Trailer lights

[scrobo]

Hey all

I have a boat trailer and I hoked it up to my vehicle to move the boat around...


All my lights work but the right turn signal does not signal. The light lights up with the headlights but no flashy-flashy.

Is that a bulb problem or a wiring problem? Or even worse... a truck problem?

 

[bjcsc]

Re: Trailer lights

Most likely the second filament on the trailer's bulb is burned out. If the signals work on the truck when the trailer is not attached, you can rule the truck out. Pull the bulb and check it with a meter...

 

[BrianS.]

Re: Trailer lights

A few things that can be wrong. The running lights are on a different wire than the brake/turn signal.

So you can either have a bad wire going to the bulb (can be anywhere from the plug to the light itself) or the bulb can be burt out.

 

[burroak]

Re: Trailer lights

Hey all

I have a boat trailer and I hoked it up to my vehicle to move the boat around...


All my lights work but the right turn signal does not signal. The light lights up with the headlights but no flashy-flashy.

Is that a bulb problem or a wiring problem? Or even worse... a truck problem?

An obvious question, but since it was not stated in the original post, do all the lights function properly on the tow vehicle? If so, check out the filaments in the offending bulb. If ok, check the right turn circuit at the bulb base. Keep checking back toward the tow vehicle until the problem is found.

Many times the contacts on the bulb and socket are corroded. Sandpaper the socket contacts and scuff the bulb contacts. All the bulbs/sockets and the connectors should be put back together with a dielectric grease. It is basically an oxygen barrier and will prevent the corrosion in the future.

 

[rndn]

Re: Trailer lights

Make sure the trailer ground is cleaned at the bulb location as well as the main one near the hitch. Many trailer light issues are a bad ground.

 

[jtexas]

Re: Trailer lights

check your vehicle owners manual fuse chart.

I was surprised to learn that my ford splorer has separate fuse circuits for left trailer turn/brake and right trailer turn/brake.

 

[scrobo]

Re: Trailer lights

Gonna try to get to it today. Leaving Saturday morning and going to be on the road all week so I gotta fit alot fo things in. I have a chunk out of my sidewall in the front tire So I need to change my tires and find this light problem and so on and so on...

Still need to remount the boat seats too.

Wow.

Should have been on this a while ago

 

[reelfishin]

Re: Trailer lights

First, as said above, make sure the tow vehicle's lights are ok without the trailer plugged in. Second, with the trailer hooked up, do both trailer break lights work? If they do, chances are the bulbs are fine as most single light trailers use the same bulb filaments for both stop and turn functions.

Check your ground connections, both at the truck where the trailer light harness leaves the main harness and where the trailer's harness grounds to the trailer frame, if it's a tilt trailer, make sure the ground wire extends to the main frame. Make sure the light that's not working is also grounded to the trailer frame.

Most later model vehicles these days have separate trailer light circuits from the factory with their own fuses, and vehicles with amber rear turn signals often use a transistorized relay or converter to connect to a standard trailer. I have seen those converters go bad.

 

[scrobo]

Re: Trailer lights

First, as said above, make sure the tow vehicle's lights are ok without the trailer plugged in. Second, with the trailer hooked up, do both trailer break lights work? If they do, chances are the bulbs are fine as most single light trailers use the same bulb filaments for both stop and turn functions.

Check your ground connections, both at the truck where the trailer light harness leaves the main harness and where the trailer's harness grounds to the trailer frame, if it's a tilt trailer, make sure the ground wire extends to the main frame. Make sure the light that's not working is also grounded to the trailer frame.

Most later model vehicles these days have separate trailer light circuits from the factory with their own fuses, and vehicles with amber rear turn signals often use a transistorized relay or converter to connect to a standard trailer. I have seen those converters go bad.

Well...

No fuse for trailer turn signals.
Grounds are connected.
Only one filament in the bulb
Bulbs test ok
Does this on BOTH vehicles (Truck and car)

Still working on it.

 

[bjcsc]

Re: Trailer lights

Well...

No fuse for trailer turn signals.
Grounds are connected.
Only one filament in the bulb
Bulbs test ok
Does this on BOTH vehicles (Truck and car)

Still working on it.

Hmmm...one filament? Could be the wrong bulb. Most trailers use an 1157 and maybe you've got an 1156 in there. If there's only one bulb in the taillight housing, you've got the wrong bulb. When you pull the bulb out, are there two brass strips under it or one?

"Grounds are connected" doesn't mean anything. They have to be conducting...

"Does this on BOTH vehicles" doesn't mean anything either. You need to know what the vehicle does without the trailer attached to its lighting and with it attached...

 

[Bob_VT]

Re: Trailer lights

1. Has it ever worked before?

2. Who installed the vehicle harness on the tow vehicle?

3. What kind of tow vehicle is it? Toyota's use a converter for trailer lights.

4. Have you tested all the wires on the tailer and the ground points. Many trailers need individual grounds for each tail light and marger light.

 

[jtexas]

Re: Trailer lights

Most any vehicle made in the 90's american or foreign needs a converter, if it doesn't have factory trailer wiring.

Does the trailer have separate fixtures for taillights and brake/turn? Separate lamps inside the fixtures?

Get a 12V test light and make sure you're getting power from the vehicle connector, otherwise you don't know whether you're wasting your time. Same result on two vehicles *suggests* its a trailer problem but doesn't rule out a problem on both vehicles.

Then make sure the signal is getting through the trailer connector by piercing the insulation just beyond the connector with the test light probe.

 

[BrianS.]

Re: Trailer lights

Could be your connector also, where it plugs into your tow vehicle. I had a bad wire there.