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?

[76-914]

Did you check the parking break switch or the wire that runs to the switch to see if it is grounded/shorted out?

[jim_hoyland]

Recently had the same. I pulled the switch for the HB, cleaned the switch and metal under the switch. Then tested the PB wire.

[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?

[Jamie]

Did you check the parking break switch or the wire that runs to the switch to see if it is grounded/shorted out?

Switch is concealed and I haven't seen any wire access for testing without tearing apart carpet. Schematic I have shows brown/yellow wire but not where is ties into wiring harness.

[jim_hoyland]

I had to remove the driver seat. Then clear the area around the switch. I removed the screw holding the switch over the hole in the cross member. Lifted the switch out and removed the small spade connector.
When that wire is removed ( and I isolated the MS switch connection), the red light went out; ground the spade and the light went on.
Being a ground circuit, a MM wasn't really helpful.

[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.

[dtmehall]

driver seat removal is the only way i found to get at the switch, unless you've got really tiny fingers!

[Jamie]

Issue resolved, not repaired. I pulled the instrument pod and removed the lead from the parking brake switch. Can easily live without the warning from parking brake release flashing. (IMG:style_emoticons/default/beer.gif) Thanks for the suggestions y'all! (IMG:style_emoticons/default/beerchug.gif)

[Spoke]

Can easily live without the warning from parking brake release flashing.

I did the same thing when the e-brake warning switch was not working. I fixed the switch after driving around for a while with the brake slightly on. Didn't notice it until I started smelling burning pad material.

[Jamie]

Can easily live without the warning from parking brake release flashing.

I did the same thing when the e-brake warning switch was not working. I fixed the switch after driving around for a while with the brake slightly on. Didn't notice it until I started smelling burning pad material.

I wasn't able to find details about the switch construction, and decided not to damage the original interior in my teener by tearing out carpet to explore further. Maybe after Okteenerfest I'll delve further into a switch repair when I have more time.

[Dave_Darling]

The circuit is pretty simple--the light flashes if either the switch on the master cylinder or the switch under the brake handle close and short the wire going to them to ground.

This also implies that any short to ground in either of those branches will result in the light blinking. Check for shorts.

--DD