| toad tow light question [message #121891] |
Fri, 15 April 2011 09:35  |
pbrownsd
Messages: 56
Registered: December 2010
Location: Hayden,ID
Karma: 0
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ok, I bought some trailer lights to mount on the back of my jeep. The four pin wiring harness from the motorhome appears to be done incorrectly, so I tapped the tail light wires themselves because we are leaving today. So now I have working blinkers and taillights. Stop lights come on, but only if the headlights are off. With headlights on, the taillights go off when the brake pedal is pressed. I'm talking about the trailer lights here, lights on motorhome work as they should. Any ideas?
1976 Glenbrook
Hayden, ID
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| Re: [GMCnet] toad tow light question [message #121893 is a reply to message #121891] |
Fri, 15 April 2011 09:43  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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I wonder if you have a bad ground. Sometimes the lights will go
through a light filament to find a ground.
If you have a test light go from the ground to each of the other three
wires.
1 with the headlights on the tail lights terminal should light the
test light.
2 with the right turn on the test light should flash
3. With the left turn on the test light should flash.
Since the brakes are just both turn signal lights coming on they
should work if you have a good ground.
Emery Stora
On Apr 15, 2011, at 8:35 AM, Pete <pbrownsd@yahoo.com> wrote:
>
>
> ok, I bought some trailer lights to mount on the back of my jeep.
> The four pin wiring harness from the motorhome appears to be done
> incorrectly, so I tapped the tail light wires themselves because we
> are leaving today. So now I have working blinkers and taillights.
> Stop lights come on, but only if the headlights are off. With
> headlights on, the taillights go off when the brake pedal is
> pressed. I'm talking about the trailer lights here, lights on
> motorhome work as they should. Any ideas?
> --
> 1976 Glenbrook
>
> Hayden, ID
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] toad tow light question [message #121896 is a reply to message #121893] |
Fri, 15 April 2011 10:44 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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| emerystora wrote on Fri, 15 April 2011 07:43 |
On Apr 15, 2011, at 8:35 AM, Pete <pbrownsd@yahoo.com> wrote:
> ... So now I have working blinkers and taillights.
> Stop lights come on, but only if the headlights are off.
> With headlights on, the taillights go off when the brake
> pedal is pressed. I'm talking about the trailer lights
> here, lights on motorhome work as they should. Any ideas?
I wonder if you have a bad ground. Sometimes the lights will go
through a light filament to find a ground. ...
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I do not just wonder, I am pretty sure Pete has a bad (or no) ground. The towd tail lights are acting just like the front side marker lights. (They are not attached to ground at all!)
Twin filament bulbs give some interesting results sometimes. The side can get a ground from the other circuit... through the filaments in the other bulbs. In this case the coach brake tail and marker filaments. Note that it is the low wattage filament that is "glowing" when regardless of the source of the voltage.
When voltage is applied to both circuits, all current flow stops. (You have seen cars with one bad tail light ground when they put on the brakes the light goes out?)
Considering both sides are effected AND the towd was just wired, I would check the common ground to the coach.
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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