Trailer light pigtail - LCD's - FYI - Ford Powerstroke Diesel Forum
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post #1 of 1 Old 09-02-2010, 03:51 AM Thread Starter Fanatic
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Trailer light pigtail - LCD's - FYI

As an FYI:

I was having problems with my trailer lights. Whenever the headlights or parking lights were on the turn/brake lights would also energize. If the headlights were off, the turn, brake lights worked fine. In other words, on the 4 prong plug ( ground, running, L Turn, R Turn) both L and R Turns would show 15V when the headlights turned on.

I took it in to the dealer who replaced and checked all the relays and fuses.
It turned out to be the aftermarket LED's I was using in my trucks rear tail lights. When he replaced them with regular bulbs the problem vanished.
I would not have believed it if I did not see it myself.

Apparently the trucks computers were sensing too low a resistance in the lights and defaulting to an all on situation.

Luckily I have a very cool dealership ( Mod friendly too! - I do not have to return to stock for maintenance like this) and he did not charge me for the tech work.

Moral of the story: If you are having weird issues with your trailer lights and have aftermarket LED's installed in your truck, try replacing them with factory incandescence and see if that solves the problem.

2010 F250 6.4 Black Pioneer Nav, Jl, Memphis audio Subs, Memphis Hybrid Amp.
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