Pontiac Repair: Blower Fan, buick park avenue, automatic climate control

Question
1990 Buick Park Avenue 3800V-6 Climate Control Have taken blower fan out and hooked up to a 12v supply and runs at full speed replaced resistor module and blower fan relay on firewall. measured 12.4v at blower terminals. When switched to high measured 2.4 and also 2.4 when switched to low. When sitting in car I noticed the fan sounded as if it were kicking in as if it was not getting full voltage and would then stop all together after a few seconds. I've checked my fuses and have used name brand replacement parts any ideas any at all it gets cold here in the winter and I'd like to survive to see another summer! Which won't be the case if have to drive this ice box.

Answer
Hi Scott:
does this have automatic climate control "digital" controls or does it have manual controls with knobs/dials? when you checked the voltage at the blower motor did you check it across both terminals meanin you check the power and ground at the motor? or were you just checking the power going to the motor? You could have a poow ground to the motor and not a power issue. how about the connector at the blower motor do the termianls/connctor show any sign of overheating where it woul have a loose fit on the motor? how about the conntors at the resistor and the replay. a blower motor is a high amperage draw and any kind of a loose connection will cause the motor to not run or to run at a lower speed then intended.