Combination valve brake warning light - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Grf4413 · 11-26-2023, 08:27 PM

Just looking for part number for the brake warning light switch, on the combination valve. This is for the disc front drum rear. Looked at the jungle web site, evil bay and rockauto, couldn't find the style I have on my 71 GMC 2500.

**1970cstblazer** · 11-27-2023, 10:25 AM

This isn't it?

Grf4413 · 11-27-2023, 03:04 PM

Mine looks similar.. Just a little different on end that screws into combination valve. Mine is damaged on that end keeping contact closed. The one you have shown would probably work. Just ok don't know who carries this switch.

**PbFut** · 11-28-2023, 11:33 AM

I believed inline tube will sell just the switch. You will need to call them as I did not see the switch by itself on the web site but may have missed it.

RichardJ · 11-28-2023, 04:07 PM

This image may look a little messy, but it shows both type of switch. This isn't a combination valve, just the distribution block and switch, but shows the two separate flow paths indicated by the orange and yellow wires.

The threaded hex piece in the middle of the image slips over the nylon insulated pin next to it. The pin makes contact with the inside shoulders of the brass piston, when the unequal fluid pressure pushes it either left or right. The piston has O-rings, so the electrical path to ground is actually through the springs. The switch contacts are the pin and the piston.

In the lower part of the photo is the type of switch with a spring loaded pin. This is a conventional type switch that is grounded through the body of the switch. For this type switch, the brass piston will have tapered shoulders to help push the pin into the body of the switch.

Grf4413 · 11-28-2023, 10:51 PM

That's the style switch I have on the lower right. Got mine working again, a little dremel work got it moving again. Been working on my 71, haven't had the rear drums working forever. Nice to have all the brakes and the switch and valve all working. I'm sure someone sells the switch , be nice to have a part #.

**1970cstblazer** · 11-29-2023, 08:53 AM

As stated above, I think Inline Tube is the only one that carries them.

11-26-2023, 08:27 PM	#1
Grf4413 Registered User Join Date: Apr 2021 Location: Hume Posts: 6	Combination valve brake warning light Just looking for part number for the brake warning light switch, on the combination valve. This is for the disc front drum rear. Looked at the jungle web site, evil bay and rockauto, couldn't find the style I have on my 71 GMC 2500.

11-27-2023, 10:25 AM	#2
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 1,894	Re: Combination valve brake warning light This isn't it? Attached Images __________________ 1970 K/5 Blazer CST 4WD, TOTM winner December 2024! Medium Bronze, 93k ACT. miles, 350, 4 speed, rear positraction, 16.5" x 8.25" HD wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration finally getting close to completion.. 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... 2017 Sierra 1500 SLT 4WD, Black, 45k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 62k miles, 3.6, 8L45, 3.23 LS, 18" wheels

11-27-2023, 03:04 PM	#3
Grf4413 Registered User Join Date: Apr 2021 Location: Hume Posts: 6	Re: Combination valve brake warning light Mine looks similar.. Just a little different on end that screws into combination valve. Mine is damaged on that end keeping contact closed. The one you have shown would probably work. Just ok don't know who carries this switch.

11-28-2023, 11:33 AM	#4
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 643	Re: Combination valve brake warning light I believed inline tube will sell just the switch. You will need to call them as I did not see the switch by itself on the web site but may have missed it.

11-28-2023, 04:07 PM	#5
RichardJ Registered User Join Date: Apr 2010 Location: So Cal Posts: 1,470	Re: Combination valve brake warning light This image may look a little messy, but it shows both type of switch. This isn't a combination valve, just the distribution block and switch, but shows the two separate flow paths indicated by the orange and yellow wires. The threaded hex piece in the middle of the image slips over the nylon insulated pin next to it. The pin makes contact with the inside shoulders of the brass piston, when the unequal fluid pressure pushes it either left or right. The piston has O-rings, so the electrical path to ground is actually through the springs. The switch contacts are the pin and the piston. In the lower part of the photo is the type of switch with a spring loaded pin. This is a conventional type switch that is grounded through the body of the switch. For this type switch, the brass piston will have tapered shoulders to help push the pin into the body of the switch. Attached Images __________________ '67 GMC 2500, 292, 4spd, AC

11-28-2023, 10:51 PM	#6
Grf4413 Registered User Join Date: Apr 2021 Location: Hume Posts: 6	Re: Combination valve brake warning light That's the style switch I have on the lower right. Got mine working again, a little dremel work got it moving again. Been working on my 71, haven't had the rear drums working forever. Nice to have all the brakes and the switch and valve all working. I'm sure someone sells the switch , be nice to have a part #.

11-29-2023, 08:53 AM	#7
1970cstblazer All stock and staying that way Join Date: Jul 2003 Location: Elkland, PA Posts: 1,894	Re: Combination valve brake warning light As stated above, I think Inline Tube is the only one that carries them. __________________ 1970 K/5 Blazer CST 4WD, TOTM winner December 2024! Medium Bronze, 93k ACT. miles, 350, 4 speed, rear positraction, 16.5" x 8.25" HD wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration finally getting close to completion.. 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... 2017 Sierra 1500 SLT 4WD, Black, 45k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 62k miles, 3.6, 8L45, 3.23 LS, 18" wheels



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