A/C not coming on.
 

Just got this well used C220, 123K,( no manual where can I get one?) and the ac compressor doesn't kick in. The climate control seems to work on heat and all functions. I thought maybe freon was low and hooked up can of freon but nothing. I checked fuses and all look good and intact. What should I check next?

"hooked up can of freon and nothing"

What does this mean? If you are using a suicide hose and freon to "check" the system, this is the wrong approach. You need to connect a set of gauges and properly diagnose.

Most likely the system is low which causes the low pressure switch to interrupt the clutch circuit for compressor protection.

Good luck,

please correct me if I"m wrong
 

Shouldn't the addition of new refrigerant provide sufficient pressure to activate this switch? Is there any sort of reset function built into the system?

Yes, I too thought if a AC system was low on freon just by hooking up a can would activate the switch if that was the case. I did this last week on a Ford and it worked fine(and several others over the years)

Yes, in most cases, I suppose that one can would engage the low pressure switch, but this is not good troubleshooting. You need to put on the gauges to know what gives with the system. Otherwise your flying in the clouds with no instruments.

Good luck,

Thanks for the replys. I'll have to find someone with gauges. Would it be wise to try jumping the pressure switch to see if the compressor starts? I need a manual for this thing.

Don't be impatient. There's absolutely no reason to jump anything until you check pressures and see where you're at.

If you have good pressure and you still don't have clutch engagement, use an ohmmeter to test the switch and troubleshoot the circuit properly.

Good luck,