1994 S-10 blower motor has a funny habit of running only sometimes. It's always running smoothly on low with no noise. About 50% of the time all the speeds work fine. The other 50% the blower stay on low, no matter what position the switch is in. Motor appears good and I replaced the resistors with no change. It's cold and I can use a little help narrowing down my problem. Can you help me, please?

It has to be a loose wire, or the switch it's self

1994 S-10 blower motor has a funny habit of running only sometimes. It's always running smoothly on low with no noise. About 50% of the time all the speeds work fine. The other 50% the blower stay on low, no matter what position the switch is in. Motor appears good and I replaced the resistors with no change. It's cold and I can use a little help narrowing down my problem. Can you help me, please?
I have the same problem!!! If you find out what's wrong let me know. I will do the same! good luck!

1994 S-10 blower motor has a funny habit of running only sometimes. It's always running smoothly on low with no noise. About 50% of the time all the speeds work fine. The other 50% the blower stay on low, no matter what position the switch is in. Motor appears good and I replaced the resistors with no change. It's cold and I can use a little help narrowing down my problem. Can you help me, please?
I WOULD DEFINITELY TAKE A CLOSE LOOK AT THE SWITCH, AND THE WIRES THAT CONNECT IT. THE SAME THING HAPPENED ON MY DADS RANGER, AND IT TURNED OUT TO BE THE SWITCH HAD BLOWN, AND A WIRE HAD FRIED RIGHT AT THE SWITCH

Check that motor body has good ground wire connection.

Happen to me a few years ago. It was the switch. Replaced it. a week later the blower mooter went.