Check the voltages on all the pins of the 3 pin connector under the hood (it is on the driver side, near the fuse box). The female plug easily comes off. One of the pins should have the battery voltage, another pin comes directly from the climate controller. This voltage varies and is the control voltage that goes to the blower regulator. I will have to double check my CD, but the voltage varies between some 2V to 6V or something. If I remmber correctly, the third pin is the ground pin. If you want details of the which pin is which, email me and I will look it up.
O.K., now here is what to do. Put the climate control settings so that the blower motor runs say on the fast speed (dont put it on auto). When your blower motor is working, note down the voltages on the two pins that are not ground. Do the same when the blower stops. If you see that the battery voltage has dropped, the problem is your ignition switch, replace it. If you see the control voltage drop, then the problem is in the climate control unit, before replacing it, open it and check if it is not just a cracked solder anywhere. If both the voltages are the same when it is working and not working, then the problem is with the blower regulator or the blower. For this, you will have to access the blower and the regulator. Once you have access, get the blower motor out and test it with a battery charger, let it run for an hour or so, if it runs fine, it is not the blower. Replace the blower regulator, very expensive part.
Saumil S. Patel