Heater quit working.

[The Dude Abides]

Where should i start. Im not getting anything, power to any function. Nothing in the blower motor is responding. And the blower motor is fairly recent.

[nipper]

Check to see if there is power getting to the switch. I think this has a blower relay, I am not sure.

[The Dude Abides]

which switch.

[nipper]

The switch that turns the fan on

[nwtech]

i had the misfortune of having the same thing happen 2 weeks ago in my 91 loyale, and it was -10 outside, couldnt see a thing, windshield was icing up, took off the inst cluster trim and found a wire grounding itself when jiggled from the switch going into a circuit board, need to replace it, still have it loose if i need to jiggle it while driving lol, check behind there and start wiggling wires goin to the blower switch

[Tycho]

I had a fun game chasing heater problems on a car I just got on the road.

 

It had a missing thermostat

A plugged heater core

A dead fan relay

A burnt fan switch (which had gotten hot enough that wires unsoldered themselves)

and a dead fan motor.

 

So "nothing" worked ... but "everything" made it finally work.

 

I'd start by replacing the fan relay and doing the old +12v test on the blower motor. Aftermarket blower motors often have sticky brushes. You can fix this by taking the motor apart and using fine grit sandpaper on the brushes.

 

Then check the fan switch. If it's arced enough for the contacts to burn, the wires can actually come unsoldered from it externally too. They are fairly easy to rebuild with some sandpaper, a flat surface, and some patience (to refresh the internal contacts ... sand the pits out and the carbon off).