Running lights and taillights out

[steven2themax]

1973 sovereign.

Everything is checked out from the TV to the end of the umbilical. Once the umbilical is plugged in there is no power to that wire for tailights so I assume that there is a short. I am pretty clueless on electrical stuff.

If there are bulbs out in one of the running lights will all of them stop working?

Should I open the tail light assembly and check it out. The tail lights will work when the hazards are on.

Thanks a bunch.

[mello mike]

When you say taillights do you mean stop/turn lights? Or are you just focusing on the running lights?

I would try applying 12v power to the running lights pin which should be at 11 o'clock on your 7-pin connector. What I would do is run a jumper wire from the pin at 1 o'clock (this is your trailer battery charge line) to the one at 11 o'clock (which is your running lights). First make sure you have power at the trailer battery charge line. Take a volt meter to it to ensure you have 12v there. If you blow a fuse after apply power to your running lights you have a short in the running lights wiring somewhere.

[wasagachris]

There is an inspection cover for the trailer end of the umbilical connecter just under the front couch. Remove the cushion and plywood base to get at the cover. Open the cover and check for a broken wire or loose connection and check for power for the running lights on the green wire. If you jhave power there then you need to check the taillights.

[steven2themax]

Sorry let me clarify.

working: brake lights, turn signals, backup lights.
Tailights (for night driving) not working. Neither are the running lights (any of the lights running around the outside of the trailer)

I have run power through the umbilical and it works for the tailights. When I plug it in and take the cover off of the 7 way inside then I no longer have power at the green wire for tailights.

What are the most common reason's for a short?

[mello mike]

If you have a short in your running lights, as you suspect, then you likely blew a fuse in your TV for your running lights. Are you sure you have 12v power going from your TV to your running lights?

[Jammer]

Two possibilities.

Some TV have a circuit breaker for tail/marker lights for the trailer (mine does) and so yes if there is a short it will shut off until you unplug it and wait for a while.

If you have a short it's going to be a pain finding it. Usually a visual inspection works best, looking for wires that are scraping against something metal, or obviously damaged. Failing that you can start disconnecting stuff until the problem goes away.

The other possibility is that you have a wiring problem in the TV and it isn't really puting 12 volts on the tail/marker circuit. You can check it with a test light to be sure. That's more of a sure-fire check than a meter because the power draw of the test light will catch problems that the meter won't.

[wasagachris]

I think you are using the term Short when you mean no connection. A short circuit is the power wire going right to ground against the frame/shell etc and indeed you will blow a fuse. If you have no power then you have a broken/loose connection/wire etc causing an incomplete or open circuit.
If you have confirmed that you indeed do have power to the umbilical for the running lights. Disconnect the umbilical from the trailer and run a jumper from the charge line(larger blue wire) on the inside of the 7 pin trailer connecter to the green wire and see if you have running lights. If they work the problem is no connection from the umbilical to the trailer 7 pin connector.

[Splitrock]

Hi Steven,

First off I'd look for fuses and test them.

If it's not a fuse then: You have three elements. You need to separate them. Test them while they are not connected.

#One is the tow vehicle. Check the trailer cord connection out with a tester. If the tow vehicle is all okay:

#Two, is the umbilical cord. Test that with a power source like a small battery charger, and a test light with the cord removed from the tow vehicle and removed from the trailer as well.

#Three is the trailer wiring system. Unplug the 110 volt cord and remove the battery connection. Test the 7-way plug with a power source like a small battery charger, a multi-meter, and a test light.

My tail/clearance lights weren't working on my trailer. A test with a multi-meter at the 7-way location inside the front of my trailer indicated a dead short. I replaced all the clearance lights with LED lights. I replaced all the bulbs in the rear lights even if they were working. I took every socket out and cleaned and polished the contact points with a Dremel. I replaced one rusty socket at the back up light location. When I powered it up, they all worked. I don't know what the problem was, but I know where it was.

The brake lights and flashers are on a different circuit.

My approach to solving my light not working problem was not to find the problem. My approach was to eliminate all sources of problems in the light circuit. By doing that, I found and fixed the initial problem. A broken bulb with a filament laying down can cause the problem. A bad socket can cause the problem.

Gary

[SilverRanger]

I concur on Gary's "bad socket/filament" suggestion. A similar thing happened to me a few years back. The AS was still under warranty, but I didn't relish the idea of the 150 mile round trip to the dealership. I checked the fuses, and used a multi-tester to the best of my (limited) ability to test the circuits I could access. I could only determine there was a short somewhere in the trailer wiring. So, I began to methodically remove all the clearance light lenses to see if there was something obvious. About half way through, I noticed a burned out bulb on one of the rear lights. The socket (as did all the rest) looked OK, so I just replaced the bulb. The lights have been working ever since.

Best of luck to you in your search.

[steven2themax]

Thanks everyone.

I do have a 7way tester for TV which checked out. A mulitmeter at the end of the umbilical also tested good. I will start replacing bulbs and cleaning connections.

thanks

[wasagachris]

Stephen if you have not one of your running lights working check the 7 pin connector as I said earlier. I highly doubt that each and every bulb or socket is bad. try jumping power to the green wire and see what lights do work.

[TG Twinkie]

If you have a battery charger, use it to test your trailer tail and marker lights. Simply connect the black clamp of the battery charger to the ground terminal in the j box then connect the red charger lead to the tail light terminal. If the meter on the charger pegs and the charger shuts off momentarily. Most have what they call a "crowbar protection system" and will shut down if there is an over current situation. Use a charger that has a max capacity of 10 amps. By using the charger you don't have to be connected to the TV and you won't go thru a box of fuses trying to find the problem. If you do have a short, it could be in one fixture, so remove the bulbs from each (all) fixtures. Then connect the charger as stated above. If things look normal, the wiring is probably OK. The next step is to start reinstalling the bulbs one at a time until you cause the charger to "crowbar". This will be where your problem is. Good Luck!

[steven2themax]

All right so I was going to replace some bulbs and I looked at the condition of the clearance lights etc and decided to replace all the clearance lights. So all of the red and yellow lights fixtures are brand new installed and still it is not working.

I have checked all the fuses. I have repeatedly checked everything up to the end of the umbilical where it connects to the trailer and it is good.

if all else fails I will have to buy extra tail lights and hook them up to the 4 way on the TV but there has to be another solution.

[steven2themax]

I took the 7 way @ the trailer apart and all looks good, but I am considering replacing it. There is no evidence of corrosion or loose wires.

I tried jumping it with a battery charger but i don't think i was doing it right because I couldn't get anything to come on. I attached the red to the wire I wanted to test (green/tailights) and grounded the black to the trailer frame. Not clear on the correct way to do this.

[mello mike]

Steven,
You were doing it correctly. Try another wire like the brake lights or back up lights and see what happens. If they work, then you have an open or short in your running lights circuit.

[steven2themax]

Mike the reason I thought I wasn't doing it correctly is because I tried the exat same jump on the other lights that had been working and I couldn't get them to light up with the battery charger. Can I use just a 12v battery?

[Diesel1]

You can use a battery. Remember it is sometimes hard to get a good ground. Once you are sure your ground wire is good then you can check each circuit. Adios, John

[steven2themax]

How would I ground it properly if I use a battery?

[Diesel1]

I would ground the battery negitive terminal to the trailer shell. Or to both the shell and frame.A jumper wire with an aligator clip will work, or clamp, screw or vise grip the wire to the shell. Also you may want to hook to the ground on the 7 pin connecter to make sure your tow vehicle to trailer ground is good. Bad grounds are very commen on these old dogs. Adios, John

[steven2themax]

OK reading through some other posts I found the last light I didn't check/replace was the license plate light. Will check that one out first thing am