Ormist

Could a vacume leak be the case of my heat not working?

97FordGT

i am not sure if it could cause the heat to not work. i havent heard of that b4 but can u hear air sucking from somewhere or is your idle off.

vfast

only if it's in the heater contol area..

hotrodman

that model dont have a heater valve with vac..could be your cable for our flaps

mmoto68

I have a '95 GTS. The heater control switch runs off of engine vacuum.

The main vacuum supply runs off of the firewall. You can trace it from the Brake Booster. The supply goes from the engine to a junction on the driver's side firewall, one goes to the brake booster, the other goes to the heater control. Since it's a cheap vacuum line subject to engine heat, it's probably cracked. If you pull off your glove box door, you can see the other end of the hose at the vacuum switch for the heater.

You can also test the switch by getting a good vacuum source and plugging it into the switch.