The blower motor on my 97 C3500 (crew cab,5.7L with 126k miles)has been doing wierd things. Wife tells me it's been going on for a couple of weeks, so I drove it this morning. For no apparent reason, it will just quit blowing air totally. Switching the fan speed switch makes no difference...it won't come back on no matter what I push or test to try to coax it back on. Moments later, again for no apparent reason, it'll come back. It went off and came on 3 times during my 5 mile trip to work this a.m. Dropped it off at my mechanic, he took it for a ride and couldn't get it to act up. It switched off and on 1 time on my way home for lunch, and I was going 40 mph on a nice/non-bumpy road. This morning at a stop light during one of it's episodes, I did notice that the a/c compressor was still engaged even though the fan quit blowing, and turning compressor on or off had no affect on the fan. It seems like it would be a short somewhere, but I tried going over bumps, hard braking, and hard acceleration to try to jimmy the short and nothing seemed to make a difference.
I did a few searches of this group, and found a few similar posts recommnding checking the blower motor resistor, but those folks had lost a fan speed or 2..didn't sound like my problem. Where is the fan motor on this vehicle? Do you have to remove much of the dash to replace the motor if there is a short in the motor? Other posts suggested the blower resistor was acceessed thru the glove box. Any help is appreciated. TIA!