Questions and Answers

Chevy S10 Heater Modes Q. I have a quick question about the Heater Selector switch in my car. When I turn the switch to blend mode (Windshield/Floor) it works like it should When I turn the switch to defrost mode (Windshield only) it works like it should When I turn the switch to foot mode it works as if it was in blend mode.

I know that this heater-A/C system works on a vacuum system, but I don't know where to start looking. I'd rather not tear the dash apart if where I'm suppose to be looking is under the hood. Could you please advise on some areas that I could start that might be possible cause to the problem.

1999 Chevy S10 4X4
V-6 Automatic
50,000 miles
ABS
A/C
Cruise

Thanks,
BG

A. It sounds like there is enough vacuum but to be sure check the vacuum storage ball under the hood. It should be bolted to drivers side of the hood itself. Make sure the hose is on, make sure there is vacuum to it and it has no leaks. trace that hose to be sure it's not melted or cut along the way. Sounds like a bad door diaphragm in the dash to me.