Air conditioning Anti Dieseling wire harness
 

I just got a 1972 Chevy blazer with factory air. I want to replace all the wiring with new harnesses from M&H. I've never had a 67-72 with factory air. I came to the Ac harness section and I have two choices. Non anti Dieseling and anti Dieseling.

Can someone enlighten me on what this is? Thanks!

Re: Air conditioning Anti Dieseling wire harness
 

I believe the '72 came from factory with an anti-dieseling relay installed. It does exactly what it says...briefly engages the a/c compressor when engine turned off in an attempt to prevent the engine from dieseling or running on. Mine doesn't work even with a new relay and good wiring...not sure why.

There should also be a diode at the voltage regulator connector to ensure the anti-dieseling relay is not back feed with power which could damage it.

The relay would be mounted on the lower lip of the dash just to the right of the power socket/HVAC control panel.

Re: Air conditioning Anti Dieseling wire harness
 

here is the anti dieseling relay on my 71

Re: Air conditioning Anti Dieseling wire harness
 

Here is the circuit diagram.



Attachment 1495568

Re: Air conditioning Anti Dieseling wire harness
 

This is all awesome. Just waiting to clear out some garage space so I can start taking out the wires. Sit down with a bundle of wires, solder, and some beer. Sounds like a good afternoon!

Re: Air conditioning Anti Dieseling wire harness
 

Does anyone know what order the wires go in on the Ac/heater assembly? I put in a new under dash harness but my Ac harness is pretty butchered.

Re: Air conditioning Anti Dieseling wire harness
 

Here's a picture behind the control switch.