85 300d A/C not working
 

I am working on an 85 300d for a friend (oil/filter/fuel filters/etc). He told me the a/c was working great, then quit one day.
I checked the fuse panel and found the fuse for the blower had blown. I replaced it with a new fuse (25a - blue) and the blower works now, but the compressor does not engage.
Are there any other fuses/relays that I need to check?
I've searched this forum, but could not find any answers.
Thanks.......Dennis

I'd be happy to help, but there's got to be about a half dozen recent threads about A/C and compressors. Scan those and you'll find some possible causes.

More specificity is better when asking for help. What fuse did you replace? #8, or the external fuse holder, if any?

Have you looked at the wiring diagram? Or the fuse diagram? Do you have a voltmeter?

How long ago did it quit?

R12 or 134a isn't necessarily relevant to the compressor not engaging right away, but it may be relevant to whether the system has a charge and how you check it.

Just replaced #8 fuse.

Feel your pain...
 

I, too, am troubleshooting an 85 300D A/C challenge...here are some places to start that I'm currently going through...

Low Charge switch (on receiver) keeps compressor from engaging due to low freon - easy check with meter for electric side, check pressure in system for appropriate charge.

Evaporator switch kicks compressor off if evaporator temp <32* to prevent icing of evaporator - easy check w/meter

Throttle position microswitch on valve cover - easy check w/meter

KLIMA relay located just in front of fuse box / brake booster under a plastic cover, digests info from kickdown, throttle, pushbutton unit, low charge & evaporator temp switches to determine whether to engage clutch on compressor - wish it was easy to verify working order, I havent been able to find a good wiring diagram or test procedure specifically geared to 1985 300D / KLIMA # 001 545 74 05

Push Button Unit - poor/broken internal solder connection(s)

Climate control unit (solid state unit behind glove box) poor/broken internal solder connection(s)

Most all of these have extensive threads in the forums, that said I'm still diagnosing min. When/if I figure it out I'll post the results.

I'm all ears for where else to look, forum guru's...:rolleyes:

300dOwner,
Thanks for your reply. My brother will bring some tools (meter,etc) tomorrow to help me diagnose the problem. I will go down the list you provided and I am confident we can find the answer.
Like I always say, "if you put 1-1/2 heads together, you can usually come up with the right answer".
One guess who is the 1/2 head this time.......Dennis

About $700 later, the A/C blows 32 degrees at the vent - bbrrrrrrrrrr
Thanks for the help.......Dennis