GM Trailer Wiring Help Please

Joined
Apr 15, 2002
Messages
29
My trailer harness has comming out of it<br />Brown, Brown/Green and Brown/Yellow wires....How do I wire this to a 4 wire Flat plug on a GM truck. GM plug has White, Brown, Yellow and Green wires...The trailer has left and right red lights and left and right amber lights.....thx for your help... :)
 

Parrott_head

Chief Petty Officer
Joined
Feb 15, 2002
Messages
634
Re: GM Trailer Wiring Help Please

Ok, near as I can remeber.<br />1) From your truck: White=Ground, Brown=Taillamps, on when headlights are on, Green= One of the turn signal/brake light, Yellow= The other turn signal/Brake light.<br /><br />Now on your trailer found out which side the yellow wire goes and which side the green wire goes. This will tell you which is left and right. <br /><br />You could buy a cheap test light at an auto supply to check what is coming out of your truck. I would strongly suggest this since you never know who wired up your vehicle.<br />The white wire on the trailer plug should be grounded to the trailer frame. Do not reley on the trailer ball and chains for the lamp ground.
 
Joined
Apr 15, 2002
Messages
29
Re: GM Trailer Wiring Help Please

Since the brown/green and brown/yellow are together coming out of trailer harness what would I hook the single brown wire to coming out of the trailer harness.....Thx.... :)
 

ebbtide176

Commander
Joined
Jan 22, 2002
Messages
2,289
Re: GM Trailer Wiring Help Please

did you get this wiring problem solved? since you hafta drive 75mi to do it, i guess u need to be well prepared when u get there...
 

ebbtide176

Commander
Joined
Jan 22, 2002
Messages
2,289
Re: GM Trailer Wiring Help Please

ok, well i will be offline soon(home modem dead)but i'll give a briefing on what might do the trick. <br />your trailer has amber + red fixtures, so hopefully the redz have brake + taillights. you can tell this by lookin for 2 filaments to be in the bulbs. if you're lucky, the amber lights have no wires, and the red ones have <br />driver side=yellow/brn + brn<br />passg side =green/brn + brn<br />and the solid brns might be tied into 1 brn b4 getting to front of boat. so to hook to the truck plug, just hook yellow to yellow/brn, green to green/brn, brn to brn, white to frame on trailer (grounding wire)<br /><br />BUT this trailer(did you find out where the wires come out of the fixtures and what colors?) probably has <br />driver amber= yellow/brn<br />passg amber = green/brn<br />ea red fixt = brn(going into 1 wire at front)<br />and you'd hafta use ambers for brake lights too!!<br />not a good idea. <br /><br />time for new red fixtures that have 2 filaments, are dim red with parking lights(brn) and both come on bright(2nd filament-green & yellow) for brakes, and one blinks, the other bright if t/signal & brakes (same green or yellow does this automatically).<br /><br />remember you can get a little stripped piece of wire to jumper from your truck plug (turn parking lights on, and jumper from brown on plug) to "touch" the other wires momentarily to see just what the heck lights up. you will get a little tiny spark when on a bulb wire, but a grounded wire will pop(and you might need another parking light fuse in the truck)<br />HTH
 

ebbtide176

Commander
Joined
Jan 22, 2002
Messages
2,289
Re: GM Trailer Wiring Help Please

i just thought about something else... hope you print this stuff out to refer to, since there are many variables here.<br />when you say brn, brn/yellow,brn/green - are you talking about 3 wires or 5 ?!! (i'd forgotten about the NZ info on other posts)<br />IF you're talking about 5 wires,with the brn/yellow&brn/green being 2wirestrips, then probably the ambers are 2filaments, with 1=taillights,1=t/signal,and then the reds have 1 wire used for brakes(bright lights i hope). This might be used in some places, dunno if amber taillights are legal. And you'd need the converter box (from other posts). But you didn't really give related info, like: Do you HAVE to get this boat home with it 'as is', or 'you can't install new fixtures/converter' where it is? For an emergency/temporary situation, i guess you might connect:<br />truck trailer<br />-------------------------<br />white white(or screw on frame/gnd)<br />yellow yellow<br />green green<br />brn both brns with green/yellow<br />(this would give dim amber=taillights, bright amber=brake & t/signal lights)<br />or<br />white same/ground<br />yellow yellow<br />green green<br />brn single brown wire<br />(this would give red taillights-maybe bright tho,amber brake & t/signal lights)<br />whew! the only other option i guess not covered.............<br />driver red=brn/yellow(2wire strip)<br />passg red=brn/green (same)<br />both ambers = brns into 1 at front<br />(still need a converterbox)emergency=<br />truck trailer<br />----------------------<br />white gnd/white/trailerframe<br />yellow yellow<br />green green<br />brn single brn<br />(this gives red brakes & t/signal, amber taillights)<br />did i leave out sumthin? good luck
 

DP

Petty Officer 1st Class
Joined
Sep 18, 2001
Messages
209
Re: GM Trailer Wiring Help Please

Don't know what year your truck is, but with some of the newer ones you can waste the system if it is hooked up wrong. Go to a GM dealer or buy an aftermarket T connector that goes into the wiring harness and ends in the flat 4 trailer connector.<br />Probably run you $25.00 or so and well worth it.
 
Joined
Apr 15, 2002
Messages
29
Re: GM Trailer Wiring Help Please

Thanks again Ebttide....I appreciate you taking the time for all the info....I'm sure one of your suggestions will work........ :D
 
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