Where Is Factory Brake Controller Plug On 2026 BMW X5
Updated 08/27/2025 | Published 08/15/2025
Question:
Re: Tekonsha TK62BR for 2026 BMW X5 w/303700 harness. Hopefully Tekonsha will answer E-Trailer as they have not responded to my inquiry. Per the 303700 install instructions, the factory plug is not where they say it should be and I cant find it. I do have factory tow package. HELP. and TIA
asked by: Greg T
Expert Reply:
Hello Greg, thanks for reaching out. I have heard of this before on certain new BMWs where the factory harness plugin should be in the rear cargo area but instead BMW decided to put it under the dash on the drivers side.
It sounds like this might be the case with your X5 and if so, sadly, none of our manufacturers make anything to support this plug. The 303700 harness should have the correct plug ends, but you would have like 19' of extra wire to deal with. You could try taking the harness and cutting it down to size and splicing it back together. Otherwise the only option would be to cut off the factory plug and hardwire the controller using the included 4-wire pigtail.
(click to enlarge)
Product Page this Question was Asked From
Tekonsha Prodigy P3 Trailer Brake Controller w/ Custom Harness - 1 to 4 Axles - Proportional
- Trailer Brake Controller
- Proportional Controller
- Electric
- Electric over Hydraulic
- Plug-In
- Under-Dash Box
- Under-Dash
- Up to 4 Axles
- LCD Display
- Multiple Trailers
- Tekonsha
more information >
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Greg T.
8/27/2025
Thank you! Great info and and have now found the plug under the dash area. Given the 303700 has the correct plug ends, that seems to be the way to go (BMW does not sell the male plug).