trailer light problems , need help!!!!!

reddog349

Petty Officer 1st Class
Joined
May 23, 2005
Messages
331
Im haveing a problem with my trailer lights. It seems the the turn signal is weak (blinks fast) and wont work with brakes applied.It works fairly good if I turn off the running lights.<br />I have replaced the wiring harness , new ground, new wires and lights but still the same problem.
 

bomar76

Lieutenant Commander
Joined
Jun 27, 2002
Messages
1,963
Re: trailer light problems , need help!!!!!

It's a bad ground.
 

reddog349

Petty Officer 1st Class
Joined
May 23, 2005
Messages
331
Re: trailer light problems , need help!!!!!

I drilled a new ground to the frame of the truck and one to the trailer. Is it possible the frame is a bad ground?Also would the flash "thingy" that is on the fuse block be bad and cause this?
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: trailer light problems , need help!!!!!

if the turn signal is on dimly when the brakes are applied it's a weak ground. It could be fooling your car into thinking a bulb is out. The light fixture gets grounded from being fastened to the trailer frame, so make sure it's on tight, on an unpainted surface, rust can inhibit the ground. Also the white wire on the trailer connector has to be fastened tightly to a bolt or something. The car ground gets its ground from the vehicle wiring harness, usually, not sure what you did with your drill. Try connecting the vehicle frame to the trailer frame with a jumper cable, see if it improves - could be a weak spot in your connector.
 

bomar76

Lieutenant Commander
Joined
Jun 27, 2002
Messages
1,963
Re: trailer light problems , need help!!!!!

Originally posted by reddog30:<br /> Also would the flash "thingy" that is on the fuse block be bad and cause this?
No.<br /><br />It's a ground problem.<br />You have a poor ground somewhere, either your connections to the frames or in the connectors, but it's 100% a poor ground issue.<br />How are the grounds at each tailight done?<br />I'd look there.
 

scotty c

Petty Officer 2nd Class
Joined
May 19, 2005
Messages
145
Re: trailer light problems , need help!!!!!

nice haircut bomar!
 

imported_Curmudgeon

Chief Petty Officer
Joined
Sep 29, 2004
Messages
496
Re: trailer light problems , need help!!!!!

Your ground is fine and you need to get a heavy duty flasher. The brake and turn signal are the same filament, and the brake will override the turn.
 

reddog349

Petty Officer 1st Class
Joined
May 23, 2005
Messages
331
Re: trailer light problems , need help!!!!!

OLD CURMUDGEON got it (mostly).<br />I replaced the filament with a heavy duty one and the turn signals work great. The 4 way flashers donot so ill gonna try a ground and will let you know.
 

reddog349

Petty Officer 1st Class
Joined
May 23, 2005
Messages
331
Re: trailer light problems , need help!!!!!

Well I took it to get inspected and they didnt seem to care about the 4-way being very weak as long as the turn signals worked.<br />It passed inspection although the did give me some greif over the marker light placement but let it pass because it appeared to be made that way.<br />Thanks for everyones help
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: trailer light problems , need help!!!!!

i've given up on using the trailer frame for the ground, i just run 3rd wire to each light, and attach to the mounting bolt. has cut down on a lot of problems.
 

ST

Petty Officer 2nd Class
Joined
Jul 25, 2005
Messages
192
Re: trailer light problems , need help!!!!!

I'll do the same the next time I have a ground problem!
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: trailer light problems , need help!!!!!

a lot of the newer vehicles use non metalic houseings for the lights now. thus the sockets themselves, have a ground wire. i run the white ground wire to one of the socket grounds, and it has elimanated the grounding problems.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,815
Re: trailer light problems , need help!!!!!

I think the best way is to do as Tasha says, run a seperate ground wire to each light fixture. Back in the 70s I had a fiberglass dune buggy on a VW frame, and I always had light problems with it, until I realized that my grounds were not good and once I fixed that up no more problems. With the 'glass body you had 2x the normal # of wires since each light had to have a seperate ground, and sometimes just running it to the frame doesn't work because of corrosion, so I ran seperate wires back to where the battery grounded to the frame.<br />Now if you don't want to do that much work, snaking wires and such, you could do it this way: make sure the white wire from the trailer harness is attached firmly to the tougue. Then run 2 white wires from the tongue to the frame side rails. Next, run a white wire from the end of each side rail to the rear crossmember where the stop, turn, brake and clearance lights are. That way if there is corrosion in the bolts holding the sections of the trailer frame together, it will not interrupt the ground path.
 
Top