I thought 4 pin trailer brake controller plug was installed on all vehicles?

Spun Crankhub · 01-25-2021, 01:16 PM

So I am getting my 08 X5 ready for tow duty, and am wiring for an aftermarket Reese trailer brake controller. Ive got all the panels off along the right side of the vehicle, and the only harness plug I can find along the length of wiring is the 3 pin can bus plug.
At this point I am not that worried about the 4 pin being absent, and am going to deconstruct some of the loom to hopefully find the 4 wires.
Wondering if anyone else who wired their car encountered this?!

Spun Crankhub · 01-28-2021, 03:32 PM

In case anyone stumbles onto this, I routed the blue wire on the vehicle side of the brake controller to the blue and red wire on the bmw brake pedal switch using a quick connect. This wire will give you 12V when the brake pedal is depressed.

Spun Crankhub · 01-28-2021, 03:34 PM

Forgive the upside down pic, but once you pull the under dash trim off via the 3 philips head screws and follow the brake pedal up, you wont be able to miss the switch.

01-25-2021, 01:16 PM	#1
Spun Crankhub Major General 964 Rep 5,033 Posts Drives: 15 F82 SOLD Join Date: Feb 2012 Location: San Jose, CA iTrader: (63)	I thought 4 pin trailer brake controller plug was installed on all vehicles? So I am getting my 08 X5 ready for tow duty, and am wiring for an aftermarket Reese trailer brake controller. Ive got all the panels off along the right side of the vehicle, and the only harness plug I can find along the length of wiring is the 3 pin can bus plug. At this point I am not that worried about the 4 pin being absent, and am going to deconstruct some of the loom to hopefully find the 4 wires. Wondering if anyone else who wired their car encountered this?! Last edited by Spun Crankhub; 01-25-2021 at 04:00 PM..
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01-28-2021, 03:32 PM	#2
Spun Crankhub Major General 964 Rep 5,033 Posts Drives: 15 F82 SOLD Join Date: Feb 2012 Location: San Jose, CA iTrader: (63)	In case anyone stumbles onto this, I routed the blue wire on the vehicle side of the brake controller to the blue and red wire on the bmw brake pedal switch using a quick connect. This wire will give you 12V when the brake pedal is depressed. Attached Images
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01-28-2021, 03:34 PM	#3
Spun Crankhub Major General 964 Rep 5,033 Posts Drives: 15 F82 SOLD Join Date: Feb 2012 Location: San Jose, CA iTrader: (63)	Forgive the upside down pic, but once you pull the under dash trim off via the 3 philips head screws and follow the brake pedal up, you wont be able to miss the switch.
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