Heater blower/ windshield wiper help, please

[darthpanzer]

Hi, folks. First post here.

I have a problem with both my heater blower and wipers on my 1991 Ciera 3.3. Noticed it a couple of weeks ago when my heater was cutting off and on while driving. A few days later, it was raining and the wipers starting cutting off and on at the same time the heater blower was. So, either both work or neither work. I've checked them both, so have several other people, and we're all stumped. Fuses are fine, as is all the visible wiring and connectors (thought it was the hot connector going to the blower, but it wasn't). I'm figuring perhaps the wires are crossed somewhere, or perhaps a fusible link we haven't found yet, or perhaps a problem with a relay. Any ideas ? I would truly appreciate the help.