Trailer Light Questions

[vermilionfox]

I'm having a problem with trailer lights. I have a full size Ford van with a 4 flat connector. On my old boat trailer I had intermittent problems with the tail lights. Picked up my new trailer for my new pontoon yesterday. The dealer hooked it up to a battery with a connector and all lights worked. Hook it up to the van, brakes and signals work but no tail lights! Tester plugged into the connector on the van shows good for the tail lights.

Help!!!!!

Any ideas?

[cybermuskie]

I had that problem the otherday with my 4-wheeler trailer, and it turned out to be the ground. I had to put a jumper wire between the trailer tounge, and the main box frame of the trailer. May not be the case for you, but may help.

[Guest]

Check the ground 1st before you do anything else.. most of the time that is the problem.

Even if it looks good, you might want to disconnect it at the vehicle and clean the contact point up. Put some dielectric grease on it when you hook it back up and that will help prevent corosion.

If the ground doesnt solve your problem.. trace back on the brown wire and make sure there is no damage, and the connection is good wherever its spliced in.

[Valv]

I agree....99% of trailer lights problems is ground related. Be sure you have good ground to it.

Sometimes is just enough to drive it few yards and it will make good contact.

[End of the Line]

Its almost always the ground. When you use the signal lights the ground finds its way back throught the unused circuit such as the tail lights or te other signal light. But when the tail lights are on the other light is already powered, no subsitute ground. Lots of times the ground it through the hitch instead of using the white wire. Thats never a good ground for long.

[Rost]

Exact Same problem I had 1 week ago. It is a fuse under the hood in your van. Directly in front of the drivers seat is a black fuse box. Open it and start pulling fuses until you find the culpret!!!!

Ford has a separate fuse for blinkers, brakes, and running lights. It will more than likely be a 15 amp fuse. My fuse was located in Position 7 and it was a 15 amp. The new fuse costed me 55 cents at Napa.

good luck!

[efgh]

I had the same problem as Rost, it was a fuse in the black box in the place he described, the trailer lites are fused seperately from the truck lites.

[ewirz]

I have a question- I lost my running lights. Tracked it down to a bad connection in the plug. I replaced the plug and fixed the running light problem. Now, my left turn signal comes one, but does not blink. All on the other lights work fine (running, right turn, breaks, flashers). Any thoughts?

ERW

[Ray Esboldt]

I am sure someone will answer this correctly, but isn't there a flasher relay in the fuse box that can fail? There is in my truck ('99 F-150), but it has never failed on me.

[Surface Tension]

Ray, there is a flasher relay. If that goes then your turn signals won't work. Some cars and trucks come equipped with flasher relays that aren't made for tailer lights. That symptom would be signals that flash fast with dull or not at all. That problem is solved easily by replacing that relay with a heavy duty type.

[ewirz]

I drive an 03 ranger. I guess its possible that the relay has gone bad. A week ago, before the problem surfaced, everything worked fine. No problems with signals without the trailer attached. I'll check the relay, but is it possible its something else?

[Jeremy airjer W]

Vermilion, So you have power on the brown wire at the wire wire connector on the vehicle. The next step is to see if that power is going to the trailer side of the connector. Plug everything in and backprobe the brown wire on the trailer side. Is there power now. If no, check the truck side of the connector again with everything plugged in, If there is no power on either side than we have a poor/corroded power wire, or pins in a connector, somewhere. If there is power on the on the truck side with everything connected and no power on the trailer side than I would suspect the 4 - way connector. The ground seems unlikely since the other functions work.

[Jeremy airjer W]

ewirz, if the Green arrow lights up but doesn't flash I would start by checking to see if any of the bulbs are illuminating on that side. If the green arrow doesn't light up I would probably start to suspect the turn signal switch but not before I checked to make sure that ford didn't have the two sides on different fuses. So I guess what we need to no is if the green arrow lights up and do any of the bulbs light up on that side?

[castindad]

valv where might i pick up electrial pigtails for older trailer lights castindad?

[BarryG]

Sounds like a burnt out bulb.

[MIKE IN lINO III]

I was also having a problem with my trailer running lights not working, after reading this thread I went home and checked my fuse. Sure enouph it was burnt out. What would cause this?

Mike

[FRESHWATER PETIE]

Ya, check all your trailer bulbs, and take each one out and look at them, both fillements should be good. Check for good contacts also.

[vermilionfox]

Just wanted to let everyone know that I needed a new connector on my vehicle. Put the new one on and she works like a champ now. The van still had the original Ford connector and it was 8 years old.

Thanks for all the advice.

[TommyJ33]

Good info guys.

Say, while we are on the subject of trailer lights.

left lights...I lose running lights when I depress the brake. no brake lights either. and just on the left side.

Everything else works. the weird thing checking with my circut tester...I do have power all the way to the light socket. it is just that the light bulb won't light up. and the bulb is good.

touble shooters...what do you think?

[marine_man]

I'd say you have a bad ground somewhere... either the connection between your vehicle and the trailer, or the light to the trailer frame. Verify that the white wire on the light pigtail on the trailer is attached to the frame somewhere and that you have the corresponding connection on your vehicle. If that's all good then check out how the light is grounded to the frame. You'll probably find your problem there.

marine_man

[Jeremy airjer W]

Ill vote for bad ground also.

[TommyJ33]

thanks Marine_man!

[Macgyver55]

Be sure to check the bulb socket itself. If its corroded and the brass base of the bulb is not making a good contact you wont have a ground either. Clean it out and put some anticorrosion grease on the bulb before you put it in.

[marine_man]

If only my words fixed your problem, right?

Glad to help...

marine_man