7 way plug issue - R turn and brake

[Raist11]

Good morning, hoping for some tips on this issue. Its an old 1990 Triple E and I am towing my Jeep behind. Plugging in the lights I only get left turn and brake, no right side at all. I even tried my magnetic set of lights with the same problem.

I assume it wouldnt be a ground issue because the left side works fine and there is only one ground blade in a seven way plug. The seven way plug looks okay.. but what am I missing here? Thanks for any input.

Sorry if this reads like ****. I'm typing this on my phone so not the best method for myself.

[Raist11]

DrewE wrote:
It could just be a loose or broken wire etc. for the right turn/brake light line, presumably on the tow vehicle side of things.

If the Triple E has separate turn signal and brake lights there's some sort of a converter or other circuit to translate the signals for the trailer connector; that could conceivably also be bad/malfunctioning. I would hunt for a bad connection first, though.

Yep, looks like this was it. At the junction box the wire coming out of the adapter had a crack.

[RoyB]

I just this sent up the page here for a similar trailer safety lights problems.. Maybe my info will help here as well...

I carry one of the 7-way Trailer Connector testers - Got mine from ETRAILER but I have seen them in some auto parts places...



When you plug this into your truck trailer socket then it only see's the truck side. If the small LED lights work normal then there is not problem with your truck side...

Also on my 2010 new F150 Truck I had to install a RELAY and a FUSE that was in a unmarked plastic bag. This has to do with the TRAILER CHARGE DC voltages coming from the truck. It is only present when the truck ignition Key is turned ON. I found this bag in the truck glove box with no info with it. You can see where it plugs in by looking in your manual marked TRAILER CHARGE...

Trailer grounds and sometimes shorted out bulbs cause weird problems...

By eliminating the truck side being the problem it helps speed up tracking the down the problem on the trailer side...

ETRAILER.com has good info on its site to help you along...

Roy Ken

[Farmerjon]

There are 2 ways a 7 way plug could be wired. The other way would be for utility trailers with the center pin wired as auxiliary power.

[Raist11]

It may be just a bad wire. I rigged up a test light with a spare 1157 bulb and found a crack in the wire sleeve/insulating the flashers seem to work.

Thanks.

[DrewE]

It could just be a loose or broken wire etc. for the right turn/brake light line, presumably on the tow vehicle side of things.

If the Triple E has separate turn signal and brake lights there's some sort of a converter or other circuit to translate the signals for the trailer connector; that could conceivably also be bad/malfunctioning. I would hunt for a bad connection first, though.

[Raist11]

Well so far it looks like they arent fused seperate. But the manual only includes diagram for GM fuse box and says to refer to chassis manual for Ford, which I dont have. Looking online it seems they arent though.

Thanks for the 7 way diagram, I was actually looking at that one online earlier.

[ChooChooMan74]

[dockmasterdave]

Some times they are fused separately.

[Raist11]

Sorry, didnt know the c version of feces was a bad word here. 😛