I have just replaced the evaporator on my daughter's '89 190E 2.6 because it finally gave out and ALL freon was gone ! I chose to move to R134 for obvious reasons and with disconnecting the evaporator lines I drained as much old R12 oil out as possible, including emptying the drier of all oil, I think I'm ok now... My problem is when I upgraded the cold side connector and hooked up the R134 canister, I thought the freon would go into the system and eventually the compressor would come on an start to charge the entire system. That's not happening ? All I have right now is the Low Side tube pressurized with the start of the can of R134 .How do I get the compressor to begin to engage so it will start accepting the cans of R134 ? Any help would be greatly appreciated. Thanks, Padge

 

Cleaning up messages a bit today.... trying to answer questions that noone seems to answer....
Here's an update, assuming all A/C functions were OK prior to parts replacement:
In order to RECHARGE the new system...
1. For those that have a 190E with KLIMA Control behind the battery, remove the
KLIMA relay and "jump" the 15 and 87 pins and start the car with A/C on high,
and FREON ready to go in the LOW SIDE.
2. You should now see the Compressor Clutch engaged and turning.
3. Unload the FREON to the specified levels.
4. Turn of vehicle.
5. Replace KLIMA relay.
All should be ok now.
Good Luck,
Padge

 

Sad thing about 134a is that it's going to be phased out too. I still have the original r12 system and have never converted to 134a. I used r152a. Perfectly compatible with the r12 system without changing a thing.