tail light wiring

[Djanzen]

Hello all
two weeks ago I purchased a 2004 fleetwood prowler regal 2952b. this trailer is in incredible shape! It looks like new inside and out. but my problem is this, when the taillights are on and the brakes lights or signal lights are active, the taillights flash. first of all i will tell you guys that I am a Heavy duty Cat tech. I know about wiring! I have checked the wiring from front to rear with I magnifying glass, I have checked it with different vehicles, I have replaced the fifth wheel connector wiring with a heavy gauge seven wire cable, Every joint has been taken apart, cleaned, soldered and heat shrinked, I have installed temporary bypass wiring, I have installed a ground at each taillight,each ground wire is attached to the frame after i ground it to bare steel! I have eliminated 80 - 90 percent of the flashing, you can no longer see it in the daylight, but you can see it at night, with a multi meter is fluctuates between .3 and .6 of a volt. I am at my whits end here, no hair left on my head!!! Does anyone have any suggestions for things i have missed? my wife is telling me to let it go! YA i can't do that!! I need it to work correctly, this is a simple four wire system!!! green, brown, red, white, THAT IS ALL!

[King Richard]

Just a couple of dumb suggestions, try a different vehicle as the source, maybe it's the supply to the trailer?
Does it have the correct light bulbs? Are the bulbs solid in the sockets with good contacts? they bounce around a lot and can wear flat or get loose. also look at pin contacts on the connectors.
Hope you find it.

[Skip426]

When it comes to wiring issues I'd rather be lucky than good! 34 years automotive, taught me that.
Have you tried an external ground to the bulb it's self; touch a bare grounded wire to the exposed brass section of the bulb. Checked for an internal crossed filiment in the bulbs. Is the trailer end of the harness grounded to the hitch pin box, or right to the trailer frame ? You said you tried by-pass wiring. Did you by-pass the frame i.e. wire direct from light ground to hitch ground. When you say tail lights flash are the marker lights flashing also ?

Good luck, keep us informed if you find your solution.

[Djanzen]

Originally Posted by King Richard

Just a couple of dumb suggestions, try a different vehicle as the source, maybe it's the supply to the trailer?
Does it have the correct light bulbs? Are the bulbs solid in the sockets with good contacts? they bounce around a lot and can wear flat or get loose. also look at pin contacts on the connectors.
Hope you find it.

Yes done this

[Djanzen]

Originally Posted by Skip426

When it comes to wiring issues I'd rather be lucky than good! 34 years automotive, taught me that.
Have you tried an external ground to the bulb it's self; touch a bare grounded wire to the exposed brass section of the bulb. Checked for an internal crossed filiment in the bulbs. Is the trailer end of the harness grounded to the hitch pin box, or right to the trailer frame ? You said you tried by-pass wiring. Did you by-pass the frame i.e. wire direct from light ground to hitch ground. When you say tail lights flash are the marker lights flashing also ?

Good luck, keep us informed if you find your solution.

I have done external grounding, blubs have been replaced with new ones, and I should clarify it is the taillights have three 1157 bulbs two are wiring for taillights and signal/brake one is just tail, It is taillights and markers that flash

[Franka548]

Djanzen,
With the markers flashing with the signal/brake feed, that is the definite sign of a ground problem. Did you check the ground on the TV? Try a different TV. I have had similar problems due to corrosion and/or broken wires on the TV plug. I feel your frustration.

Frank

[Dunner]

It does sound like a ground problem. They can and will do weird things. I think you may have already checked it, but put a driver to all the tail and turn signal external light housings/fixtures, paying attention to what the lights do with each one. Don't just tighten, loosen and tighten.

[Engineer Guy]

Having done Troubleshooting on all sorts of Electronics and Vehicles, I years ago adopted strategies I called 'Troubleshooting 101'. It's the extremely rigorous application of small step Tests that assume nothing, and overlook nothing. Sometimes, a Notepad is handy to keep track of steps taken, especially in the likely case of being interrupted.

1. With the TV unplugged, I would use an Ohmmeter to check all connections. I would also look for any sort of resistance or crossfeed between 2 Filaments that ought not to be interconnected. If the TV Flasher sees 2 Filaments connected improperly in parallel [together], some Flashers will act 'strange', due to this unexpectedly-high resistance of 2 Filaments vs. the expected 1 Filament.

2. I would then look for resistances to Ground from the Ground connection at each Bulb location. I had a weird one on my 15' TT. The Running Light worked fine, but a Turn Signal at the rear did not. As first, I assumed 'Ground is Ground', right? Well, a false assumption. The lil Brass Rivet inside the Taillight Assembly connected dissimilar metals together. When I buffed it up with 'Scotchbrite', the problem disappeared. It made no sense 'logically', but rigorous Troubleshooting - assuming nothing - saved the day. If it is a bad Taillight Ground, as my pal also had on his 15' '88 Fleetwood, this method will find it.

3. Take the variable of the TV out of the equation. Use a spare Battery or Charger/Power Supply and some clips to safely make connections to the Trailer Lamps via the Harness.

4. The usual Factory technique is to connect the first Running Light. The +12 Lead goes in-and-out of that Light to the next one. And so on... Those connections are notorious for becoming intermittent. With Long Nose Pliers, carefully pull loose those connections inside the Running Light and reseat them. Look for little loose wire strands shorting out, and/or clip them off in a 'blind faith' move. I use a little Scotchbrite to scour inside the Bulb Socket, and to burnish the little Tabs on the side and the bottom of the Bulbs. Ya never know...

5. To isolate the problem, you sometimes have to resort to disconnecting Lamps one-at-a-time. This will steer you to where the problem Ground is, etc..

6. After you believe you've found the problem, connect the TV back up and see if it's truly fixed. A Power Supply puts out more current - and overcomes high resistance problems - more so than a TV Flasher run through potentially-undersized Wiring. But, in this step, you'll learn if it's an 'interactive' problem between the TT and TV.

I read the OP several times. Just skip any suggested steps here that repeat what you've already done. The hard reality is that something is still intermittent/interconnected.

My hunch, too, is that it's a Grounding issue. However, I set my own hunches aside to apply Troubleshooting rigor mercilessly.

[Djanzen]

Originally Posted by Engineer Guy

2. I would then look for resistances to Ground from the Ground connection at each Bulb location. I had a weird one on my 15' TT. The Running Light worked fine, but a Turn Signal at the rear did not. As first, I assumed 'Ground is Ground', right? Well, a false assumption. The lil Brass Rivet inside the Taillight Assembly connected dissimilar metals together. When I buffed it up with 'Scotchbrite', the problem disappeared. It made no sense 'logically', but rigorous Troubleshooting - assuming nothing - saved the day. If it is a bad Taillight Ground, as my pal also had on his 15' '88 Fleetwood, this method will find it.

This is the only thing that i have not done, I will do this tonight and give it a try.

[Dunner]

Originally Posted by Djanzen

This is the only thing that i have not done, I will do this tonight a try.

Not that is mattered, but I just found a table lamp socket with this condition. Didn't make a difference in the lamp. I was just testing the ohm zero reading on my new Fluke.