Blower doesn't work

Hi guys,
When I want to turn on my heater I don't hear the blower anymore. Yesterday I played a little with the switch and when I turned it on "off" and then on the "vent" the blower worked again. But this morning, nothing at all.
I have a '91 Chevy Caprice. What is the cause of this problem? And what can I check, or should I do first?

Check the resistor pack. That is usually the problem. It has a number of coils of different resistance to reduce the voltage that runs the motor. The only other part it can be is the blower itself. Aftermarket units have short fans and do not blow as much air, because some of the air leaks past the top of the fan, and back into the low pressure side. They are about 3/8 of an inch shorter. You can not rebuild the original fan motor, so the only option, if the fan is worn out, is to replace it. You can test the fan motor by connecting a battery across the leads...be careful, it starts with a lot of force, and can jump out of your hand if you do not have a good grip on it.

The resistor packs are cheap, and can be bought at Rock auto. The resistor pack is located next to the fan, and has 3 screws with 7mm heads. You must remove the knee panel on the passenger's side to access it. To get the fan out, you must remove the sill plate, at least the front part (do not crack it at the seat belt bolt cover), and remove the kick panel. The fan screws are the same type as the resistor pack. The wiring under there will try to interfere with removal of the fan, but you can disconnect the computer, and the rest will pull out of the way.

If I were going to replace the resistor pack, I would put silicone sealer on the bottom 1/2 inch of the leads to the coils. Water gets on them, and being dissimilar metals, they corrode.

Thanks Fred for your help. I took the blower motor out and tested it on the battery but there was no respons. So, I thought the motor is dead. But when I peeled off the outher housing I saw there was a lot of crap and leaves between the housing and the blower motor itself. When I cleaned all the stuff and tested the motor again, it was running like new. I sprayed some wd40 on the axle and put the motor back in the car and now the heater is working like new! So many thanks for your response and tips.

Glad to hear the fix was cheap.

Well, it was short cheap fix.....
The motor worked fine on the bench and also in the car. But after two short trips the motor stopped working again. So, what's the problem? Should I buy a new motor? Or check something else?

Check the motor again. Depending on the miles on the car, and the hours of usage, I wonder if it is the coil pack, or a connection. The motors can last for 200K miles.
If it does not work, you must buy another one. And as I stated, the aftermarket units are not as tall as the OEM units. I have a few tested OEM used units for sale.

I've checked the wiring, but there's a current when I put the heater on. So, I've ordered a new motor at Rockauto because it's obvious that the motor is not good anymore.
The current values are as follows: on 'low' I measure 0,04V. One level harder I get: 11,6V. One more level higher I get: 11,8V and at the 'high' level I get 11,9V.
Are these good? Or is the resistor pack also broken?

The motor you ordered from RA is going to have a shorter motor/fan height, and you can not move your other fan to it. This will mean less air flow. There is little you can do to make it work better. Check this thread on ISSF: http://www.impalassforum.com/vBulletin/53-heating-cooling-hvac/1300938-hvac-motor-upgrade-replacement-w-newer.html#post11978890

The voltages may or may not be proper, I have never checked them. The resistor pack is fairly cheap, and replacing it is not a bad idea.

I've replaced the motor and it works fine now. I've ordered one at Rockauto.com. I believe it's a VDO motor and the blades are indeed a bit shorter.
But I don't feel much difference now since my heatermotor exit was full with a lot of crap and leaves. Maybe, I have even more airflow now.