Installation of Primus IQ Brake Controller Causes Traction Control Fault on a 2006 Buick LaCrosse

Question:

I just wired up my Primus IQ to my 2006 Buick Lacrosse. This car has a brake Pedal position sensor with a black LOW REF, Lt Green Stop Lamp Switch Signal and a Gray 10V Ref wire. I hooked the Controller red wire to the Lt-Green wire but now I get a Traction Control Failure. When I remove the controller the fault goes away. Have you ever seen this before? Any thoughts on how to correct this?

asked by: Bernie A

Helpful Expert Reply:

There are some vehicles that have this or a similar issue called a low-side switching system and you cannot tap into the brake switch wiring when installing a brake controller because of it. If you do not have a wire on the brake switch that shows 12 volts of power only when the brake pedal is pressed then you will need to get a dedicated brake light signal elsewhere. Typical places are:

The CHMSL fuse, if it is the only function on the fuse. Use the owners manual to find its location.
A third brake light.
The body control module.

The body control module would be difficult because there are some many pins and wires, you would need to have a diagram of it to determine which pin or wire is a brake light only circuit.

expert reply by: Michael H