brake lights are on on on

P

pick

Member
brake lights are on whenever the battery is connected. the pedal linkage has been checked all out, brake switch has been replaced. whenever the battery is connected the brake lights are on even when the wires are disconnected from the brake switch. what's up? any ideas? where do I start?????
 
Has the lights been worked on? Did this just start?

Take a volt meter or test light and check each side of the switch. One terminal will have voltage to the frame the other sould not. If both are hot remove the wire heading to the rear of the car. Check the terminal you removed the wire from it should showing no voltage to the frame. If it still is hot = bad switch. If the switch is dead wireing wrong. Check this and let us know. Pm me if you wish, Phil
 
i'll check the wiring/switch tomorrow night as you suggested obviously electrics are not my forte.....
 
fyi this is a new project I just purchased and it didn't have this problem until last time I drove it
 
pick said:
brake lights are on whenever the battery is connected. the pedal linkage has been checked all out, brake switch has been replaced. whenever the battery is connected the brake lights are on even when the wires are disconnected from the brake switch. what's up? any ideas? where do I start?????
Click to expand...

Can't be the switch, as it's now out of the circuit.
 
Tom Wesenberg said:
Can't be the switch, as it's now out of the circuit.
Click to expand...

Oops I miss read the original post. Didn't notice wires were disconnected from switch. Would be time to trace out the wires from the brake light to source. Sorry for the senior moment,Phil.
 
sounds to me like the brake lights are being fed by the tail light circuit. Is the headlight switch off or in park position?
 
qtcoupe said:
sounds to me like the brake lights are being fed by the tail light circuit. Is the headlight switch off or in park position?
Click to expand...

I was thinking the same thing. Something has to be crossed for the brake light to be on with the switch out of the circuit. Maybe the two wires are crossed at the connection over the rear axle. That plus the switch being in some position other than off.
 
will this help? it's for 30/31
 

Attachments

  • img395.jpg
    img395.jpg
    110.2 KB · Views: 84
Brake light on when disconnected from the switch is a challenging mystery.

You have to find out where the electrical energy is coming from. It is not possible for the light to be on without electricity from somewhere. Somehow, someway, electricity is getting into the brake light wire.
My guess, strictly a guess, is the wiring bundle at the bottom of the steering column is somehow crossed or shorted. It is the only place I can think of that would supply the current, absent a major mistake. The repo switches are not very good at keeping the connections separated, but even that does not make much sense if the switch is unwired.
Assuming everything else is off, and double check that assumption, one way is to get a pal to watch the light, and start dis-connecting the wire, starting from the wire into the light and go forward, until it goes off. Or, by yourself, trace it with a voltage and continuity tester from the light forward.
I look forward to seeing the solution. Please keep us advised.
 
If he's got lights with the switch pulled from the column there could be a short inside the harness from the battery wire (on the starter) to the tail light wire. The harness is the only place where everything is together. The short could also be where the harness ties to the switch contacts.

Rethinking, there is also a hot wire in the harness to the brake light switch - those two wires could also be shorted inside the harness. This could be tested by removing both wires from the switch and measuring if there's voltage on both - only one wire should be hot.

This is an interesting puzzle!
 
Do you have turn signals wired into the car? The turn signal uses the original brake light wire to flash the brake light on one side, plus an additional wire not in the original loom to flash the brake light on the other side. The output from the brake switch should be routed up to appropriate wire in the turn signal wiring harness so that when you step on the brake, juice is sent through the turn signal switch and out to the two wires to the brake lights. I'd be that somehow the turn signal wiring got crossed up so that the wires for the brakes are always hot.
 
You must log in or register to reply here.
Back
Top