To get my AC to come on I have to give my car a good rev up. If I take off slow and drive slow it will stay off the whole drive. From a cold start it I gun it it will come right on. Cold engine and all.

I jumpered the two switched, low pressure and the one by the accelerator, I changed relays, topped off the R12. Once it comes on it works fine.

I drove home the other night and never accelerated forcefully and it stayed off. The next morning I took off fast and it came right on. Now I just turn it on by gunning it right after taking off.

Any ideas?

It might be cracks in the climate control pushbutton unit / computer board. The vibrations from high rpms might "fix" the connection and get the system to command the compressor to turn on.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

May be normal as some will not allow the compressor to engage until rpm comes up off of idle. It's a feature to eliminate the load of the compressor during starting.

I should have said I also replaced the ACC unit with a rebuilt one. I guess if it is normal I will just have do drive a little more aggressively.

Vacuum leak.

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Does the tach work?

I don't believe an 82 has a clima / rpm sensor relay.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

clutch air gap is too large.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

'82 may not...

I change my answer to a loose connector at the compressor.

I was just watching a video where someone explained this. He tested it by switching on the AC then poking the clutch plate with a tool, which gave it enough assist to be pulled in.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.