72and86

My latest purchase is a 1981 Vette with non-working AC. I see the connector to the compressor is really bubba jury-rigged and trashed.

I see 2 CONNECTOR replacements online, one WITH the diode and a pigtail WITHOUT. Which do I need for my 1981?

See:
https://www.ebay.com/itm/GM-R4-AC-Co...item3abf32d2d8

speedreed8

Antz81

No sign of a diode o. My factory harness or the replacement either.

DUB

I have never seen a diode in the connector for the A/C compressor on this year model.

DUB

TimAT

The diode was used to keep the electronic "pulse" from the magnetic clutch from going back to the ECM where the a/c is really controlled from on some years.

72and86

Does this apply to the '81? Does it even have a ECM?

DUB

I STAND CORRECTED and had a brain fart not realizing I was replying to a 1981 Corvette.

YES...there IS a diode in the connection . This is a FACT! And It is confirmed in my factory wiring diagram.

YES...you car has an ECM ( computer). Or at least from the factory it had one.

DUB

72and86

An ECM in a carburation car? Really? 1981? What was the first year with a ECm?

DUB

YES...really.

Your carburetor has a TPS ( throttle position sensor) on it...along with mixture control solenoid. For this reason...IF you go and begin to fart around with your idle adjustment on your carb...the TPS will more than likely need to be adjusted also

As far as I know 1981 is the first year for an EMC. But I had heard that some 1980's had them...even though the service manuals do not show anything about it. I have heard that some may have ECM's in them.

DUB

lars

That's correct. All the '81s had ECM-controlled carb APT along with fully ECM-controlled distributors, eliminating centrifugal advance and vacuum advance. The California 1980's (all had 305 engines) also had ECM control on the carbureted vehicles a year before the Federal cars got it in '81.

Lars