The heater will not work then ill be driving and it will suddenly come on , Sometimes it may not come on in any position lost and freezing in chicago !!!

Kasper

I'm not sure what year car we are talking about, but sounds like it could be a short in the blower motor. It can happen to any motor of any age, but the older one gets, the more likely for it to happen. If it's an older unit, the cold could be affecting it, and then when the engine compartment warms up after driving for awhile, the motor becomes warm and operational again. Has the blower motor made any noises when it was on in the past few weeks?You could also check the electrical connection to make sure it is on all the way, and clean.

Its a 1999 no noises at all i will check connections though

Its a 1999 no noises at all i will check connections though

Try wiggling your ignition while the car is running...I had the same problem with a 1991 Suzuki Sidekick and it was a short in the ignition. When I moved the key to shut it off, the heater would come on. Took me a few tries before I clued in [duh...]

Hope this helps,
OldGuyCar