help trailer brake wiring
Elder User
Joined: Apr 2004
Posts: 797
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From: Wickenburg, AZ
Yeah, it'll have the four-wire old design. You can get a pigtail harness for your controller. Now, if your '90 is like Dad's '92, and you don't have the trailer package, you will find that your truck is pre-wired for the brake switch signal and ground. You'll need to run two wires, the power supply and the brake controller output to a new plug at the back of the truck. I don't know if you're using a 6 or 7-way. Personally, I like the 7-way Bargman flat-pin system.
Dark blue wire will be your brake controller output signal, but It'll terminate inside the cab, I'm afraid to say. I can't help much more than that, other than to suggest you might eventually need a 12V power supply line run to the trailer plug as well. Some trailers need this, others don't. Check out the manual. if you do need one or want one anyway, I'd run them as a pair right down the factory chase on the left side frame rail.
Dark blue wire will be your brake controller output signal, but It'll terminate inside the cab, I'm afraid to say. I can't help much more than that, other than to suggest you might eventually need a 12V power supply line run to the trailer plug as well. Some trailers need this, others don't. Check out the manual. if you do need one or want one anyway, I'd run them as a pair right down the factory chase on the left side frame rail.
