My heater works. . .sometimes. When it doesn't, which is usually anytime the outside temp is below 42 degrees, it won't blow at all. It did this same thing last winter, but would come on if a hit a bump in the road, but now that doesn't even seem to make it come "on". Im not absolutely certain, but my AC isn't holding freeon and it may be leaking from the compressor itself. I toughed the summer out because I know if the AC compressor does need replaced, it would be quite costly. What might give with the heater intermittantly working?
Heater with a mind of its own! on 1997 Pontiac Bonneville
This can be a problem with just about any part of the blower motor and/or control system. It will require a diagnosis of the electrical circuit that supplies voltage to the blower motor and the blower motor itself. If it isn't working, then that make the diagnosis much easier than than an intermittent problem.
I had the same issue last winter on my '97 Bonneville. My heater would blow air then it wouldn't. I would sometimes hit the dash or a bump and it would work. I finally changed the heater blower motor in Dec., 09 and it has worked fine ever since. Motor cost $45.00. Check around for one.