Trailer lights making me insane !!!

[IGeeky1]

Vehicle is a jeep Cherokee. The lights have worked fine in the past when connected to a bike trailer and currently when connected to my boat trailer. My jet ski trailer however is making me insane. has a four wire harness. So did the bike trailer and my boat.

Jet-ski trailer lights were giving me problems so I replaced the entire wiring harness and both rear light assy with a new 4 wire. All connection were soldered, I don't trust twisty connectors with water. I did not connect the side markers yet.

Press brakes, maybe one, maybe the other, maybe none light. The more I play the more they do not work. I figure I have a galvanized trailer so it has to be a ground issue. so I run an additional wire for ground. It connects to white at front of trailer and to the white wires of the submersible lights. All connection to trailer frame remain as well. I figure I have to be golden now...

nope. same garbage

Meter at vehicle harness, all looks good. Remove all lights and meter brakes and turn signals at light boxes, all looks good, 12+.
Disconnect harnesses from each other and check with ohmmeter on trailer to be sure nothing is shorted (lamps remained out for this test) everything is open as it should be.

Put only one main lamp back in left side. Hit brakes, bright light! Add same to other housing..nothing in either now. Remove lamp from right side, still nothing on left. Remove and reinsert left lamp...light. Remove lamp from left and place in right....light. Add one to left. nothing, both off again. Remove both main lamps and reinstall, both light! cycled 6 times and everything looked good! added small side lights. now get nothing again. Remove side lights, nothing. Remove all and put back in mains, nothing. Put one main back on left, light...ho hum


It almost feels like it is not getting enough current but the other two trailers lit fine leading me to believe the vehicle is supplying plenty. And all of this low current theory is ruined by turning on the head lights.

When I turn on the headlights all the trailer lamps light up. turn signals still don't work nor does anything get brighter with brakes applied. But it does pretty much kill the bad ground or low current theories.

 

[colbyt]

Re: Trailer lights making me insane !!!

Buy one of these sold every where at various prices Four-Way Trailer Light Tester and determine which side of the ball the problem is on. It sounds like a classic case of a bad inverter but before we go there let's be sure.

 

[IGeeky1]

Re: Trailer lights making me insane !!!

OK, picking one up at summit racing along with another Curt T Harness to have on hand should that be the problem. If it isn't' it is easy to return. I've just been so sold on it being a trailer side problem not the vehicle side since the other trailer is working fine.

 

[Notrab]

Re: Trailer lights making me insane !!!

What happens when you put the hazards on as both brake and turn are same

 

[colbyt]

Re: Trailer lights making me insane !!!

and currently when connected to my boat trailer

I missed the and currently part. Look for a grounding issue.

 

[IGeeky1]

Re: Trailer lights making me insane !!!

What happens when you put the hazards on as both brake and turn are same

nada thing

 

[IGeeky1]

Re: Trailer lights making me insane !!!

I missed the and currently part. Look for a grounding issue.

I missed the and currently part. Look for a grounding issue.

Yeah, I guess I have zero idea what to look for, I've run a ground wire from front of trailer white to both light whites.
I've metered continuous both on trailer and from vehicle ground to frame.

All I can figure is that something wonky is going on in the Curt T harness converter, but then why does it behave fine for boat? Oh well I hope to test more tomorrow if it decides not to rain after work.

 

[dswi]

Re: Trailer lights making me insane !!!

Could possibly be the grounding to the vehicle...check it.
With a different trailer the ground might be being made through the ball and hitch (not the wire to the vehicle).
I have a 91 wrangler and had a ground problem one time...right near the emergency brake (might be similar with yours).
If you ever go off road look for rust and/or bad ground connection to the wiring harness of the trailer (on the vehicle side).

Just my 2 cents worth.

 

[dswi]

Re: Trailer lights making me insane !!!

Just realized you are in Ohio...Do they salt the roads in winter???

Could lead to corrosion on vehicle / connections.

 

[Ibl0wstuffup]

Re: Trailer lights making me insane !!!

I bet the ground from the car is corroded. I had the same thing happen. Ground isn't good enough for the load of all the lights but carries just enough contunity to light one bulb. Run a ground straight from the battery negative to the white wire on the trailer just to to test it.

 

[bruceb58]

Re: Trailer lights making me insane !!!

Run a jumper cable from a bare metal spot on the frame of the vehicle to bare metal on the trailer and see if that causes that lights to work. If it helps, its your vehicle to trailer ground.

 

[UncleWillie]

Re: Trailer lights making me insane !!!

... Remove both main lamps and reinstall, both light! cycled 6 times and everything looked good! added blinkers. now get nothing again. Remove blinkers, nothing, remove all and put back in mains, nothing. Put one main back on left, light...ho hum...

I do not under stand the "Added Blinkers" Part. The Blinkers/Turn Signals are the same filaments as the Brakes.

"When it absolutely makes No sense at all, and it appears to be Possessed and Magic is at play .... It is a Ground problem!"

This looks like an intermittent Ground Issue.
To eliminate all other ground paths; Take the trailer OFF of the Ball and Remove the Safety Chains.
Do all your testing with ONLY the 4 Pin connecting the trailer to the Jeep. Nothing else!

Can you narrow down "NorthEast, Ohio"? Are we neighbors?

 

[Notrab]

Re: Trailer lights making me insane !!!

just for s**ts and GIGels hook it to another verichal and see what happens

 

[bruceb58]

Re: Trailer lights making me insane !!!

When I turn on the headlights all the trailer lamps light up. turn signals still don't work nor does anything get brighter with brakes applied. But it does pretty much kill the bad ground or low current theories.

This statement alone indicates bad ground. The ground is a sneak path through the brake light filaments. Take out the dual filament bulbs and the side clearance lights will go out.

 

[IGeeky1]

Re: Trailer lights making me insane !!!

This statement alone indicates bad ground. The ground is a sneak path through the brake light filaments. Take out the dual filament bulbs and the side clearance lights will go out.

OK, I see how that would be.

Sorry about the "blinkers" that should have read "small side lights" I have edited to correct.

I am in Wadsworth (west of Akron) and boat at West Branch.

The vehicle ground (off the Curt T harness) goes to a non-rusty paint scraped off spot on the vehicle body. I suppose running a wire from there to battery ground could not be a bad idea for testing.

I can't imagine it still being a ground issue after having run a separate ground wire but... yeah I gotta go through it again

Thanks

 

[UncleWillie]

Re: Trailer lights making me insane !!!

..The vehicle ground (off the Curt T harness) goes to a non-rusty paint scraped off spot on the vehicle body. I suppose running a wire from there to battery ground could not be a bad idea for testing.I can't imagine it still being a ground issue after having run a separate ground wire but... yeah I gotta go through it again ...

With the 4 Pin connector as the ONLY connection between the Jeep and Trailer;
Turn on your Tail Lights and 4 Way Emergency Flashers.
Place a Meter between the Trailer Frame and the Jeep Frame.
Anything bigger than ~1 volt is an indication of a Grounding Problem.

 

[Silvertip]

Re: Trailer lights making me insane !!!

If you own a battery charger (any size or type) you own the best trailer light diagnostic tool available (followed immediately by a Volt/Ohm/Milliammeter). Up 'til now you have not proven whether the problem is at the tow vehicle end or the trailer end. So go park the tow vehicle somewhere and lets concentrate on the trailer. Connect the ground clip from the charger to the trailer frame (as in a nice clean, thoroughly tightened bolt). Now fetch a nail (virtually any size will work) and clip the POSITIVE clip onto it. You now have a voltage probe. Touch the nail to the connector terminal with the brown wire. All of the side markers, tail (running) and center marker lights should light. If some do and some don't, those lights have bad bulbs, bad fixtures, bad ground, and/or bad +12 volt connections. If none of those lights work, you have a +12 volt feed problem that can be anywhere from the connector, a break in the brown wire, or a missing ground connection. I suggest you remove the lenses from the lamps and take a good look at how the wires are attached INSIDE the lamp housing. Many of those a made where the bar wire end is simply "stuffed" into a cheap connection that grips the wire. Two corrections to make if that's the case. 1) remove the wire and "tin" the end with a soldering iron and ROSIN CORE solder. Now push the wire into the connection. 2) Solder the wire to the connection inside the lamp (without melting the lamp housing).

Most lamps take a #1034 or 1157 dual filament bulb. Lamp housings are made so poorly that the unknowing owner can put the bulb in 180 degrees wrong which creates all sorts of weird light reaction. Hold the bulb in front of you and look at the two locating nubs. Note that they are not in line with each other. That's because they are locating nubs and are there to help you prevent incorrect insertion.

If your trailer tongue is bolted or hinged (tilt trailers) you need to have a ground strap around those bolted joints. Remember -- ground is a continuous circuit. It cannot be interrupted by joints with poor electrical contact. One of the bolts that holds the lamps to the trailer is typically a ground stud as well. Again, look at the inside of the lamp to determine that.

Once you get the running lights going, touch the nail to the next terminal (yellow or green). Only the bright filament on that circuit should light. If it doesn't it is NOT a ground issue because you fixed in when you fixed the running lights.

If everything is working fine with the charger, but not when connected to the tow vehicle, fix the tow vehicle.

 

[IGeeky1]

Re: Trailer lights making me insane !!!

Thanks all, hope to get to try these new suggestions soon. Hope our local monsoon gives me a break.

 

[U.S.S. Too Tall]

Re: Trailer lights making me insane !!!

I was having a problem with my left side trailer lights. Both the stop/turn, and all running lights on the left side would not work, but after the trailer went into the water, everything worked fine. So, I knew it to be a ground issue. My answer was to remove all the lights an wires, and install a new LED kit. now everything works great. No issues at all!
All tho, it may have been easier, if the boat was off the trailer at the time I did the work.....

 

[IGeeky1]

Re: Trailer lights making me insane !!!

If you own a battery charger (any size or type) you own the best trailer light diagnostic tool available (followed immediately by a Volt/Ohm/Milliammeter). Up 'til now you have not proven whether the problem is at the tow vehicle end or the trailer end. So go park the tow vehicle somewhere and lets concentrate on the trailer. Connect the ground clip from the charger to the trailer frame (as in a nice clean, thoroughly tightened bolt). Now fetch a nail (virtually any size will work) and clip the POSITIVE clip onto it. You now have a voltage probe. Touch the nail to the connector terminal with the brown wire. All of the side markers, tail (running) and center marker lights should light. If some do and some don't, those lights have bad bulbs, bad fixtures, bad ground, and/or bad +12 volt connections. If none of those lights work, you have a +12 volt feed problem that can be anywhere from the connector, a break in the brown wire, or a missing ground connection. I suggest you remove the lenses from the lamps and take a good look at how the wires are attached INSIDE the lamp housing. Many of those a made where the bar wire end is simply "stuffed" into a cheap connection that grips the wire. Two corrections to make if that's the case. 1) remove the wire and "tin" the end with a soldering iron and ROSIN CORE solder. Now push the wire into the connection. 2) Solder the wire to the connection inside the lamp (without melting the lamp housing).

Most lamps take a #1034 or 1157 dual filament bulb. Lamp housings are made so poorly that the unknowing owner can put the bulb in 180 degrees wrong which creates all sorts of weird light reaction. Hold the bulb in front of you and look at the two locating nubs. Note that they are not in line with each other. That's because they are locating nubs and are there to help you prevent incorrect insertion.

If your trailer tongue is bolted or hinged (tilt trailers) you need to have a ground strap around those bolted joints. Remember -- ground is a continuous circuit. It cannot be interrupted by joints with poor electrical contact. One of the bolts that holds the lamps to the trailer is typically a ground stud as well. Again, look at the inside of the lamp to determine that.

Once you get the running lights going, touch the nail to the next terminal (yellow or green). Only the bright filament on that circuit should light. If it doesn't it is NOT a ground issue because you fixed in when you fixed the running lights.

If everything is working fine with the charger, but not when connected to the tow vehicle, fix the tow vehicle.

Sorry to delay so long I was busy killing my boat for a while instead

Connected charger negative to frame, went to each post one by one and all lights worked as they should!
Put trailer tester on vehicle went through running lights, left turn right turn, brakes and all worked just right.

...of course!

I can't imagine any results that could have been less helpful...lol