I have a 96 e300d and started car today and heard a squeal and then it stopped. Driving and noticed no ac. Looked user hood and clutch was not engaging. Read and cleared the codes and now clutch engages, but still blowing hot. Have 2 codes that won't go away:422,459. Both deal with the instrument cluster from what I've read but I need to know what to do and what's wrong. Please help its 100+* here in Florida.

More info. Have you ever had the system re-charged? Is the compressor, drier, etc, original?

Also, you might ask the moderator to move your post to Diesel Discussion as there are more diesel nuts......er enthusiasts.....that might see you're post......granted its a general a/c question.

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'89 260e (212K Mi.), '92 400e (208K Mi.), '92 400e (not a misprint) (146K Mi.), '95 C220, '81 240D--Sold

Never had to have it charged it's been perfect till today! I'm assuming all original

What are the sensors numbers?

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CENSORED due to not family friendly words

In the meantime, you could do as we do. (Our 98 W210 evaporator is kaput). Drive with sunroof open

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

I just went through this with my 1991 300SL, but it's true for all a/c units for cars. When the car is running, you turn on the a/c, you hear a short squeal, then the car stops running, what has happened is that your a/c clutch engages, but since the compressor is seized (will not move due to some internal breakdown), it causes resistance to the motion of the engine, it is detected and the engine controller shuts down the engine.

With the engine off, reach down with your hand and see if you can turn the only the clutch part clockwise or even at all. I think you will find that, as I did, you will not be able to turn the clutch. If you are able to move it with only moderate resistance, then you are lucky. The squeal is a typical sign that your compressor is locked up and is in need of replacement.

Otherwise, if it can be rotated, unplug the two leads to the pressure switch that are right on top of the dryer/accumulator (not at the side where there are two short wires that lead to a sensor). Start the car, take a paper clip and connect the two leads (jump the leads) and this should engage the clutch. If it doesn't, test to see if you get 12 volts at the leads when you jump the leads.

As I said, I'm going through this right not with my SL. When a compressor seizes, it's likely that metal sludge is now in the system and needs to be removed or the cooling won't be very good and your new compressor will have a very short lifespan.

I'm ordering a new compressor, accumulator/dryer, condenser (because it's almost impossible to adequately clean out the very thin passages in the condenser), expansion valve, and will use a/c system cleaner (in a refillable pressurized can and hose- FREE from Autozone Rental Tools) to thoroughly clean several times the entire a/c system (hoses and the evaporator) before installing, drawing a vacuum over a couple of hours and re-filling the system with, in my case, the original R-12 that it was designed for. It had been converted to R-134, but I'm converting it back so that I get the maximum cooling efficiency it had before. Yes it does sound like a lot of work, but it will fit in one full day or over a weekend.

Good luck and let us know what you found.

AL

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03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio

Ok my car didn't shut off after the squealing stopped it ran just fine. And I've already checked the clutch by turning it with my hand and it spins free. Clutch engaged every time now with av on but will not blow cold at all.

Lucky you. If the clutch is pumping then there's enough pressure in the lines for it to cycle. Check to make sure your heater mono-valve is working by setting heat temp to max and getting hot heat (if it's hot outside try first thing in the am). If it's stuck on, then hot coolant is getting to your heater core and cancelling your a/c. Next, get some a/c gauges ($40 at harborfreight.com) and see what pressures you are getting in the high and low side. I also had another 300E that had a turning clutch but the compressor wasn't showing any high side pressure (internal compressor failure). I'm not trying to further support my idea of a bad compressor, but these a/c systems are fairly straight forward. It's either the clutch isn't getting any power (not the case for you) or something is cancelling your cold air (unintended heat in the vents, blockage in the system, or not enough pressure to push the refrigerant around in the system). Good Luck.

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03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio

And the self diagnostic sensor outputs are... ?

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CENSORED due to not family friendly words

What I've done on my last 2 Mercedes is to have the compressor pulled and an ounce or so of compressor oil installed. They used to have a dip stick where one could see the oil level, but no more. I've never had a compressor go down again.
Anziani
'97 CL600 50K

How do I get these tj?