why does a/c not turn on

[dgrollo]

I looked at previous posts and did not see an answer to my question. Hope someone can help. I have an 84 Carrera and have not used the totally stock a/c for probably 10 years. After this very hot summer I tried turning it on and there was no sound of anything working fan, compressor etc, no air from the vents. Question is if the system is empty of coolant will it turn on? Also I have checked fuses but are there other areas to look at? Appreciate any help.

[kyle242gt]

I'm in the same boat, hate to say, you just need to start digging.

The fan should run irrespective of pressure in the system.

If I was able to get off my butt and do anything about it, I'd:
verify fuse
verify power to/from fuse box
investigate wiring diagram, see if power goes to switch or to fuse first.
trace wiring, find the relay, see if there's power to/from it
jump power to fan, see if it comes on
depending on where failure is found:
remove fan
remove switch
remove relay
... disassemble, inspect, clean, reassemble, pray.

These cars are pretty simple and hail from the days before computers control everything.

So saddle up, cowboy, and go wrangle some electrons. RAWHIDE!

[SReppel]

I recently posted with the same issue. My 78 SC evaporator fan suddenly quit, restarted and then would not come on again.

Took me awhile to trace out the wires from the Relay in the smugglers box to the fuse box. I used a meter to check voltage and trace them out and found that the fuse was not making good contact and was also in the wrong place and wrong amperage (was red/should have been blue)

One of the things I did to check the blower was to use a jumper wire from the black wire on the relay (#85) to the red/white wire going to the blower motor to see if it would come on. It did and I could also hear the clutch for the Compressor kick in. With the ignition on the black wire should be hot (12V) when checked to ground.

I also changed out the old relay and put in a new one that I got at a local auto parts store.

Working fine now, hope this helps. Kuehl gave me some good advice also that helped me troubleshoot the problem.


Scott
_________________
78 911 Targa, 01 Honda S2000

[kuehl]

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_AC.jpg

[dgrollo]

best forum out there always get good advice. keep on Porsching