| [GMCnet] trailer harness wiring question [message #352427] |
Wed, 26 February 2020 15:30  |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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I was going to wire a unique stop light that mounts in hubcap attached to
the spare tire. As I understand the four wire trailer system the tail lights
(brown wire) should not be connected to either stop light. I my case each
stop light pin (green, yellow) have tail light power when the headlights are
on.
Suggestions assuming I am right.
Thanks!
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: [GMCnet] trailer harness wiring question [message #352439 is a reply to message #352429] |
Thu, 27 February 2020 00:35  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Len,
USA designed vehicles, which a GCM MH is, use a 2 element bulb to accomplish all of that. One element is solely for tail lights and the second brighter element is used for BOTH turn and brake lights. (Foreign designed vehicles use a separate bulb turn and brake.)
So for what you are doing (Adding a center mounted brake light) ignore brown completely (taillight). That leaves 3 wires. Ground (white) which you will need, and yellow and green which are combination turn and brake lights. What you will need is some way to determine whether the light is in turn signal mode or brake mode. They make a little module for that. It is usually found on lights that people buy and install in their trailer hitch receiver. It will get wired to both yellow and green and have a single wire out (color unknown to me) that goes to the brake light
Here is an example of one of the receiver mounted lights that has the module inside. If you can not find the module by itself, you could buy one of these and strip out the parts that you need.
https://www.ebay.com/itm/2-Red-15-LED-Trailer-Hitch-Receiver-Cover-Brake-Light-Inserts-w-Plug-Adapter/362800071185?hash=item547891c211:g:4O8AAOSwzwBdv UzN
etrailer.com might be another place to find what you need.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] trailer harness wiring question [message #352446 is a reply to message #352439] |
Thu, 27 February 2020 10:58 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
|
Senior Member |
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Ken,
I have that type light on my Jeep as well as the Nissan Frontier, They work
well. From what I can tell the gent that wired the tail light power (brown
wire) with each of the stop/turn signal wires so I have power for the stop
light running in the feed when I have the lights in independent of the brown
wire. With the lights on I have 12vdc in the brown wire as well as the
yellow and green wire. I seems I need to rewire that plug. The trailer
wire harness seems to go into the body. somewhere near where the driver's
side stop light lives.
I found a round glass stop light with the words STOP etched on the inside.
I rewired it for LED as it only had an 1156 bulb inside. I'll send pics
after the rally this weekend.
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, February 26, 2020 10:36 PM
To: gmclist@list.gmcnet.org
Cc: Ken Burton
Subject: Re: [GMCnet] trailer harness wiring question
Len,
USA designed vehicles, which a GCM MH is, use a 2 element bulb to accomplish
all of that. One element is solely for tail lights and the second
brighter element is used for BOTH turn and brake lights. (Foreign designed
vehicles use a separate bulb turn and brake.)
So for what you are doing (Adding a center mounted brake light) ignore brown
completely (taillight). That leaves 3 wires. Ground (white) which you
will need, and yellow and green which are combination turn and brake lights.
What you will need is some way to determine whether the light is in turn
signal mode or brake mode. They make a little module for that. It is
usually found on lights that people buy and install in their trailer hitch
receiver. It will get wired to both yellow and green and have a single wire
out (color unknown to me) that goes to the brake light
Here is an example of one of the receiver mounted lights that has the module
inside. If you can not find the module by itself, you could buy one of
these and strip out the parts that you need.
https://www.ebay.com/itm/2-Red-15-LED-Trailer-Hitch-Receiver-Cover-Brake-Lig
ht-Inserts-w-Plug-Adapter/362800071185?hash=item547891c211:g:4O8AAOSwzwBdvUz
N
etrailer.com might be another place to find what you need.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: [GMCnet] trailer harness wiring question [message #352455 is a reply to message #352427] |
Thu, 27 February 2020 14:48 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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You can buy a logic module which pretty much works. For a piece of wire, thouth, the better way is to simply hang a relay under the dash hooked to the brake switch and put 12V on thye wire to the rear light. Use an LED brake light and the current is minimal.
--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: [GMCnet] trailer harness wiring question [message #352463 is a reply to message #352427] |
Fri, 28 February 2020 00:30 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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There is something strange here. You have two identical failures on two different circuits. (yellow and green). If you are testing these leads under a no load condition then, then I can see two possibilities.
1. You have a floating ground on one or both of the lamps
2. You have a short in one of the sockets or bulbs between yellow and green. The odds of both sides (Driver and passenger) having the same failure are pretty high.
Is the wring that you are working with OEM? I am wondering if some PO rewired something and did not follow OEM color code.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] trailer harness wiring question [message #352527 is a reply to message #352463] |
Mon, 02 March 2020 09:30 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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I played with it at the rally over the weekend along with some help. There
seems to be a short in the trailer plug on the coach. The plug is connected
to the original factory harness minus the blue wire. I'll splice in a new
plug today or tomorrow.
: )
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken
Burton via Gmclist
Sent: Thursday, February 27, 2020 10:30 PM
To: gmclist@list.gmcnet.org
Cc: Ken Burton
Subject: Re: [GMCnet] trailer harness wiring question
There is something strange here. You have two identical failures on two
different circuits. (yellow and green). If you are testing these leads under
a no load condition then, then I can see two possibilities.
1. You have a floating ground on one or both of the lamps
2. You have a short in one of the sockets or bulbs between yellow and
green. The odds of both sides (Driver and passenger) having the same
failure
are pretty high.
Is the wring that you are working with OEM? I am wondering if some PO
rewired something and did not follow OEM color code.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: [GMCnet] trailer harness wiring question [message #352588 is a reply to message #352446] |
Thu, 05 March 2020 12:32 |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
|
Senior Member |
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|
Bad trailer plug on the coach. Cut it off, replaced with a new one and all
is well!
Thanks all!
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Len
Novak via Gmclist
Sent: Thursday, February 27, 2020 8:59 AM
To: gmclist@list.gmcnet.org
Cc: Len Novak
Subject: Re: [GMCnet] trailer harness wiring question
Ken,
I have that type light on my Jeep as well as the Nissan Frontier, They work
well. From what I can tell the gent that wired the tail light power (brown
wire) with each of the stop/turn signal wires so I have power for the stop
light running in the feed when I have the lights in independent of the brown
wire. With the lights on I have 12vdc in the brown wire as well as the
yellow and green wire. I seems I need to rewire that plug. The trailer
wire harness seems to go into the body. somewhere near where the driver's
side stop light lives.
I found a round glass stop light with the words STOP etched on the inside.
I rewired it for LED as it only had an 1156 bulb inside. I'll send pics
after the rally this weekend.
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, February 26, 2020 10:36 PM
To: gmclist@list.gmcnet.org
Cc: Ken Burton
Subject: Re: [GMCnet] trailer harness wiring question
Len,
USA designed vehicles, which a GCM MH is, use a 2 element bulb to accomplish
all of that. One element is solely for tail lights and the second
brighter element is used for BOTH turn and brake lights. (Foreign designed
vehicles use a separate bulb turn and brake.)
So for what you are doing (Adding a center mounted brake light) ignore brown
completely (taillight). That leaves 3 wires. Ground (white) which you
will need, and yellow and green which are combination turn and brake lights.
What you will need is some way to determine whether the light is in turn
signal mode or brake mode. They make a little module for that. It is
usually found on lights that people buy and install in their trailer hitch
receiver. It will get wired to both yellow and green and have a single wire
out (color unknown to me) that goes to the brake light
Here is an example of one of the receiver mounted lights that has the module
inside. If you can not find the module by itself, you could buy one of
these and strip out the parts that you need.
https://www.ebay.com/itm/2-Red-15-LED-Trailer-Hitch-Receiver-Cover-Brake-Lig
ht-Inserts-w-Plug-Adapter/362800071185?hash=item547891c211:g:4O8AAOSwzwBdvUz
N
etrailer.com might be another place to find what you need.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
--
This email has been checked for viruses by AVG.
https://www.avg.com
_______________________________________________
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Unsubscribe or Change List Options:
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_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: [GMCnet] trailer harness wiring question [message #352597 is a reply to message #352427] |
Fri, 06 March 2020 12:45 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
I got a heathen chinee wire loom from Wall and Mart, the colors were correct as posted here, but the wires were also stamped in english. Hard to screw up. The conductor is like nothing gauge, so incandescent bulbs run dim, but LEDs are plenty bright, the lower current means negligible voltage drop.
--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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