Now that the warm weather is here, the A/C is acting up in my 1996 E320 with dual climate control (210 unit?). Cool air blows out of the passenger side Center vent, with hardly any air coming out of the passenger side vent. Only warm air blows out of the driver side vents, with good airflow from both the center and side vents.

Sometimes, only warm air blows out of both the driver and passenger vents.

Intermittently, there is an annoying squealing (or hissing) noise from the center vent. The noise gets louder as the fan speed increases.

A mechanic verified that the compressor is working, and he does not think that the Freon level is low (not sure how he checked). He wants to replace the climate controller.

After reading through the responses of several threads posted in the forum, I tried tapping the dual valve controller, under the hood near the passenger side firewall (no change) and the error codes from the climate controller are B-1232 and B-1234

Thank you for your time. Any suggestions and assistance are truly appreciated.

 

Hopefully he actually put the A/C gauges on to check the suction line pressure, If the refrigerant level is low on my 420 the drivers side blows warmer than the passenger side, due to saturation of the evaporator coil is insufficient. Is the squeaking intermittent? Or a slight squeal? just wondering if the low pressure switch is effecting the operation due to a low charge.

But then again you guys were able to pull up some codes to help the diagnosis.

 

Thanks, Rich.

The squeal is actually more like a high-pitched hissing noise, coming from the center vent. As I increased the fan speed, the hissing got louder.

By chance, do you know what the error codes mean? There are some other codes that were displayed in the controller:

1 - 35
2 - 32
3 - 32
4 - 26
5 - 31
6 - 70
7 - 12
8 - 48

B-1232 and B-1234

I'll ask how he measured the Freon level....

 

I'm Sorry but no I don't know the codes, but if you are hearing a hissing noise maybe a damper is stuck, did you look for any vacuum line leaks? If is like most autos the dampers are vacuum actuated diaphragms to open and close the dampers.

gotta tell ya, we both need to by the Haynes manuals