| [GMCnet] 3rd break light [message #200632] |
Mon, 04 March 2013 20:36  |
larry erd
Messages: 132
Registered: August 2010
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I am hooking up my new 3rd break light, do I have to run a new wire from
the light
to the front to tie into the brake switch in front of the turn signal
switch? Or is there
a way to use diodes in the back? Could I use the extra blue wire if I have
one?
Larry Erd
77 ex Kingsley
Getting ready for our maiden trip
to Dothan
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| Re: [GMCnet] 3rd break light [message #200633 is a reply to message #200632] |
Mon, 04 March 2013 20:39  |
sgltrac
Messages: 2797
Registered: April 2011
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You should be able to piggy back it off either of the existing taillights on the lead that's hot when brakes are on.
Sully
77 royale
Seattle
Sent from my iPhone
On Mar 4, 2013, at 6:36 PM, Larry Erd <1ljerd@gmail.com> wrote:
> I am hooking up my new 3rd break light, do I have to run a new wire from
> the light
> to the front to tie into the brake switch in front of the turn signal
> switch? Or is there
> a way to use diodes in the back? Could I use the extra blue wire if I have
> one?
> Larry Erd
> 77 ex Kingsley
> Getting ready for our maiden trip
> to Dothan
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] 3rd break light [message #200644 is a reply to message #200632] |
Mon, 04 March 2013 21:28 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
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| larry erd wrote on Mon, 04 March 2013 18:36 |
I am hooking up my new 3rd break light, do I have to run a new wire from the light to the front to tie into the brake switch in front of the turn signal switch? Or is there a way to use diodes in the back? Could I use the extra blue wire if I have one?
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Yes, you need to do "something" other than tapping into the brake light at the rear of the coach. (If you do that the 3rd brake light will blink with the blinker on what ever side you tapped into.)
You have two options:
1. You can run a wire from the output from the brake light switch before it feeds the turn signal switch back to your center brake light. This might not be as bad as it seems. I have been told there is already an unused (blue) wire in the harness from the left corner of the dash to the left tail light area. (It was for trailer brake uses.)
2. You can get a module designed for this purpose. Here is an example... I am not necessarily recommending it because i haven't used one: <http://www.commandelectronics.com/logicmodule.html>
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: [GMCnet] 3rd break light [message #200663 is a reply to message #200662] |
Tue, 05 March 2013 04:03 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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3rd brake light can be driven correctly by two SCRs and two resistors. Very simple circuit. requires feed from both the left and right brake lights. Cost is very little, less than $2 with internet shopping. Probably less the $10, if you have to use Radio Shack.
Ill scan the schematic and e-mail it to you later.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] 3rd break light [message #200671 is a reply to message #200663] |
Tue, 05 March 2013 07:03 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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Could you point me towards a schematic for that?
Thanks,
Johnny
'76 23' transmode norris
'76 palm beach
From: Thomas Phipps <tph1pp5@yahoo.com>
To: gmclist@temp.gmcnet.org
Sent: Tuesday, March 5, 2013 5:04 AM
Subject: Re: [GMCnet] 3rd break light
3rd brake light can be driven correctly by two SCRs and two resistors. Very simple circuit. requires feed from both the left and right brake lights. Cost is very little, less than $2 with internet shopping. Probably less the $10, if you have to use Radio Shack.
Ill scan the schematic and e-mail it to you later.
Tom, MS II
--
1975 GMC Avion, under forever re-construction
Vicksburg, MS. 3.7 miles from I-20
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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: [GMCnet] 3rd break light [message #200682 is a reply to message #200666] |
Tue, 05 March 2013 09:03 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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the module is easier to use
- all the connections needed, are inside the driver side, rear light
- the wires to the light can go up the crack in the rear outside panel
http://gmcmotorhome.info/body.html#CAMERA
- cover the wires with a 1/4 in vac hose in the crack
- all done with wire taps and crimps
- fast
- easy
- all commercial
- no wiring or circuits needed
- but - do it your way - is what makes life unique
gene
On Tue, Mar 5, 2013 at 3:38 AM, gene Fisher <mr.erfisher@gmail.com> wrote:
> did you read here?
> http://gmcmotorhome.info/brakes.html#third
>
> gene
>
>
>
> On Mon, Mar 4, 2013 at 6:36 PM, Larry Erd <1ljerd@gmail.com> wrote:
>
>> I am hooking up my new 3rd break light,
>>
>
>
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] 3rd break light [message #200712 is a reply to message #200704] |
Tue, 05 March 2013 14:00 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| A Hamilto wrote on Tue, 05 March 2013 11:24 |
| A Hamilto wrote on Tue, 05 March 2013 10:37 |
| emerystora wrote on Mon, 04 March 2013 21:12 |
Unfortunately, that will not work on the GMC motorhome because our brake lights are also our turn signal lights. If you hook the 3rd brake light to one of the brake lights then it will flash on and off with the turn signal. ...
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A flashing third brake light might not be a bad thing. Might get attention better than a steady light.
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I never took the EIT, much less the PE, but why couldn't you feed the positive connector of the 3rd brake light from each of the left and right brake light wires, with a diode in each leg that prevents current from the side that is not blinking from feeding to the side that is blinking?
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If you do that, every time you turn on a turn signal without stepping on the brake, the new 3rd brake light will flash.
I saw one where the owner split the 3rd brake light in half and wired each half directly attached to the turn signals. It was not quite kosher but it worked.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] 3rd break light [message #200723 is a reply to message #200632] |
Tue, 05 March 2013 18:59 |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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"Brake" light.
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: [GMCnet] 3rd break light [message #200790 is a reply to message #200697] |
Wed, 06 March 2013 14:31 |
cargeezer
Messages: 18
Registered: March 2013
Location: Coshocton OH
Karma: 0
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Junior Member |
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thanks Gene -
please refer to my edited post and maybe the idea will be more clear to you - I havent learned how to upload pics on this site yet-
Rick
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