Trailer wiring headache

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lopez11j

New member
Trailer worked last year but wires corroded off.

Factory 7 way on truck. I used meter and everything is fine on the truck side.

Hooked up wires how they should be on the trailer plug and I can get the blinkers to work but not the running lights or break lights.

Current hook up:
Green - trail & running lights
Red - Left blinker and brake (light blinks, no brakes)
Orange - Right blinker and brake (light blinks, no brakes)
White - common

any suggestions?
 
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lopez11j

New member
Where do I check it? Is the white wire bolted to the frame somewhere? Wires run through the tongue and side rails and are not visible.
 
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pez

Member
Follow the wires under the trailer. On an older trailer of mine there were splices or connectors that corroded under the tounge of mine. It usually isn't a straight shot from front to back. I have a junction box inside the v on my new legend.
 
indy_500

indy_500

Well-known member
Just went through this on our older enclosed. All of our wiring is getting corroded, tried replacing as much as possible and it works now. The trailer wiring on my truck didn't work when i got it, some idiot just stuck the ground wire in between the hitch and the frame and it was all rusty, had to grind off a fresh spot and put a bolt through it.
 
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ezra

Well-known member
I had been running a roach clip on a 3 ft wire stuffed in to my ground plug then plugged in to flat4 to round adapter and roach clip clipped to bumper.2 yrs lol finally a bud wanted to borrow my clam to go to tog said sure you rewire it now it is all good did not cost me a lick of time.
may be there tonight on the cam white Triton with AC racing with diamond plate flames and all new wiring
 
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snake

Member
yep,make sure you got a good ground! also,if you got wiring that goes thru the frame,this is where mice love to get in and chew wires. I just bought a new trailer and first thing i did was plug these openings
 
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lopez11j

New member
Replaced the corroded plug and I now have blinker, brake lights and tail lights. The problem is when the tail lights are on and I turn on the blinker, all the lights on the trailer blink. I searched all over for a ground connected to the trailer frame and found none. The trailer lights did work last season so I am perplexed. I will splice into the ground wire and connect it to the frame to see if that solves my problem. I'll let you know.
 
legend02

legend02

Active member
I added an extra ground wire off the plug a few years back when I had the same issue with all the lights blinking, not sure where the original ground wire broke.Trailer is a R & R tilt with a Cap.
 
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snake

Member
yep,typical bad ground symptom!! on tilts i have mounted a heavy gauge wire from tongue to trailer frame,do it rite where it tilts. use like an 8" wire with eyelet on each end and self tap screws,just mount so it doesnt get tight when tilted
 
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lopez11j

New member
Grounded tongue and tilt part of trailer. Redid all wire connections. Still have the same problem. Everything works individually but not together. Frustrating.
 
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jimfsr

New member
Basic trailer wireing...Green-right brake and blinker
yellow-left brake and blinker
black-reverse light
blue-elec. brakes
white-ground
brown-running lights
red-12v. power for acc.
green, yellow, white, brown for 4 pin.

Make sure all the wire colors are going to the correct power source in the 7 pin on the truck.
 
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muss

New member
I know this will seem to simple and may not be your problem, but I had the same problem with the turn signals and brake lights working but no running lights, I simply sprayed electrical cleaner in the male and female of the plugs, let it dry, and simply plugged it back in and wala I had running lights!
 
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snake

Member
a test light may not show a marginal ground,use a volt meter! again,you may have wires that have been chewed by mice,and now the bare strands are contacting the other wires! use an ohmeter at trailer harness and see if you have continuity between the 2 that are suspect. if you do,leave the meter on and start disconnecting lights,if it goes away=you found the source,if not,then check wireing. white=ground,brown=running lights,yellow=left,green=right
 
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lopez11j

New member
snake said:
a test light may not show a marginal ground,use a volt meter! again,you may have wires that have been chewed by mice,and now the bare strands are contacting the other wires! use an ohmeter at trailer harness and see if you have continuity between the 2 that are suspect. if you do,leave the meter on and start disconnecting lights,if it goes away=you found the source,if not,then check wireing. white=ground,brown=running lights,yellow=left,green=right
Click to expand...

Did that and more most of the day. Had my buddy come over and hook his truck up and the trailer works fine. So here's a tip for everyone. Don't spend 8 hours working on trailer lights without making sure its not a truck wiring problem.

05 trailblazer with factory 7 pin. Pins look clean. I'll tear into that tomorrow.
 
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snake

Member
hmmm,I guess your 1st post, saying you checked the truck with a meter,may have thrown us for a loop!! j.k.!! glad you got it fixed!! now go fix that snowmaking machine!
 
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