I realized today that my A/C compressor in my 77 280z is on all the time. even though if the blower inside is off, I could still feel a little bit of air (very cold air).

1.) I know this is not normal for the compressor to turn on all the time. I checked all the connections, they seems to be fine. Is this bad for the compressor to be on all the time? it seems the clutch is not working or is there something i need to replace, like a relay?

2.) Also, the a/c is really cold in the morning compare to in the afternoon. Not that cold compare to other cars. Does this mean that I need to put an electric fan in the condenser?

Need help on this one.

Also, the heater does not work, which I don't really need in California.

Thanks

You should have an A/C switch somewhere in the car to turn it on and off. Most commonly, the dealer-installed switch seems to be under the drivers side dash or on the side of the center console. Those switches are a knob that turns to supposedly adjust how cold the air is or to turn it off. Of course, if you don't have a switch, that is likely why it is on all the time.

I am sure someone will post a photo of what one looks like soon (I don't have one handy).

Cheers,

Doug

The switch contacts in the AC relay have been “welded” closed. You can replace it or remove the cover from the relay and clean the switch contacts. Common problem. I have been putting a 0.1uF film capacitor across the points. This will reduce the arcing which creates the welding.

The AC compressor must cycle on/off in the S30's. Otherwise you will freeze up the evaporator coils. The early cars lack a POA valve which prevents evaporator icing.

is this bad for the compressor that is always on? if winter arrives, can i just remove the belt and leave it until next summer. won't that hurt?

i will try and look for that switch and the relay underneath the dash.

Thanks for your help

i will try and look for that switch and the relay underneath the dash…

The AC relay is not located under the dash. It is located on the small AC bracket with also holds the vacuum switches and the check valve.

…is this bad for the compressor that is always on?

Having the compressor on all the time will only cause un-necessary wear and places an additional load on the engine.

… if winter arrives, can i just remove the belt and leave it until next summer.

I can’t understand why you are putting off a repair that will take 10 minutes to fix? And, BTW, the easiest way to disengage the compressor clutch is to simply unplug the blue wire going to it!