I am trying to determine why my A/C on a 1983 300D Turbo does not work.I have noticed a few things that I know must be replaced 1.My internal fan blows only after I have removed it (I assume the brushes are worn. 2.My vents don't open and close.I have noticed that when the fan is working the vents seem to work also (I assume some kind of vaccum leak maybe)3.At the A/C compressor connector there is no voltage the when the A/C switch is on in the car.I am trying to determine the flow of operation.Also how can I tell if this car already has the refrigerant upgrade done.

Any advice would be appricated

Roboman 2nd Benz owner
Gotta love thse diesels

A/C Problems...
 

I have a 1984 300D Turbo with CA emissions. I am having problems with my A/C and have found that my compressor will not come on because I am low on R-12. There is a pressure switch that measures the charge/amount of R-12. It is located behind the right side headlight assembly. If it is too low, then the Compressor Clutch is not energized. To test this I went to the switch with a jumper wire. With the car running, I jumpered this switch momentarily and heard the clutch kick in and RPM lower. I will be having my system checked. I have been told that it will cost about $250 to have the system leak checked and flushed, and a new Expansion Valve, Dryer, Oil, O-Rings and R-134 installed.

As far as the center vents, mine don't come on with the A/C not running. I will wait to troubleshoot that once I get the A/C up and running. I might have to go into the Climate Control Box and resolder it, but that will come later in the troubleshooting process.

wjpelka,

Only $250? That's a great price. I just had a mechanic do EXACTLY the same on my vehicle. The All-Data labor time on the Expansion Valve replacement is 1.8/hrs and .5 for the Reciever dryer. Then my mechanic charged $129 for the vacuum and fill.

Works great now!

Make sure that you aux fans are working correctly as well.

Willy

I bought some r-12 last summer for $25 for a 12 oz. can. If you system has a slow leak, why dont you just put some 12 in? Also, has anyone out there had any problems with the r-12 conversions? I know the old oil is incompatible with R 134. DB