nomorerotors

Whenever I press the A/C button on my 89 951, the recirculation flaps close so that the inside air recirculates. This happens regardless of whether I have the recirculation button pressed or not. If the recirculation button is not pressed and the A/C button is not, then the flaps open for fresh air. Is it normal for recirculation to be forced when the A/C button is pressed? Could the temperature sensor being affecting this? Any ideas how to fix it?

Thanks,
Mark

hosrom_951

There are two solonoid vacuum valves beside the glove box, one controls the flaps and one controls the heater. You need to remove the glove box to access them and to check the vacuum lines, and you also need to check the vacuum lines going into the engine bay.

Those vacuum lines going into the engine bay, also go from the top of the blower assembly. You will find two vacuum actuators on either side of the blower for the flaps, make sure the lines are correctly routed and you should be fine.

nomorerotors

Thanks for the response. All vacuum lines and solenoids are fully operational. Maybe I didn't explain it well. I have verified the operation of the solenoids by the fact that when the AC button is not pressed, the recirculation button does control the flaps as I would expect. Push the recirculation button and the flaps block outside air. Press it again and the flaps allow outside air.

Other verification that I did included disconnecting the vacuum line providing vacuum and reaching the solenoid controlling the flaps and applied vacuum to the solenoid via mighty vac. Next I verified the recirculation button controls the flaps as I expected except when the AC button is pressed. So I'm confident in all vacuum lines working, the ability of the control unit to send the electrical signal to the solenoid, and the solenoid to actuate properaly based on the voltage being applied or not applied.

This must either be the normal operation or there is something wrong with the AC control unit. I'm looking for someone to see if their car operates the same way or I need to replace the AC control unit.

hosrom_951

Yeah, it sounds like the ac control unit may have something up with it. If you know a friend with the same car as you're, you can swap units and verify if the control unit is the problem.