Heater fan not working - 30 amp HVAC fuse blows out repeatedly when replaced. Where should I look for root cause? Have dash disassembled, but can't see any bare wires anywhere behind radio/climate controls/ashtray - what else could be causing the fuse to keep blowing out?

SOURCE: No parking lights, fuse keeps blowing.

There is a ground not connected or a wire open that is causing it to blow

SOURCE: heater fan blowing intermittently or not at all

Most likely it does, if you can hit the motor and it will run. I can't say for sure but you might want to chk. to see if you got a heater blower motor resister. There located (if its got one) around the heater motor and it controls blower speeds, might be worth checking out.

Mike Butler

• 6674 Answers
• Posted on Apr 01, 2009

SOURCE: 89 firebird blows fuse that powers fuel pump and ecm?

That joint & where wires separate, would be a good spot to use a clamp on amp meter, if you have, or know someone who has one, then you could get reading on each one, and zero in on one(s) with most draw.

SOURCE: heater fan blowing intermittently or not at all

unhook your battery unplug the harness that's touchy get a sharp object that you can pry the connectors together with you will see them wide open crimp then tight enough to get a good tight fit, the amperage draw from the motor has stretched them out and when it gets warn with current passing threw it opens up and loses contact. while it's apart take a emory board and clean the flat spades on the other side so you have a good connection.

SOURCE: 1997 Bonneville SSE, when the heater is turned on, only cold air

you may have a failed blend air door motor/actuator. this part will regulate the amount of air from the heater core depending on the temp setting on your electronic climate control unit. if it has failed, it will be stuck at the temp that it was last set at when it quit working. it is also possible the heater core may be plugged up, but using the gm recommended dexcool coolant and flushing it out every 5 years, it should not be plugged up. you can pull the 2 heater hoses off the heater core on the passenger side of the engine compartment firewall and see if the heater core is the problem. caution-do not use a high pressure air hose to blow through the heater core as this could damage it and cause a leak!