Need HELP with electrical issues
 

I'm having problems with the brake lights on an '89 Carrera Cab. The problem is I only have brake lights when the headlights are on. I've checked the connections on the fuse block and both switches on the master cylinder. Those look fine. With the headlights OFF, when I touch the brake pedal I can hear a relay click and lose power at the fuse. I'm baffled:confused:. Also can someone explain the elements in the red boxes on the attached schematic? Specifically T9 and T10 and where might I find these on the car.
TIA!
http://forums.pelicanparts.com/uploa...1329965449.jpg

wild guess...head LT switch? is that in common with flow?

Replaced with new and I'm satisfied it's plugged in correctly. As is the turn signal switch.

The relay click is interesting I could be wrong but I dont think there is a relay in the brake light system. Im wondering if some one upgraded your headlights to relay control and ran the brakes through the relay as well.

It would sound as if your brake lights are powered of the same junction as your head lights. May be an issue in the fuse box, may be a hack wiring job from a PO. I would trace all your head light wires and see if there is any thing our of the ordinary there. Then trace the wires around the brake switch. I would also try and find that relay and figure out whats going on there.

Regards
Dave

ding ding,,after some thought I think that is the answers

you say you have brake lights when the HL's are on.?

when the HL's are on, and you press the brake pedal, the lights get brighter, or, you just have tail lights when the HL's are on? these are 2 seperate circuits is the reason i ask.

check the connections related to the brakes. make sure they are clean.
with a test light, check for power at the brake switch, fuse, connections and the the brake lights socket. since both do not work, look for aomething common.

make sure you have the light connected to a good ground.

I agree with the previous post I would check the headlight relay wiring.