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norustscott
It started about a year ago with with the relay clicking occationally, but the big red warning light not blinking. Then, constant relay clicking and yesterday the light starts flashing with teh relay. I have disconnected the leads to the master cylinder switch and verified that the parking brake switch is in the off, no contact, position with no change. (BTW, there does not appear to be a reset button on my switch...)

Does the master cylinder switch complete the circuit or break the cicuit?

I also disconnected the third wire, the one with the diode inline, from the back of the waring light bulb socket. Still, the relay is some how getting a feed with 12 volts and sending the pulse to the guage light...

Any thoughts?

Thanks, Scott
double-a
have you recently bled your brakes? the usual cause for this is the loss of pressure in the brake system, making it necessary to reset the switch on the side of the mc. the switch is located under the boot where the wires are. it's a pain to reset sometimes, though i have found a way to to reset it without having to jack the car up or take the wheel off.

but i don't know... your issue almost sounds elecrical.

~a
ptravnic
Track down your emergency brake wire going into the handle. My ground would disconnect/connect and the dam "big red light" would flash - caused me a few season's worth of frustration...
Jonas
Can you enlighten me about your way to reset it without having to jack the car up?
I just had a local mechanic replace the reservoir boots and rebleed the brakes. I got the car back and the stupid light was flashing. I will probably bring it right back to him and ask him to lift it and all that, but my biggest problem is that I do not have a good way of lifting the car high enough to get my head under it.
Ramps ruined my front air spoiler, and I can't get the trolly jack to get it very high.


QUOTE(double-a @ Apr 27 2006, 09:14 AM) *

have you recently bled your brakes? the usual cause for this is the loss of pressure in the brake system, making it necessary to reset the switch on the side of the mc. the switch is located under the boot where the wires are. it's a pain to reset sometimes, though i have found a way to to reset it without having to jack the car up or take the wheel off.

but i don't know... your issue almost sounds elecrical.

~a

McMark
Not all brake master cylinders have the reset switch.

idea.gif I wonder how many times I've said that over the years? lol2.gif
BigDBass
Yeah, my '74 doesn't have one. Clayton reset my blinking red light somehow after we found that out. Not sure how. I liked the light cuz it seemed to tell me that my handbrake was on. Now it doesn't. confused24.gif
Dave_Darling
If your MC does have the switch, you can turn the steering wheel all the way to the right. The reach into the fender well, aft of the wheel, into the area where the steering rack and the master cylinder live. You should be able to see where the wires plug into the MC; that's the switch. Feel for a rubber nipple on the switch, and if there is one press it inward. That's the reset button for the switch.

The switch grounds the single wire going to it, or connects the two wires that plug into it together--and one of those two wires is a ground. (Some switches ground through their threads, while others have a separate ground wire.) Unplug the brown/white wire from the switch and see if the light goes off. If not, then the MC switch is not contributing to your problem.

If that is the case, check the button under the handbrake handle. Try pressing it down manually. If that turns the light off, then your handle is not pressing the button correctly. If it does not, then check the wires going to the button. If the brown/white one has fallen off and is touching a ground, the light will switch.

Similarly, if the brown/white wires anywhere in the circuit wind up getting grounded, the light will flash.

...The wires could be brown/yellow instead of brown/white, but I'm sure they're brown with a lighter-colored tracer stripe.

--DD
Toast
Dumb thought I know, but........you might want to make sure that the shop topped off the break fluid. If the fluid in the resivor (sp?) is low or out, it will trigger the switch.

And check the resivor (why the heck can't I find the spelling of this on mw?!) before you go on long trips to the middle of nowhere.
Ask me how I know. slap.gif tongue.gif
SirAndy
QUOTE(norustscott @ Apr 27 2006, 10:03 AM) *

and verified that the parking brake switch is in the off, no contact, position with no change.


easy way to test, take the brown wire off the parking brake switch, then find some ground and hold it against the ground.

see if that makes any difference in the blinking, both with the wire on ground and off ground.

i have seen this a few times when the brake handle doesn't fully depress the switch or the switch is broken ...
smile.gif Andy
swl
FWIW. Way back in the day I jerry rigged a new wire to the switch because of similar flashing. When I tore out the interior for restoration I found the original wire and been pinched to the point of breaking. Looks like it might have gotten caught in the seat adjuster.
904svo
If your mater cylinder don't have a reset switch, disconnect the wires, unscrew the warning switch out of the master cylinder this will reset it, then screw it back in and reconnect the wires.
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