2012
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ragusa ladder bike racks are pretty good. attaches to the ladder in the rear, also putting them in front bumper area is an idea.
m :-) ca. pb 77
On Jun 22, 2013, at 9:15 PM, Tyler wrote:
>
>
> Thanks for the great replies. Tomorrow I can test isolator and start with a radiator cap.
>
> What is protocol for asking questions? I'm afraid if I start a new thread for each it will be loopy. Like:
> A. The light/speaker over driver and passenger seats have three way switch - light on, light off, and what?
> B. I tried to get the buzzbox out to test, the ground is so far back I can't get it out to test without cutting? alternatives?
> C. Is there a web write up to remove dash, I need to track a bunch of non-oem wires
> D. This coach has a robust ball style tow hitch welded to the frame. To consider a toad it seems I need the receiver style or use a tow dolly with the ball. Are these the only good options? Considering towing a 2000 jetta on a dolly but would rather put a manual tranny paseo or something small four down. Current owner put in a 3.42 drive.
> E. Without said receiver hitch, where can I carry bicycles?
>
> Enough for tonight. Thanks again.
> --
> Potential owner
> 1975 Eleganza
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> Unsubscribe or Change List Options:
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| Re: Assessing a coach to purchase - 12 volt system [message #211939 is a reply to message #211909] |
Sun, 23 June 2013 08:36 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Tilerpep wrote on Sun, 23 June 2013 00:15 |
Thanks for the great replies. Tomorrow I can test isolator and start with a radiator cap.
What is protocol for asking questions? I'm afraid if I start a new thread for each it will be loopy. Like:
A. The light/speaker over driver and passenger seats have three way switch - light on, light off, and what?
B. I tried to get the buzzbox out to test, the ground is so far back I can't get it out to test without cutting? alternatives?
C. Is there a web write up to remove dash, I need to track a bunch of non-oem wires
D. This coach has a robust ball style tow hitch welded to the frame. To consider a toad it seems I need the receiver style or use a tow dolly with the ball. Are these the only good options? Considering towing a 2000 jetta on a dolly but would rather put a manual tranny paseo or something small four down. Current owner put in a 3.42 drive.
E. Without said receiver hitch, where can I carry bicycles?
Enough for tonight. Thanks again.
|
Tiler,
Answers for:
A - On, off and as courtesy light with the door
B - Disconnect the ground at the Buzz box. (They put the ground on the frame before they moved the interior into place.)
C - Get a the coach wiring diagram and a label maker. If it isn't on the OEM diagram - label it - maybe label it anyway.
D - There are numerous towbar manufactures. Most make one for a ball hitch. Check that the Paseo can be towed 4-down, some manuals cannot.
E - Can't help you there, mine fold up and store under the dinette.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Assessing a coach to purchase - 12 volt system [message #211947 is a reply to message #211939] |
Sun, 23 June 2013 10:11 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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We have a receiver hitch on our towd too. The bicycle rack goes in that one. You can kind of see it in this pic.
http://www.gmcmhphotos.com/photos/trips/p42501-along-the-101.html
If you're flat towing, or using a dolly, the hitch you have MAY be sufficient. A heavier receiver hitch would be more necessary for towing a trailer with the required amount of tongue weight on the hitch.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: Assessing a coach to purchase - 12 volt system [message #211959 is a reply to message #211947] |
Sun, 23 June 2013 11:29 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Do not spend any time or money on buzz box. It is very old technology and will kill batteries. Makes a good bench top 12v power supply, but much better choices for a charger exist.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] Assessing a coach to purchase - 12 volt system [message #211968 is a reply to message #211960] |
Sun, 23 June 2013 12:22 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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| Tilerpep wrote on Sun, 23 June 2013 09:34 |
I have not seen anything about adding a receiver hitch to the front of the GMC's - staying with the bike rack idea rather than any sort of big loads. Anyone done it or find something on the web?
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another way to install a front hitch is too remove the front license plate cut a square hole in the bumper and mount a square tow unit too the bumper bracket it will support the light load of a bicycle and the bumper shocks won't be compromised. I did this for another way to launch a boat. Then put a trailer tow cap behind the license plate and it can be reinstalled to the bumper with nothing hanging down from the bumper.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: Assessing a coach to purchase - 12 volt system [message #211973 is a reply to message #211892] |
Sun, 23 June 2013 13:59 |
Tilerpep
Messages: 404
Registered: June 2013
Location: Raleigh, NC
Karma: 7
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Senior Member |
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You guys are awesome on the ideas and info - I am a newbie with a welder (to actually build a custom hitch), but I will look at mounting some receivers for bike mounts separate from the towing idea. Ladder racks and spare tire mounts give some options.
Next RV question (I have driven cross country round trip four times, one way three additional times: two with a popup, and the others with various rigs, never a motorhome.) Can I service the roof units with my car AC gauge set and refill cans? Are there fittings up there or is it a closed system? I would guess these old air units don't have 134, and I have seen some people talking about Duracool - is that an option to service them?
The awning has sun damage on the first foot - are there sprays or sealers or something that I can stop the degradation? My first thought was cut that first roll off and bring fresher fabric to coach wall to mount, but that looks as complicated or more than a new install. Ideas?
Many thanks.
1975 Glenbrook, 1978 Royale rear bath
Raleigh, NC
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