My '93 190E 2.3 air conditioning has stopped cooling completely ? Is there, are there, any fuses / relays I should be checking out ? The engine is running fine but I can't tell if the compressor is even engaging ? I don't see any movement in the "looking glass" inline of the system either, guess the compressor could not be running ? Removed cap on AC line and pushed pin in and a relatively high pressure hiss comes out but NOT cold like I would expect ??? Any help would be greatly appreciated to see if there is something I can fix before having the air guys take me for a ride ! Thanks !

 

there is fuse and relay for it.

the magnetic clutch can be seen in front of compressor. does it engage when you turn it "on"? can you hear a "click"?

 

I had my wife turn the AC on and off while I watched the clutch and it DID engage each time she turned it on.....
I also reviewed the "spyglass" again and it looked like splashing water in it, not necessarily bubbles , but definitely some sort of liquid flow ?

 

There is normally a gas/flfuid sensor attached to the dryer near the spyglass.
This is used to cut off the compressor if the gas in the a/c system has fallen too low pressure due to leakgae or whatever. This is a safety measure to protect the compressor.
Check the gas in the a/c system.
If there is gas at normal level, check to see if the switch is faulty by shorting it.
Good luck.
Shan.

 

yes, it's in liquid state in high pressure side.

bubbles means the refrigirant (freon) is not enough. you need to fill it up just enough for the bubbles to dis-appear.

750 grams if empty.

 

Sounds great,..
1. I am aware there is the "old" freon and whatever the "new" type of freon is....
How do I tell which freon is in the system ? or should I just drain it and put in the
new type, which I believe is the only kind they will sell me over the counter ?
2. Where is the "cold" side valve to refill the system ? I don't want to get blown up !
Thanks for the help again,...

 

use freon 12. freon 134a was still not widely use for 1993 models.

the low side (cold side you mention) got the bigger service valve on it on 134a but the same size in 12.

the one near the filter/drier is high, and low side is the one coming outside from the firewall.

just use a little bit of imagination.

 

Hi, I have a good writeup of the 190 ACC system which might help; how can I send it to you? I got it from another MB hobbyist.

 

YOUR RPM SWITCH COULD BE GOING BAD???IF IT STOP COOLING ,,STOP ENG AND RESTART IT IT WILL COOL AGAIN BELTS OR BELT IS SLIPPING OR COMPRESSERS LOCKING UP..MAKE SURE YOU FANS ARE WORKING JUMP THE PIGTAIL SWITCH ON THE DRYER TO SEE IF IT COMES ON...ENG.FAN SHOULD KICK ON TOO.

 

YES THEY HAD A RECALL WAY BACK WHEN BUT YOURS IS ALLREADY UPDATED,,,,,190 HAS THE WORST A/C/OF THEM ALL ..EXCEPT THE 116 CARS...