amg_sl55

Climate controller is not responding its just blowing straight air regardless of temperature setting, can't get Aircon or heating air. I changed out my climate controller read info from original unit and coded to replacement through star. Iv'e run all All tests I could find through star of AAC module and refrigerant system and everything pass, no faults, but still no heat or cooling just the ambient air temp coming through.

Everything on the controller appears to function AC pump comes on when selected, except no change in air temp either way.

At this point I'm baffled ... any suggestions at what to look at next?

amg_sl55

...still haven't solved this one and summer is here again ...any suggestions?

braddman

One side of mine is blowing cold air regardless of what the temp control is on. I am taking into MBenz dealer next week, because I have an extended warranty. I'll let you know what they find.

Risk7

There is a temperature sensor in the evaporator housing that may cause odd operations of the A/C system. This document has some information on it and I'm planning on doing this replacement myself when the next northern summer is here again.

amg_sl55

That would be great.. thanks

amg_sl55

going by that document that sensor stops the compressor cycling on, from what I see in star my compressor cycles on, I can see pressure increase from 2 bar static to over 6 bar but no cold air through vents..weird!

bobterry99

Those pressure readings are all wrong -- both are too low. With the compressor off you should see around 6 bar, and with it running perhaps 15. When the reading is 6 I suppose the command signal to the compressor is 70% and the evaporator sensor temperature is 20 or so.

amg_sl55

OK then I will try replacing the sensor next week and see if that changes things, fingers crossed.

bobterry99

I would assume the sensor is fine and would check the high and low side refrigerant pressures with a set of gauges.

amg_sl55

I don't have access to gauges so I'll probably have to take it in to a dealer, unless that's something I can check through star? One question though I also can't get any heat from the heater how would that be related to the refrigerator circuit?

bobterry99

It would be far cheaper to purchase a set of pressure gauges at an auto parts store than to pay a dealer. Also, any general repair facility can read the refrigerant pressures in your vehicle.

To check heating I would go into the Actuations menu of your Star Diagnosis. Make sure the heat exhanger shut-off motor is opening and closing. Also check that the left and right blend air flaps are functional. Those two components -- the shut-off motor and the blend air flaps -- are what is required to deliver heat to the cabin.

amg_sl55

I didn't think of that, your spot on with the gauges being cheaper than the dealer and I'll have my own set of gauges can't go wrong with that one.
I've always thought that my heating and cooling problems were relate
Thanks for the tips on chasing the heat problem, I'll have to take a look after Xmas, flat out with work and festivities over these next few days but at least now I have a direction to start troubleshooting.