Jim10517

Does anyone have the wiring diagram for the brake light switch (switch on brake pedal)? I could use a copy. Thanks.

52merc

Don't know from your signature which engine you have so see the attached. Hope these help you out.

Jim10517

Awesome. I have the 3.5 Eco.

If I'm reading this correctly, When the pedal is pressed, power is sent to the VT-WH wire which causes the brake lights to light. Am I correct?

Thanks.

Gordy49913

Partially correct. The brake position switch tells the BCM you need the brake lights turned on. The BCM then turns on the brake lights. Do not hook a wire to the brake light switch. The circuit is not designed for that. The BCM will detect an overload on that circuit and turn it off.

Jim10517

Gordy - that's what I get for not being specific. Brake pedal switch completes the circuit between the BR-RD and VT-WH to tell the BCM to turn the lights on. So, a jumper between these two wires would do the same. Correct?

Not looking to put a load on the VT-WH wire.

Gordy49913

I would say yes.

52merc

That is correct. Jump between Pin-1 and Pin-4 of Connector C278.

ajazf150

Maybe this thread is a little old but I've just run into something maybe similar. Had to replace master cylinder and power booster and noticed brake lights stayed on. So I pulled out the brake switch to try to adjust it and now brake lights never come on. I checked resistance of switch at pins 1,4 and always open regardless of whether switch plunger is pushed in or out. Then shorted connecter C278 pins 1,4 and brake lights illuminated. So I bought another switch. Exactly the same situation. Also pins 2,3 on switch are shorted regardless of plunger position. Running out of ideas as this seems like a simple circuit but things aren't adding up for me. Any ideas? thanks

allanbradl

Hi, Did you ever solved your problem?

ajazf150

I was able to extend the switch plunger a bit but I'm still not content with the solution. I really need to figure out how to extend the brake booster plunger somehow as the cruise control won't deactivate with a reasonable amount of brake pedal pressure.