W124.128 300D A/C Questions - PeachParts Mercedes-Benz Forum

JamesDean · #1 04-09-2013, 10:16 AM

Hey everyone,

So when I bought my 300D back in July of last year the ac was working nicely.

The previous owner had it converted to R134A sometime in 2010. It has the quick connect fittings, label etc. It was doing a nice job of cooling when I test drove it as well. I was pleasantly surprised.

I went to kick on the a/c yesterday and I get no engagement of the compressor clutch.

Now I know that could be either no voltage or low/no refrigerant. I'd like to check the voltage at the coil first but I couldn't see an easy to access test point/connector. I figured I'd ask here to see if anyone knew of the best point of access.

Assuming the clutch is getting proper voltage, I might be low on R134a. I know most of you dislike using 134A in these R12 cars but for the time being that what I've got and I'll stick to it until my 190E is ready for daily driver duty. My question is..If I buy a few cans of 134A what pressures should I expect to see on my manifold?

Do I just follow the 134A pressure/temp chart? I know you are supposed to use less 134A when in an R12 system or something along those lines..

I was also going through the fuse box and I found that fuse "D" was missing. The sheet on the box lid indicated that D was for the aux fans.. Interesting. Maybe I removed it..I'm not sure. I re-did the whole fuse box with nice copper fuses anyway.