2001 GMC Safari "heater vacuum" Questions

heater hoses back to the engine. Sometimes, a vacuum line could have a break causing there to be no vacuum to operate the valve. Also it should be noted that if this is your first winter with this car

...vacuum is reaching the heater control then the likely problem is that one of the vacuum operated servo "motors" that move the internal doors in the heater box has failed. If no vacuum is at the ...

...the throttle body.Usually gets brittle and brakes .This runs to the passenger side of the firewall this goes to the heater box.without vacuum the valve under the dash can not switch.I hope this ...

...vacuum supply to heater controls. have a 96 safari had same problem, has hard plastic tube running and laying all over the motor got hot and brittle kept breaking. tracked it down to other side of ...

vacuum switch broke inside heater air conditioner control switch, there is a little switch that two vacuum lines connect to, the connections are broke off and stuck on defrost all of the time does any

heater on - vacuum sucks to open valve. and before that make sure fuse is ok . for rear AC mine does not work either and it is leak on pipes that go from front to rear .. 10 feet of pipes and tubing $

...of the throttle body. these too break and will not allow the heater mode changes. the blower motor resistor controls the fan speeds and the vacuum line allows which vent the air flow goes

...airconditioner works as well the heater but will not blow out the front vents or anywhere else? Sounds like a vacuum leak. Check the vac supply on the intake manifold. Passenger side front of

...vacuum, the heater will go into the defrost mode. There should be a small line, about 1/8 inch in diameter, that goes from the engine to the firewall. It's most likely on the passenger side. i agree ...

Where are the vacuum hoses for the heater control for 1997 safari runs off intake on drivers side of thottle body to passanger side heater box . They get brittle and break by throttle body .