Emergency brake warning light

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75gmck25

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My ‘75 GMC brake warning light comes on if there is a pressure imbalance in the brake proportioning valve (as designed), but there is no warning light to remind me if I leave the park brake on.

Was there a park brake warning light in any of the squarebody trucks? All years 73-87 seem to have the same replacement parts number for the park brake pedal mechanism, and I haven’t found any listing for a switch that fits there.

Bruce
 

eskimomann209

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There’s a thread on here that I piggy backed on once. It believe it was @AuroraGirl who Started the tread. It did indeed have a switch on the parking brake. Like the brake light switch. Once depressed it turned on the light on the dash. My truck doesn’t have one either and I blew through brand new drums having forgot about it.
I got home to see a smoke show. I drove 10 miles hard and fast and was none the wiser that they were engaged.
Since then I just double check before I take off LOL.
 

Goldie Driver

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My ‘75 GMC brake warning light comes on if there is a pressure imbalance in the brake proportioning valve (as designed), but there is no warning light to remind me if I leave the park brake on.

Was there a park brake warning light in any of the squarebody trucks? All years 73-87 seem to have the same replacement parts number for the park brake pedal mechanism, and I haven’t found any listing for a switch that fits there.

Bruce

Goldie (80) has one - as mentioned, I assume the switch is on the parking brake pedal.

What parts listing are you using ?
 

Goldie Driver

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It's hard to see or take a pic, but on the upper portion of the pic you can see a tan plastic piece behind the pedal and to the left of the flasher

I think that is it.

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75gmck25

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I’ve checked for parts on LMC and Rockauto, and neither lists a switch for the parking brake. I have also found a couple GM switches online, but it’s not clear what they fit or how they mount.

If your ‘80 has one, I’ll try to look at the repair manual and wiring diagrams for the ‘80 that they have on this site to see if I can find any details.

Bruce
 

AuroraGirl

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I do believe only later years had the ability because ... perhaps a tuck with a driveline brake maybe? I have no idea. I am gonna try and say I remember the guy who had a switch said you could install one in a bracket or maybe simoly add I'm guessing it came down to a vehicle where pressure imbalance isn't gonna be a reliable indicator perhaps
 

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Just hooks onto the back of the parking brake mechanism like said above. For sure 80's I think my 79 has one, may have been 78-79 those were years they changed quite a few things
 

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I rigged one up on my '76, Splice into the "tan/white wire" that runs to the Brake warning switch and connect it to a switch mechanism that is activated by the emergency brake mechanism. The switch should then connect the wire to ground when it is activated.
This is a Camaro one pictured here


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75gmck25

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I should be able to figure out how to add one similar to the one pictured above, but it would be interesting to see one of the original type. Since they didn’t change the pedal mechanism from about 73-84, I assume the OEM switch from 79+ (maybe when the they added the switch?) could be retrofitted to an older truck.
 

Blue Ox

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1985 microswitch near the firewall. The one with the brown wire with white trace.

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Goldie Driver

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1985 microswitch near the firewall. The one with the brown wire with white trace.

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That - from what little I can see it - looks like mine.
 

75gmck25

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Good pictures.

I’ve run across that switch in one of my searches. However it’s not the most common hit, so I will have to look through the sites that come up to find it again.

Thanks,

Bruce
 

78C10BigTen

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There’s a thread on here that I piggy backed on once. It believe it was @AuroraGirl who Started the tread. It did indeed have a switch on the parking brake. Like the brake light switch. Once depressed it turned on the light on the dash. My truck doesn’t have one either and I blew through brand new drums having forgot about it.
I got home to see a smoke show. I drove 10 miles hard and fast and was none the wiser that they were engaged.
Since then I just double check before I take off LOL.
I dont have such issues... ive NEVER used the E brake in any of my vehicles.
 

legopnuematic

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My 79 has a switch on the mechanism, my 76 does not, but the light will come on with the prop valve on the 76
 

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