The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 3 Fan Relay + VA

**First c10** · 01-11-2020, 10:43 PM

So the grounded trinary “Blu” has a diode to the high and low side of the pcm so the fans go to high when the trinary switch see’s pressure? And if the pcm tries to turn on the fans it doesn’t change? Will there be any codes in the pcm as the high and low signal wire will see ground when ac is on and the pcm isn’t calling for fans on? I Ask because I can’t remember what I did.

01-11-2020, 10:43 PM	#2
First c10 Registered User Join Date: Dec 2012 Location: Los Banos CA Posts: 2,706	Re: 3 Fan Relay + VA - Diagram So the grounded trinary “Blu” has a diode to the high and low side of the pcm so the fans go to high when the trinary switch see’s pressure? And if the pcm tries to turn on the fans it doesn’t change? Will there be any codes in the pcm as the high and low signal wire will see ground when ac is on and the pcm isn’t calling for fans on? I Ask because I can’t remember what I did. __________________ 1956 Chevy Bel Air 2 door 1956 Chevy 210 4 Door 1970 K20 LWB project the Hulk build w/Supercharged 4.8L-ly2/4L60E HULK BUILD 1970 C10 Yellow/White Deluxe LWB w/ 5.3L-LC9/6L80E 1968 K10 LWB Dark green my son calls it "THE HULK Jr"HULK JR SOLD GO GO!!!