Fried board in climate control????
 

Pulled the climate control head out and opened it up and am seeing what looks like burn marks on the back by the hole that is in it and the plastic is partially melted. Also, the circuit board looks like there are a couple of pins that may have fried. I am attaching a photo(I hope it isn't too large) not sure if you can tell anthing but this is directly in line with the off push button at the back of the circuit board.

Can anyone confirm whether or not this would cause intermittent operation of the climate control and can you get these board seperately or do I just need to replace the whole thing??

This damage could have been caused by something else in the car. If that is the case then a new module will suffer the same fate. I read somewhere on this board that the auxiliary water pump can cause damage to the climate control module if it shorts out and goes to a high current state. Not sure how to check this. Do a search for auxiliary water pump and you should find some help. Again, do everything you can to determine what caused this before putting money into new parts.

Dan

Hell, I have the factory service manuals and it doesn't say a word about how to check the aux water pump.

All I can suggest is to search this board for any thread topics containing "climate control" or "aux* AND water". I know I read threads about this before so you should find something. If no one else chimes in on this you could repost and ask for help on testing the aux water pump (with a fried control module) to determine if that is the problem. I,ve found that there is a wealth of information here if you dig deep enough. Good luck.

Dan

You might want to resolder all the connections on the board first.

I unplugged the aux water pump and low and behold I now have AC throughout the rpm range.

Not going to worry about the board on the climate control board for now.

Well I was going to suggest just disconnecting the pump for the summer and I guess you already have.

The test of the pump would be to jump it from the battery with a fused jumper and an inductive ammeter on the wire. It should probably have less than 1000ma draw.

You are right that the MB service manual doesn't discuss this. The main reason for that is that this kind of testing is basic auto repair 101. Service manuals do not teach auto repair and electrical theory. Those of us who use them as intended would revolt over the wasted text. Service manuals are designed for use by experienced technicians, who don't have time for reading a bunch of basics. In the case of this issue MB should give an amp spec for the motor and they don't. They do not need to tell a technician how to test it.

My spec of 1000ma, 1 amp, is a guess it could be 2 or 3 amps. It would be nice to have that info.