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jrvly1976 · 05-12-2009, 02:46 PM

The running lights do not work on my 1975 31' Sovereign. The turn signals, backup and brake lights work. I have traced the current to the plug going into the trailer. I have checked the fuse box and see no blown fuses. Can you give me any help?

Joe V.

wkerfoot · 05-12-2009, 02:51 PM

Quote:

Originally Posted by jrvly1976

The running lights do not work on my 1975 31' Sovereign. The turn signals, backup and brake lights work. I have traced the current to the plug going into the trailer. I have checked the fuse box and see no blown fuses. Can you give me any help?

Joe V.

Joe,

Check the fuses with a continuity tester, sometime a bad fuse will look good.

Bill

extiger · 05-12-2009, 03:12 PM

Don't forget to check the fuses on the tow vehicle. I had a problem a while back where some of the trailer external lights worked and others didn't. After numerous trailer checks, I checked the TV fuses and low and behold.

Mexray · 05-12-2009, 11:16 PM

You mentioned that the 'running lights' don't work...as they are on the same circuit as the Tail Lights, I'm assuming that the Tail lights don't work either???

Yes indeed, check the fuse for the Tail light circuit in the AS...

If you have current in the plug going into the trailer - plug into the trailer, turn on your TV's Tail lights, and check to see if you have 12 volts at the 'inlet' side of the fuse in the trailer for it's Tail light circuit...

If you have 12 volts there - install a new, known good fuse and check the 'outlet side of the fuse in the trailer...if the fuse doesn't blow, and you don't have any Tail and marker lights illuminated in the trailer - you've got bad connection between the fuse panel and the first junction in the wiring up front where the wiring goes up into the marker lights (your fuse panel is up front, isn't it?)

Now if your fuse blows in the above testing, you've got a 'short' to ground somewhere in the Tail light wiring - a rear 'BEAR' to find...

I had THAT PROBLEM...

...as the wiring runs overhead along the vents, I attacked the fwd vent to get to the wiring - found the Tail light wire, and cut it...found voltage OK forward....rehooked wire and went to the rear vent to do the same - voltage OK forward of the 'cut' again...

Now I attacked the curbside tail/stop light assembly, as that's where the wires come down from the roof (in our 78 AS)...cut the wire to the rear markers - they were OK, isolated both LH and RH Tail lights - they were OK...THEN found the two wires going down to the License plate light ---WOOPIE - found the short!!!

Took the Lic Plt light socket apart to find that the 'hot' lead was frayed and touching to ground...They use a two contact bulb/socket in that fixture, and it's easy for the 'hot' lead to messed up over the years...I spent several hours on this problem and could have fixed it in 10 minutes if I'd known to check that darn Lic Plt light FIRST!!!

I replaced that Lic Plt bulb with a hard wired LED module to cure that problem forever!

In your case...you might want to open up the LH tail/stop lights to check where all those wires are hooked together, checking each one at a time to see if there's a short - that's assuming you have the 'blown fuse' type problem...

Good luck...it's a real pain to find this kind of problem, sometimes...make sure all the wires in your fuse panel are sound, clean and tight...

drag'nwagon · 05-12-2009, 11:29 PM

If you still have the round pin plug on the trailer side of the umbilical cord, check that the round recepticle has not "slid" backwards (it happens when the plug gets worn out). You potentially can slide it forwards and it will make contact again. Open the plug side and push all the brass tabs towards the conection side and try again. This happened to me but with the brakes. If this is the issue, than replace the plug and probably the entire umbilical cord immediately. It will happen again but next time it may be your brakes!

Frank's Trailer Works · 05-13-2009, 04:32 AM

Up under the hood is another fuse box. In it is a trailer relay and a trailer relay fuse. One of those is bad. I spend 10 hours dealing with "what did I wire wrong" to find that out. This fuse box is generally not listed in the owners manual. I had brake lights, tail lights, and turn signals, but no electric brakes or running lights. It all works now.

Mrcrowley · 05-13-2009, 05:17 AM

Best way to weed out problem is to follow the wire back through the trailer from the TV..

1) Do what forum says first then Check for connection from TV to trailer
2) Check from trailer hook up to fuse box
3) check wire from fuse box out
4) (Fine wiring diagram ) Follow wire through trailer .

Mrcrowley · 05-13-2009, 05:27 AM

Quote:

Originally Posted by jrvly1976

The running lights do not work on my 1975 31' Sovereign. The turn signals, backup and brake lights work. I have traced the current to the plug going into the trailer. I have checked the fuse box and see no blown fuses. Can you give me any help?

Joe V.

DO you have wiring diagram for trailer lights?

I would get one go way to trace wires.

Frank's Trailer Works · 05-13-2009, 08:25 AM

Take a battery and connect two leads to it. Put the negative into the proper slot and you can touch each point to see what happens. I strongly suspect you will find everything works. If that checks out, you know it is the truck. I just went through this last week and it was the trailer relay up under the hood.

jrvly1976 · 05-13-2009, 06:20 PM

Thank you for all that responded to my first message!

I tracked the the current from the TV trough the pigtail in to the trailer and checked the current into the fuse. There was no current on the trailer side of the fuse. Went and bought a new fuse, installed it and rechecked the current. I had current on the trailer side of the fuse but no tail lights and no running lights. The fuse did not blow. I don't understand it!

I turned on the Tow Vehicle lights, check the TV plug for current, traced the current trough the connecting wire into the trailer, had current on both sides of the fuse located in the front of the trailer that is right behind the the 7 point plug. The fuse does not blow but the current is live and no tail lights or running lights.

Can someone tell me where the next junction box is located? This is the black wire leading into the trailer.

Thanks again for all your help!

Mexray · 05-14-2009, 07:45 AM

Per my notes above, with 12 volts (pos) on both sides of the fuse - I would believe you have an 'open' circuit between the fuse box and the first 'junction' or connection of the Tail light circuit....

I believe your Tail light wiring goes from the fuse box, up into the forward overhead wiring harness where it travels aft in the ceiling, then down to the rear, curbside tail/stop light location.

The first 'junction' after the fuse box should be where the connection for the forward marker lights is made, in the ceiling, at the front of the trailer...and since these marker lights don't work, I would assume your 'open' is between here and the fuse box, itself...

Check the wire for this circuit carefully where it attaches to the fuse holder - is the connection clean (bright copper wires) and secured properly??? You may wish to wiggle it and try to tighten the screw holding the wire. Check to see that a previous owner hasn't modified the wires for this circuit, or added something that has affected this circuit...I would hope your problem is near the fuse panel somewhere...

If everything in the fuse panel looks 'OK', you might have to go to the lengths that I did in the overhead to check for a good circuit, as I mentioned in my previous post...

extiger · 05-14-2009, 01:01 PM

When I was messing with a similar problem (turned out that a TV fuse was blown) I checked several times the trailer's 12V fuses and found that I had to pull each one to determine that it was good. I replaced all the trailer fuses with the slightly more expensive fuses that light up when blown, so I can now just open the trailer fuse box and see their status.

Frank's Trailer Works · 05-14-2009, 04:00 PM

thats kind of what I said twice now. I sure felt foolish finding it was such a simple fix...

Mexray · 05-14-2009, 06:56 PM

He has said that he has 'current' at both sides of the fuse in the trailer...I believe it can then be assumed that the TV has nothing to due with his problem...

He then must have an 'open' in the circuit from the trailer's fuse panel - to the tail/marker lights, somewhere...finding it is another story...

mello mike · 08-14-2009, 12:39 PM

Had this problem with my running lights and last night found out it was my Excursion while I was troubleshooting my pigtail. Had a blown 20amp fuse all along.