[1chevelleofaride]

I have a 68 Malibu with Factory A/C. The Compressor wont engage when I turn on the A/C switch inside.I have used a tester and can't detect power at the Comp. leads. Also I been told that the A/C switches are vaccum engaged. There is a vaccm line hanging from under the dash.

Any suggestions are greatly appreciated.

Thanks in advance

 

[Elree Colby]

There are no vacuum operated by switches on a factory 68 Four Season A/C. There are several things that you can check. Check for power at the fuse and for a good fuse. If the blower is working you know the fuse is good. The main switch "Lo Blo Switch" is operated by the top control lever, when in MAX or any position to the right of MAX, power is switched, to the ltgreen wire, to the "Diverter Door Switch. It's on tip of the A/C box under the dash. It is operated by the middle lever and when it is in the BI Level and any position to the left it switches power to the tan wire. The tan wire passes through the firewall and connects to the low temp switch. It is mounted on the under hood A/C box. When the outside air is above freezing it should be closed sending power to the A/C clutch via the dkgreen wire. The second, black wire, is ground for the clutch.