Trailer Wiring on Expedition problems

I have a 2000 Expedition. I am using the flat 4-Prong plug that was installed from the factory. About 2 years ago, I took it to the dealership and had the last 3 feet of wiring replaced. It is a seperate harness that is near the spare tire to the bumper where it is mounted. It was replaced just because the little cover tore off that keeps dust and bugs out of the connectors.

When I got it back, my trailer lights didn't work right. When you had your hazzards or turn signals on, the lights worked fine. If you hit the brake, the left one stopped. Took it back to the dealership, where of course they found nothing. Blamed it on my trailer, even though it worked fine on the other car, and fine before they replaced the wire. Well, after 3 trips to the dealership, I unpluged the harness and plugged it back in. Wha-Lah.. it worked.

Until now.

Now, if I have the trailer plugged in, the turn signals work, as long as the parking lights o brake lights are not on. What happend now? I have jumped wires trying to solve it, unhooked the ground from the harness and established a new one, I can't find any problems. All the lights work perfect as long as the are tested seperately. If you try and plug in a real tester, it fails. Think its the plug again?

I only launch is salt water but it has only been submerged once.. recently.. oh, like last weekend.

think the salt water could have damaged it?

Reply to
Ron
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It seems like you've been through the truck wiring so I'm going to suggest you check the trailer wiring. Just because it's fine one day doesn't mean it will work the next. Specifically I would check the ground on the trailer.

Since you are having many troubles I would also suggest that you buy a few light bulbs and solder up a test rig for the truck. This will let you know without a doubt that the truck wiring is bad or good. I had similar troubles once and actually made the test rig with wires long anough to reach the cab. I drove around for a week with the test bulbs within sight at all times. I was able to determine that the truck wiring was faulty. It worked fine 99% of the time. The other 1% were the times when I needed to tow.

Andrew

Reply to
Andrew

Without going into it too much, sounds like a bad connection. Bad connection + trailer -tend- to = bad ground connection.

Funny how "leaky" electricity doesn't drip on the ground so you know where to look like water does. ;)

That's my backhanded way of saying... "do yourself a favor and get a meter and learn how to use it, you won't regret it for a minute" -alvin

Don't know how to use it? Get back on here! :) Me and whoever else will volunteer will do our best.

Alvin in AZ

Reply to
alvinj

"Funny how "leaky" electricity doesn't drip on the ground so you know where to look like water does. ;)"

That's great!

Good advice Alvin.

Norm

Reply to
Norm

OK, went back out there. Disconnected the ground (from the wiring harness under the truck), and all lights go out. Used a 6/12 volt tester, just to the connector at the end and before (where the last 2 feet plug in) and all works fine. PROBLEM>>> I only have ONE terster that is a pen tester (alligator clip to the frame, pointed and in connector to light up pretty light inside pen) All 3 work fine, at all ends.

Problem comes when all 3 are tested simitaneously (ya ya, I spelled it wrong) with the cheap little plug in testers that test all at the same time with the 3 led's in them.

I guess next is to buy 2 more pen testors and/or test my cheap plug tester on someone elses car.

Any other clues why it would override the turn lights when the tail lights come on?? Ground seems fine, fuses all a go....

Halp!!! before I get a ticket :) Ron

Reply to
Ron

Well, it's definately the truck then. I would keep testing up the line to find the problem. I would guess that the last connector is faulty or that you have a broken wire. If you don't mind spending a few bucks why not buy a trailer wiring adaptor (not the Ford one). Get the one that plugs into the factory wiring loom using a T plug. If it doesn't work right you can always return it.

Andrew

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Reply to
Andrew

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