Flashing red dash light, Trying to troubleshoot light, Options

[Jamie]

...I know it references master cylinder/brake and parking brake operation. I disconnected lead to master cylinder and the light still flashes, so this seems to indicate defect in parking brake switch operation if I'm correct. I depressed the brake switch contact all the way down by hand without any change in flashing. Do these switches have a habit of failure, and I see no wire access as it seems to be well hidden under carpet. Is there any easy access to that wire without tearing open carpet in my original condition interior? (IMG:style_emoticons/default/hissyfit.gif)

[Superhawk996]

Happy to help you troubleshoot it but you need to use Multimeter. Do you have one?

[Jamie]

Happy to help you troubleshoot it but you need to use Multimeter. Do you have one?

Have multimeter, don't have info about access for places to test?

[Superhawk996]

Happy to help you troubleshoot it but you need to use Multimeter. Do you have one?

Have multimeter, don't have info about access for places to test?

Here’s a simplified schematic from Spoke



The circuit is basically a switched ground.

So when either the park brake switch or the master cylinder switch are closed and connected to ground - the warning light begins to flash.

The wire coming up from the master cylinder switch and parking brake switch is brown / white (early) or brown / yellow (late). There may be two wires tied into a single spade (I don’t have a late car) at the back of the bulb. If there are two wires into a single spade - we will have to get more creative to determine if it’s the parking brake switch or the master cylinder switch causing the issue (let’s deal with that later) What year is your car - assuming late based on you saying brown/yellow.

These wires can be found on the back side of the gauge connected to the lamp.

Use the multimeter to measure resistance between a good chassis ground and the Brown & yellow wire. Should be infinite / open assuming your master cylinder and/or parking brake switch doesn’t have issues. If it is near zero ohms - that is going to cause the warning lamp to come on and flash.

The other side of the bulb ought to have a wire with three colors (brown/green/white - late) which is the 12v(pulsed) feed that comes from the flasher relay. Don’t worry about that for now - only mentioning it to help you identify which bulb and wires you are looking for.