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I got a Tekonsha P3 + harness for my 2002 F250 to replace an older model Tekonsha. But the plug/play harness doesn't fit the connector under the dash.
The old one was hardwired so I figured, "No problem, just cut the old one off and wire up the new one."
But I stupidly snipped all 4 wires at the same time. It caused a short and sparks and swear words flew.
I checked the fuse and the towing lights fuse was blown. I changed that and wired up the connector.
But when I hook up the new controller it doesn't work. A Tekonsha P3 I have on another truck won't work either. The new controller works fine in the other truck, so something is wrong with my wiring.
Could there be an inline fuse somewhere else for the trailer wiring other than the one in the fuse box?
under the hood there should be some relay's as well consult the owners manual for which one.
Bingo!
There wasn't anything under the hood, but you did prompt me to read the manual's fuse section a little closer. It turns out there's more than one for the trailer, and I blew both. I had changed the little yellow 20A one but missed the large, square pink 30A fuse. Once I changed that, all's good.