Blower Motor Going Bad -- Or is there something else going on???

[mohawk]

I'm having some issues with my heater (blower)...which can be a real problem this time of year. Sometimes it works and other times it doesn't.

It started to occur a few weeks back. For example, I've noticed the following...

1. If the truck sits for a long peroid of time, like overnight (or serveral hours), the heater/blower fires right up and works like a champ.
2. If you turn off the truck, say to get gas, and then turn it back on again, the blower motor does not come on.
3. In the instance where the blower doesn't kick on, I've gently pounded on the blower box, and it fires right up.
4. All the fuses appear to be OK and the A/C compressor kick on, so it seems to be OK. I also played with the settings; hot, cold, fresh air, recirc, etc. and it seems to make no difference. The only way to get the blower working again is to let the truck sit for a while or to beat on the blower box.

Is it simply a bad fan motor or do you think there is more to it?

I've done a little research on this and found everything from bad alternators to bad resistor packs.

Just curious to hear what you guys have to say...

[mohawk]

FYI...this is a 2002 Isuzu Trooper. I'm just about ready to hit 100K. Besides a little oil usage, the truck has been great.

[fourwd1]

I'd lean towards the motor or a bad connection.

Does it happen at all fan speed settings?