2008 XC90 brake relay location

lmacdonald · Post by **lmacdonald** » 26 Oct 2012, 12:19

Hi,

I'm new to the forum and have a question about the brake lights which are not working on my 2008 XC90 (excpet the center LED bar light). As I was replacing the bulbs, I found what I beleive caused the problem - a brake light wire was pinched between one of the light assembly threaded mounting stud and hex standoff. So from browsing other posts it looks like I need to replace the brake relay and shunt (fuse and bulbs are OK). Is this correct? Where are these located? I found an illustration of an older model which is located in the rear left compartment but this one looks different. I hear some clicking in the console are when I step on the brake so it must be there somewhere. Is there anything else I should be looking at? I'm thinking brake switch but I don't see how that could fail from and pinched wire.

Thanks,

Larry

Post by **jimmy57** » 26 Oct 2012, 15:05

There is no relay. The lights are transistor controlled and when there is a short the circuit is shut down and a fault code is set.
You either read and erase codes or you disconnect battery and leave it disconnected for 5 minutes and re-connect and check to see if the system reset.

lmacdonald · Post by **lmacdonald** » 27 Oct 2012, 18:04

I disconnected the battery for 5 minutes and no luck. Do you think the short could have fried the transistor? If so where is that located? First thing first, I'll take it down to Autozone tomorrow and have them reset the computer.

Post by **jimmy57** » 27 Oct 2012, 22:28

The transistor is part of a whole module and is not meant to be serviceable.
AZ can't reset anything but ECM and that is not the module operating lights.

lmacdonald · Post by **lmacdonald** » 28 Oct 2012, 15:41

I just went over everything again just to make sure I didn't miss anything. I tested the bulb in the backup light sockets, checked the fuse again (there is no brake light fuse by the way, the closest was a brake switch feed fuse). I even cut, stripped and soldered the wire where it was pinched as it was a little dirty and a couple strands were broken.
So if the next step is replacing the module, which one is it and where is it located? Thanks for sticking with me on this Jimmy.

Post by **jimmy57** » 28 Oct 2012, 15:56

The next step is to the shop where VIDA is used to clear fault codes.