Intermittant AC and other climate functions

[ds190]

My 1995 E300 Diesel, new aspirator blower Apr 08, system charged with r134 May 08.

The A/C system cools fine (but the fan never slows down) and all buttons/all functions work also. But if temp wheel is adjusted away from Min or if the engine is turned off and then soon restarted, all functions/all blower speeds stop or remain off.

I pulled pulse code 30 (circulator motor short circuit), and unplugged it. No error codes. However, I still have the intermittent function of AC as described above.

I noticed that if I turn the ignition on but not start the car, all functions/all blower speeds work, but if I immediately turn the engine on, AC stops and no functions/no blower speeds. But NO error codes!

Any thoughts about what I should do next?

Thanks, Dave

[lafooy]

might be a climate control push button issue or a blower motor regulator issue .... see if this helps especially post # 10 and on .... 94 e320 a/c issue please help

I would start by ensuring that the sample blower is working. Cut a piece of light paper 1CM square and hold it against the grille near the rear view mirror. If the sample blower is working it will hold the paper square in place with the ignition switch on.

[ds190]

Thanks for the input.

Sampler blower = aspirator blower. After I bought the car in Mar 08 and noticed AC issues, the first thing I did was the paper test. Paper did not stick, so new aspirator blower. Then r134 was charged in May. ACC seemed to work for a while, but problem returned.

I recently swapped a CCU (PBU) known to be working out of my father's 95 E300, and put mine in his. No problems with my former CCU/PBU in his car, and I thought no problems with his former CCU/PBU in my car. That did not last

I will admit that I did not know one could pull codes related to the ACC system until this morning. So got code 30, disconnected the circulator motor, and got no codes with either the ignition only on or with the engine on.

I hope the shorted circulator motor has not damaged the CCU/PBU

It's perplexing, and even more so as the ACC in my 300TE and 320CE have always worked perfectly.

I am open to all ideas. Thanks, Dave