1990 Riviera Heater-A/C Problem

[RivieraProudPapa]

I have Riviera with Auto Climate Control. My resistor control module was not working. I replaced it and noticed that when fan was running-very little air flowed from heater, defroster and dash vents. But outside of the car I can hear the fan running like a jet engine. It was keeping the car warm so I was happy tho. After a week the resistor control module goes out again-- this time fan was stuck on high even after shutting car off. Replace module again thinking it could have been a bad module. It was guaranteed and it happens. After a week- same thing. Now I think buy new fan and module- maybe fan is drawing too many amps. Got them installed but am now convinced that a blend door or something is not opening and air flow is not keeping this resistor module cooled--since it has a heat sink and big ol transistor on it. I'm not running the fan or heater now until I can figure this out. Any help would be greatly appreciated. Also I'm looking into rebuilding these modules cause they are expensive to replace and they cannot be that complicated.

 

[jcc3inc]

Sir,

I have a 93 and the fan control consists of a transistorized voltage unit that sets the fan voltage according to the heater control. Mine was bad so I got a used unit that works fine. I believe that you could repair one of these and I considered doing so but the used one eliminated the need. I believe the door position is powered by vacuum and directed by your heating or cooling selection pushbuttons.

I do have a shop manual for my 93 and could provide diagrams if you need them.

JCC

 

[jcc3inc]

Sir,

Attached is the schematic of the AC Blower controls from a 93 Riv. The Power Module is mounted on top of the air duct under the hood, and mine was black, having a heat sink that is inside the plenum. Pin B of C2 brings in the pulse width modulated voltage to control the blower speed. Hope this helps.
JCC

Sir,

I have a 93 and the fan control consists of a transistorized voltage unit that sets the fan voltage according to the heater control. Mine was bad so I got a used unit that works fine. I believe that you could repair one of these and I considered doing so but the used one eliminated the need. I believe the door position is powered by vacuum and directed by your heating or cooling selection pushbuttons.

I do have a shop manual for my 93 and could provide diagrams if you need them.

JCC

 

[Amanda Hugenkiss]

An old post but chiming in for posterity.... Mine had so much grime and crap on the evaporator at first I thought it was a felt filter or something. You can view the evaporator by removing the blower control.module and peeking in the hole. If it's dirty get something in there to brush or vacuum it off. I also sprayed brake cleaner on it and that helped immensely. The difference in airflow was amazing. I may have removed the blower motor for more access. Been so many years I don't remember.

 

[DrivenDaily]

Here's a cleaner you can use that's made for the AC system.