Heat And A/c
 

HEY GUYS, I HAVE A 1989 560 SEL AND BOUGHT A HEAT MODULATOR VALVE FROM YOU THE OTHER DAY, INSTALLATION WAS STRAIGHTFORWARD AND EASY ENOUGH. THE GOOD NEWS IS I NOW HAVE PLENTY OF HEAT! THE BAD NEWS IS THE A/C HAS QUIT. WHEN THE CLIMATE CONTROL RING IS TURNED TO THE COOLING SIDE THE COMPRESSOR TURNS ON AND YOU CAN HEAR THE R-12 PUMPING THROUGH THE EXPANSION VALVE, BUT THE AIR IS NOT COLD. IS THERE A CONNECTION BETWEEN THE VALVE I REPLACED AND THE A/C SIDE? ANY SUGGESTIONS WOULD BE APPRECIATED!

Most likely it is the vacuum acuators that operate the air flappers. They tend to rot and need to be replaced. You should check each of them to be sure they hold vacuum. You will need a hand held vacuum pump/tester. The whole vacuum system for directing air needs to completely checked as well as the 7 way vacuum valve assembly which switches the vacuum to the flappers. Sometimes the valve gets plugged up. Take it out of the car and bench test each circuit for proper operation.