Mercedes-Benz Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I recently bought a nice 78 300CD. I had the A/C recharged by a local shop and the A/C blows cold, but seems to turn off by itself. I have the temp set to the lowest setting, but it seems to turn off while I am driving and randomly turns back on. Ideas? Is there a way to convert the auto climate control to a more manual system where I could have control over when the A/C is turned off?
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
Sometimes it turns off and then comes back on one more time before shutting off completely. Sometimes it will not start back up until I turn off the car and start it again and other times it will not come back on no matter what I do.
 

·
Registered
1978 280ce euro found dead on Ebay
Joined
·
1,805 Posts
I have the manual type Ac and I couldn't get mine to turn on at all. I endend up wiring the compressor to the blower motor so when blower motor is on compressor is on.

It sounds like your is working correctly If you have it on lowest setting it's going to be cycling often. Does it also cycle if you have it on MAX.
 

·
Registered
77 240d, 02 Ford F250 V10 (7mpg), 05 GMC Denali (The Baby Hauler), 2000 BMW 323CI (was my Bros car)
Joined
·
817 Posts
You might have a bad or going bad AC cut off switch. Here is what it does:
"To prevent compressor failure due to pressure loss and to protect warranty.
Shuts off at 395PSI to prevent compressor from freezing up"
It mounts by your receiver drier.
 

·
Registered
77 240d, 02 Ford F250 V10 (7mpg), 05 GMC Denali (The Baby Hauler), 2000 BMW 323CI (was my Bros car)
Joined
·
817 Posts
You might have a bad or going bad AC cut off switch. Here is what it does:
"To prevent compressor failure due to pressure loss and to protect warranty.
Shuts off at 395PSI to prevent compressor from freezing up"
It mounts by your receiver drier.
Maybe they didn't put enough r134 in?
 

·
Registered
'82 300D
Joined
·
1,279 Posts
Get a High/Low pressure switch. If it is the original switch it only cuts out at low pressure.

You would need to find a Euro w123 of the same vintage to do a proper manual conversion.
 

·
Registered
1978 280ce euro found dead on Ebay
Joined
·
1,805 Posts
Get a High/Low pressure switch. If it is the original switch it only cuts out at low pressure.

You would need to find a Euro w123 of the same vintage to do a proper manual conversion.
Can you replace switch without having to depressurize the system. I think I got a bad low pressure switch but don't want to lse my R12 freon in system.
 

·
Registered
1979 280CE
Joined
·
6,118 Posts
I think you have a vacuum leak. Mine never just turns off completly(I have the same system as you), the blower will cut back and speed up alittle(not often). The blower shouldn't ever just go off unless you turn it off via the switch and push button.

Do you ever hear anything clicking behind the dash when it goes off?
 
1 - 10 of 10 Posts
Top