trailer harness wiring question

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b52rule

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Sep 16, 2008
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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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/
 
I'd say you have lost the ground for the rear lights and you need to fix that first, then use a logic circuit to power the third brake light you are
installing.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Brown is all tail & clearance

Yellow is left turn & stop

Green is right turn & stop

White is common/ground

D C "Mac" Macdonald
76 ex Palm Beach
"The MoneyPit"
OKC, OK

Sent from my iPhone

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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

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Unsubscribe or Change List Options:
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Ground is good.

: (

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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Terry
via Gmclist
Sent: Wednesday, February 26, 2020 2:00 PM
To: gmclist
Cc: Terry
Subject: Re: [GMCnet] trailer harness wiring question

I'd say you have lost the ground for the rear lights and you need to fix
that first, then use a logic circuit to power the third brake light you are
installing.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

_______________________________________________
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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
 
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:4O8AAOSwzwBdvUzN


etrailer.com might be another place to find what you need.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, February 26, 2020 10:36 PM
To: gmclist
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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Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
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https://www.avg.com
 
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
 
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
 
Brown is all tail lights
Yellow is left turn and stop
Green is right turn and stpp
White is common/ground

D C "Mac" Macdonald in OKC, OK
76 ex Palm Beach
"The Money Pit"

Sent from my iPhone

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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
Burton via Gmclist
Sent: Thursday, February 27, 2020 10:30 PM
To: gmclist
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

_______________________________________________
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
 
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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Len
Novak via Gmclist
Sent: Thursday, February 27, 2020 8:59 AM
To: gmclist
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
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
Burton via Gmclist
Sent: Wednesday, February 26, 2020 10:36 PM
To: gmclist
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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I got a 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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