I have a 2001 S430 that has and a/c problem, the problem is the a/c works some time then it only blows hot air other times. I've taken it to two dealers and the both tell me that when they check it with the computer they get no fault codes. When I turn on the air some times it takes about 3 min before the air starts to blow one dealer told me that I would need to replace the following items, exp value, compressor, air dryer, and o-rings I think the guys is just guessing myself does any one out there now what the problem might be.

Cleve

 

From similar experience this is what I would do:

Either try an independent MB repair shop or an A/C repair shop and =
-have a complete A/C system and Freon condition checkout.
-take the risk anyway if too many unknowns and have A/C system checked for leaks, and then have the A/C system vacuum evacuated and fully recharged. Unless a specific part is found to be completelydead/inoperable, high probability the A/C will restart working again. Cost is acceptable and the Freon recharge will not hurt our atmosphere.
-if leaks reoccur or another item is found bad, it was well worth the minor $$ experiment.

Let us know what happens.

 

They checked for leaks and there were none and the freon was full no lines were blocked but they still can't fine the problem. If the switches for the climete control were bad would they cause thesetype of problems when I press the on switch some times it comes on right away and some times it takes a few min before it starts to blow air and the air is warm not cold like normal. Witch part signals the compressor to come on

 

Cleve,
Your first post had a statement that I found a bit confusing.. You said that when you took your car to two dealers..."both tell me that when they check it with the computer they get no fault codes.

It's my understanding after reading the series of posts at the link below, that the Climate Control Unit Diagnostics and Fault Codes are accessed at the unit itself. This string of posts explains how to check these yourself, but no external computer has to be connected to do this. All values are presented in the screen on the CC unit.

Good Luckand hope this helps you diagnose what may be happening with yours.

http://www.benzworld.org/forums/r129...ml#post2465534

Bob

 

SunGuy62

That's correct they get no failure codes, I've had the car to the dealer here in Fayetteville NC for over two weeks and the can not fine the problem.At first when I would take it to them it seam to start working so the dealer told me to bring it back when it stoped blowing cold air I did and they hooked it up to the tester and could not get a code the told me the replaced the rear SAM and it started blowing fine again it only lasted for a few days and it started blowing warm air again it is currently blowing warm air and had not blown cold air for the past 5 days.

 

sounds more like your HOT AND COLD valve is plain up its on the bottom of skatel panel which is under the wiper motor mechanism,its like two out lets of the pipe and wire connector very very common on the s class and cl class replaced no end of them .........................

 

Thanks NAZ

I'll have the Mech check this out.