Auto Air Conditioning & Heater Repair: 1993 Chevy Astro van, chevy astro van, chevy astro

Question
I replaced the air-conditioning blower and the fan speed switch (inside the van on the dash).  The reason I replaced these items was because, only the two high speeds were working on the control.  Also the fan started shutting off, if you wait a few minutes to turn it back on, it will work again for a while then shut off again.  It will not work continuosly.  Can you tell me what the problem might be?

Answer
I do not have a book on an astro van but here are some possibilities.

QUESTION: has ANY work been performed ion the vehicle for any reason prior to this problem whereas any electrical connections had to have been disconnected ?.

QUESTION: if the vehicle has a BLOWER FAN RESISTOR BLOCK usually monuted near the blower motor and is inserted into the blower housing assembly (plenum) check the FIRST largest electrical connection for internal corrosion of the wiring.

Your problem sounds much like that it is a corrosion and or loose electrical connection.