Some times the connector, on the back of the blower switch, or on the resistor corrodes and burns, the circuit is on the high side using a 30 amp fuse, a lot of current. The resistor is how it gets the different speeds. However, in high speed, the switch bypasses the blower motor resistor, the next part to check after the switch. However, if it cuts out in high speed also, it is not that, but they fail quite often. Find the resistor is not always fun. Try under the hood, or behind the glove box. It is usually under the hood on the right side on the upper firewall or in under the cowl. In 87 I know it was inside, on the right, the harness runs on top of the whole heater box, a small wiring plug goes to the motor and it continues to the resistor. It has a bigger 5 wire plug and looks like springs on a 2 inch by 4 incg block.
Tuesday, October 6th, 2009 AT 8:47 PM