Where is the heater vacuum switch?

[guy48065]

So I'm outside in 5°F troubleshooting my under-performing heater. Tracing the lines per a vac diagram I have and I notice the valve in the coolant line is closed. Using a Mityvac & gauge I tested the vac signal that goes through the firewall to the control panel and I'm getting steady 22" with no leaks. The valve responds to the pump and also doesn't leak. There's just no signal to the valve.

My diagram shows a "vacuum switch" that routes vac to the valve--where is this thing?

 

[ROBinGa]

Just for discussion, cannot you physically unhook the vacuum to the heater control valve inline on the heater/coolant hose and move valve open for coolant to flow to heater core, until you can get your issue fixed?

 

[guy48065]

Sure --I zip-tied the valve open temporarily but now I want to fix it correctly.

 

[FordFool2]

Your vacuum switch is located just above the left big toe of your passenger.

 

[guy48065]

Your vacuum switch is located just above the left big toe of your passenger.

With the 5 vac hoses & an electrical connector?