What's this relay?

[Davidf]

Originally Posted by hdff

ok the wires are orange , green and red so by that schematic it is the anti dieseling relay. was that something that was exclusive to Ac cab trucks? looking in the classic parts book I don't see one. do they not sell one? would a horn relay work if needed? can someone explain exactly what this does. I know what dieseling is but what does this do to prevent it?

and wow I think that is the 1st electrical schematic that I have understood, all of it made sence to me...... thanks vettevet!!

Yes, the anti-dieseling relay is exclusive to the a/c trucks. No, a horn relay wont work, not will a fan high-speed relay work. You can still find the relays on Ebay. I believe there was a Service Bulletin related to the anti-dieseling relays that a diode needs to be installed at the voltage regulator (Field terminal?) so that back feed electrical current does not burn out the anti-dieseling relay. I have all the wiring correct on my truck, with new relay, and can't get it to work...gave up.