Troubleshooting Curt Trailer Wiring Kit for 2001 that Won't Power On

Updated 04/22/2025 | Published 04/21/2025

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(97)

$66.73

12 Gauge Wire - Black Primary - Per Foot

(30)

$2.02

Question:

I have a 2001 Tundra and recently purchased the Curt C55378. It isnt working after I installed it in my truck, but I believe the issue is on the truck side. The center pin on the Curt connection that plugs into my truck seems to connect to a black wire in the center of the trucks wiring harness. Should I be getting constant 12v power from that center pin/black wire when the truck is on/running? And if so Im not getting anything to that connection/wire... any chance you have a wiring diagram for an 01 Tundra or anything specific I should check? I already checked every single fuse in the truck... trucks lights work fine.

asked by: John M

Tundra Wiring Harness
(click to enlarge)

Expert Reply:

Hey John, yes the black wire pin on your 2001 Toyota Tundra should have 12 volt power on the Curt 4-way trailer wiring kit part # C55378 as this is what provides power for all of the trailer wiring circuits. If it's not active and you've checked all fuses and relays related to it then there's got to be some wiring issue on the truck for that circuit which will be challenging to track down. I would just run a wire from the battery directly and splice it in for the black wire and bypass all of that headache. We sell 12 gauge wire by the foot with the part # 12-1-1.

expert reply by: Jameson C

John M.

4/22/2025

Should that be constant power or only when the key is turned on? I just want to make sure I'm not draining my battery when it's sitting?

Jameson C.

4/22/2025

@JohnM It can be either way. Some vehicles have it on all the time and others will only have it on when the key is on. Unless something is connected to that circuit and actively drawing power it won't affect your battery at all so either way you wouldn't have to worry about that.