Question about A/C on my 190E
 

Have a funny A/C problem on my 190E.... It seems only working in the morning and evening time. Only not working in hot afternoon.

I replaced the evaporator last year. Checked feron is enough in the system. Replaces pressure switch, dryer, aux fan switch when replaced evaporator last year.

I tried using 2 different A/C relays. Still have that problem.

It seems the compressor not kick in.

Double check the belt tensioner is good... Belt doesn't slip. Anyone can guide me out what i should look for? thanks

Have you hooked up gauges to determine pressures? If overcharged, the pressure can actually be *too* high which will trigger the high-pressure switch and prevent the compressor from running. The pressure may just be lower in the morning and evening (due to cooler ambient temps) which may be allowing the compressor to run.

Just a thought...

Yes, i bring it to repair shop to check the pressure. They said that the pressure is fine.

I used it almost whole year from last summer until recently. It was totally 100% working.

I don't think so that is too much feron in the system.

any time i have had an issue like this....it was not enough refrigerant.

ok! i will try another shop.

three other things you might check.speed sensor on compressor might be reacting to loose belt on engine,aux fans may not be operational,[and they need to be on hot afternoon]and there is an o/heat cutout switch in the thermostat housing that may have gone bad.

Does anything work intermittantly?
Blower/compressor? Does compressor come on and not the blower....?
Check the CCU in the dash...the push buttons. They just wear out.
Sounds like you have either checked or replaced everything else....

Blower is 100% working for sure!! I have another used CCU at home. Put it on, still the same (i don't think so that is CCU problem).

Very like David S Poole said the aux fans may not be operational and cause high pressure in the system. That cut off the A/C compressor.

Just updated my A/C problem... I used engine degreaser to wash through compressor (specially the wire connector) and condenser.

Cleaned all dirty on the connector.

The A/C system was working perfect yesterday. Drove over 4 hours, stop and go traffic and no cut off the compressor..

Will try one more day and report the result later.