How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Gary Your Own Question
Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 17155
Experience:  15 years GM master tech
Type Your Chevy Question Here...
Gary is online now
A new question is answered every 9 seconds

Chevrolet Express 3500 LS: Having trouble finding +12v signal

Customer Question

Having trouble finding +12v signal at brake switch to install a brake controller
Submitted: 2 years ago.
Category: Chevy
Expert:  Gary replied 2 years ago.
how many wires are what colors are at the brake light switch connector ?it should look like this with these 4 wire colorsdoes the purple or the blue/white show 12 volts when you step on the brake pedal ?
Customer: replied 2 years ago.
There are four wires, none of them have voltage present???
Customer: replied 2 years ago.
But when I plug in the connector, and turn on the key, the brake lights work???
Customer: replied 2 years ago.
Is there something different about the 2011 Express? I have installed brake controllers on my previous vehicles, but they were all chevy or ford trucks.
Expert:  Gary replied 2 years ago.
one of those wires has to show 12 voltsfor the brake lights to work2011 chevy express that plug i showed you are the wire colors the same as your van ?
Expert:  Gary replied 2 years ago.
how many wires are in your connector ? 6 or 4 ?this might be a late 2011 and actually have 2012 wiring in it
Customer: replied 2 years ago.
I have a trusted and tested voltage meter, there is no voltage present at the plug. Someone told me that there is some kind of relay somewhere that this van uses to turn on lights, is that right?
Expert:  Gary replied 2 years ago.
if you have 6 then you are correct there will be no 12 volts at the brake switchthe BCM controls all the brake and lightingyou need to get to the BCM # ***** in the first picture and locate connector X5 as seen in the second picture and locate terminal # ***** a light blue/white wire in that connector and that wire should show 12 when stepping on the braketap into that wire for the brake signal for the trailer brake control