The high speed on my blower fan just quit working abruptly. Can it be the relay, the resistor of the switch? Everyone I talk to says that the relay should just be good or bad, no in between. Can someone help with the diagnosis??

Do you have Auto Climate Control, or the standard system? If you have the standard system, you have two relays for the blower control. One for high speed, and one for varible speed through the resistor module.

I have manual control. Is that why there are two relays (4 pin and 5 pin) listed in some sources?

It looks like both are five pin according to my parts source. I don't recall but you may have a seperate fuse for the high side. Pull the relay from the high side and check for 12V to the connector. Of course, the ignition switch and fan (high speed), need to be on.

Location:
http://autorepair.about.com/library/illustrations/bl457lib.htm
1993 Buick High Speed Blower Relay (Same as 95)

Relay part numbers:

ACDELCO Part # 155672
RELAY,BLO MOT CODE 5090 {#12135090}

ACDELCO Part # 158719
RELAY,BLO MOT w/A/C FRT ELEC CONT(C67); OFF BLOWER-STAMPED 3601 {5 PIN, MINI, BLACK #12193601}

STANDARD MOTOR PRODUCTS Part # RY282
5 Pin {RELAY - HVAC BLOWER}

The relay worked like a charm. I have lots of cold air inside the cabin now. Thank you much HotZ28!!!!!!!!!!!!

I love it when a simple problem is resolved!!!!