1974 Grand Am poor A/C

[74 Warlock]

My A/C has been switched over to the modern 134A and was working well. Now I barely get any air out of the vents.

1. The fan only has one speed which sounds like it is on High but low volume.
2. The fan switch works fine on the heat and vent settings.
3. I replaced the selector switch.
4. This problem is usually a resistor issue but I replaced the resister with a NOS #487892. I don't think there are any other interchangeable ones out there.

I am at a loss. Any one have an idea?

 

[melsg5]

are you working with a test light or voltmeter or just replacing parts? Do you have power going to and through the resistor? Have you checked the motor by applying full voltage to it?

 

[74 Warlock]

Ac

I am working with a voltmeter. I also just tried to replace the Blower Relay because the casing on mine looked bad. All the auto parts stores tell me I need a BWD R720. I bought one through O'Reilly Auto Parts but it has five blades and my car only has three. The plug fit but the blower came on without the key in the ignition. I believe I have tracked down the correct part number and will get a GM 481794. Hopefully that will solve my problem. Can't find much help out there and none of the shops in Colorado Springs want to work on such a rare, old car.

 

[melsg5]

NAPA has the correct 3 wire unit Echlin ECH AR107