2006 S40, brake lights won't go out. Changed the brake light switch and checked plunger action. Switch operation okay. All 3 brake lights stay on. Does anyone have an idea whats wrong please?

 

sounds like you could have a bad ground point or a short allowing voltage to bypass the switch. When you replaced the switch, did you check voltage on both pins to make sure it doesn't need adjustment or do the lights go off when you disconnect the wires to the switch? Also, do the brake lights go off when you remove the fuse (check owners manual but should be #57 in the passenger compartment)? Do the lights all go off when you disconnect each of the connectors for the tail lights and center lights? If so, you may have a short inside the light housing or connector.

Finally you may need to trace wiring (ugh...) - check out volvowiringdiagrams.com for junction points etc.

 

Does the CEM control the brake lights? or does the wiring just go thru it from jack to fuse to jack?

 

yes, see http://volvowiringdiagrams.com/volvo...%20Diagram.pdf page 73.

 

So, the only thing common to all 3 brake lights is the fuse F57, Brake light switch and the CEM. All 3 lights are on constantly. Its probably not wiring from the CEM to the lights since the 3rd brake light is wired differently from the 2 tail lights. That would leave the switch wiring and the CEM itself or a bad jack connection at the CEM. Yes?

 

With the brake pedal released, do you have power on the orange wire from the brake light switch?

What happens if you disconnect the brake light switch?

 

Hi, i have the exact same problem. I cleaned out the ECM and checked every fuse. This seems to be okay.

I also replaced the Brake light switch (works as it should), with the switch disconnected there is power on only one wire. But also power on fuse 57 with the switch disconnected. Even with the fuse and switch disconnected all 3 Brake lights are on.

Does anyone have an idea what the problem can be?