Trailer Running Lights Issue

[norcal10]

Hi everyone,

I recently acquired a 1979 Nomad 23ft trailer. However, I can not get any of the trailer lights to work. No running lights, tail lights, clearance lights or electric brakes. The only light that works is the passenger side turn signal. I've cleaned every light, tightened the grounds on them, cleaned the ground from the 7-way that is grounded on the trailer frame, sprayed the pigtail with WD-40, bent the prongs just a tiny bit so they fit tighter, but still the only thing that works is that passenger turn signal. Ive tested the lights with a probe tester and the only one getting power is that passenger turn signal.
Im running out of ideas. I'd appreciate any advice that you guys and gals have to offer. Electrical is not my strong point.

Thanks everyone!

[norcal10]

Hi everyone, just a quick update,
Everything in the trailer now works. I towed it out to my mechanic who had an electrician fix it. They did it in an hour or two. Rewired the 7-way and, in the rear of the trailer there were wires that were unplugged or broken. I think the mice had chewed through them. But now I have working lights, turn signals and electric brakes. Now all I have left to do before our first trip out is to get new tires, repack the bearings and fix two broken copper lines.

I appreciate all the help that everyone provided!

[LVJJJ]

bulbs work?

[JCR-1]

Easier and less time consuming to just rewire the whole darn thing..

[norcal10]

Alright everyone, thank you so much for the replies! I will start checking on this. The 2nd owner of this trailer had never used it camping. It just sat under a cover for at least 20 years, and she told me that mice had gotten in there. So ill have to assume that they may have gotten some of the wires too. Ill update once i get them working.
Again, thank you so much!

[CavemanCharlie]

workhardplayharder wrote:
Start with checking ground first.

Yup, then make sure the plug on the pickup works. Then take the plug on the trailer apart and check in there. After that if no luck you need to start working you way back. Sometimes there is a junction box mounted under the front of the trailer or maybe on the tong. Sometimes this junction box is just inside the trailer under the front seat or something. If no luck there then after that is may be easier to start over and run new wires to everything. TT manufactures often run the tail light wires in the walls and sometimes mice can get in there and eat the wires. You may should be able to run some plastic conduit under the trailer with the new wires pulled through it. Then a branch off of the conduit in the middle for the break wires and then all the way to the back and up to the tail lights. If your lucky you may be able to pull the wires up through the back wall to make it look nice. If not you just have to run them up the back of the trailer. It looks like hell but, as long as they work that's the important thing.

[classicdude]

DRSMPS wrote:
I would start at the 7-way connector and start following the wires back on the trailer. You'll likely run into several junction points which are corroded or loose. If you use your tester at each connection point, you'll soon find the faulty point in the circuit.

Frustrating - I know. Kind of like finding the loose bulb on your Christmas lights!

Good luck.

A couple days after bringing our camper home, I had this issue. Turned out to be a couple of loose, wire nutted splices in the first (and only, as far as I know) junction box as described in the above post. Seems they tied too many wires together in each splice for most any wire nut to really secure properly. No way I could break them up into smaller bundles without adding a second box. I just redid the splice, but I'll know where to go if it happens again.

[Oaklevel]

Check your tow vehicle plug first with a 12V tester make sure the plug works..... some TVs have separate fuses for the trailer plug....... When I have problems I run a separate ground wire from the TV to the Trailer.......... That's the first steps I always take then I move on to checking the trailer............. I currently own 4 utility trailers & the fiver & have for years....usually when I have troubles it is usually a ground but I did have a camper that would blow the TVs trailer fuse to the left side........next I move on to corrosion issues

[JJBIRISH]

Start with the TV and check each wire there… I betting based on what you are saying the problem is in the TV…
Use a battery grounded to the trailer and a jumper wire from the + side to test each light blade
at the trailer plug…

at way you’re not transferring a problem with the TV to the TT and confusing the issue…

[workhardplayha1]

Start with checking ground first.

[69_Avion]

After you find a centrally located junction box or connectors (probably near the front where the wires go to the front clearance lights), battery, and frame ground point, you may want to purchase a new plug and RV wiring cable to replace everything from there forward.
If you are going to buy new RV cable, make sure you get the heavy duty cable with #10 black (hot) and white (ground) along with #12 (Blue) for the brakes. The running lights, left turn, right turn and aux (usually backup) will be #14 wire. The light duty cable has smaller wires and you don't want those.
Also, remember to hook the plug up to the correct end of the wire. Yes, there is a correct end. Otherwise you will have to twist the wires around to get them to go to the correct terminals. That is not easy to do.

[wrenchbender]

You need a multimeter and some patience,along with a good 12vdc source.Locate the TT ground and go pin to pin with the 12v,and ck each lamp for voltage Also carefully look at the TT harness.I had and old friend with a Shasta that had broken rotted wiring where the harness crossed over the frame aft of the hitch.

[Bonefish]

Are you sure the plug on the tow vehicle works?
Plugging in the first time could have blown fuses.

[memgrove]

How are you checking the lights?

Your trailer is kind of old and I don't think that 7 pin connectors had a universal order for the wires back then (colors may be different today as well.

Try to use a battery with a ground on the frame and then a hot wire to the trailers plug. Test each terminal with an alligator clip or something and see what light comes on.

Then you will see what works and what does not.

[bradnailer]

DRSMPS wrote:
I would start at the 7-way connector and start following the wires back on the trailer. You'll likely run into several junction points which are corroded or loose. If you use your tester at each connection point, you'll soon find the faulty point in the circuit.

Frustrating - I know. Kind of like finding the loose bulb on your Christmas lights!

Good luck.

This is correct. The only way to fix it is to start tracing wires. Good luck.