Proportioning Valve Keeps Tripping? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**MikeB** · 03-14-2024, 01:42 PM

My almost-new switch all of a sudden got very sensitive, even when not applying the brakes. I pulled it out and checked it on the bench with an ohmmeter. Turns out that just a very small bit of upward movement causes the switch to close. I mean we're talking .050" if that much.

Ended up using the later model switch that came with my aftermarket combo valve. Unfortunately, the wire connector is different, but that's no big deal -- just another PITA to deal with.

This is probably not your problem, since your switch closes only when you step on the brakes. But I just wanted to get this info out there -- the light flickering or being on all the time could indicate a bad ChiCom switch.

On another note, that's a dual 8" booster, right?

03-14-2024, 01:42 PM	#7
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 4,036	Re: Proportioning Valve Keeps Tripping? My almost-new switch all of a sudden got very sensitive, even when not applying the brakes. I pulled it out and checked it on the bench with an ohmmeter. Turns out that just a very small bit of upward movement causes the switch to close. I mean we're talking .050" if that much. Ended up using the later model switch that came with my aftermarket combo valve. Unfortunately, the wire connector is different, but that's no big deal -- just another PITA to deal with. This is probably not your problem, since your switch closes only when you step on the brakes. But I just wanted to get this info out there -- the light flickering or being on all the time could indicate a bad ChiCom switch. On another note, that's a dual 8" booster, right? __________________ Mike 1969 Custom/10 LWB -- owned for 37 years. 350/TH350, 3.08 posi, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. Hedman stainless headers. Old Air installation in progress. 1982 Custom Deluxe 10 SWB -- converted from 250-six to roller cam 350 w/ Vortec heads -- sold 1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it! 1969 C10 (not the current one) which I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 26 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.