Is there any way to not have the A/C pump cycle when using defrost? Once the vehicle is warmed up, it hasn't fogged up on me... and the A/C pump makes the truck quite a bit thirstier on the fuel, lol.

Tips, hints, suggestions, gremlin commands are all welcome...

Please and thanks!

 

If your compressor has that big of an impact on your fuel mileage, you've got issues larger than the compressor cycling. Even in the summer, I showed very little difference in the fuel mileage with the A/C on or off. I would really doubt that the compressor cycling as little as it does in the winter would have anything to do with your mileage.

But if you want to keep it from cycling, put a switch in the clutch circuit or just unplug the clutch.

 

Maybe I'm just used to my old Z34... Not used to all these fancy new gadgets that DON'T make things wonky, lol

But thank ya! I'll watch the mileage, and see what happens...

 

Ditto to what Swartlkk said. Unless there's something wrong with the AC, the difference in fuel consumption is negligible. You could put a switch in the clutch circuit and mount the switch on the dash, but I'd suggest living with it until spring and then fixing any problems.

I suspect you have the impression that it makes a difference, but haven't actually tested it. Gas mileage always stinks when temps are cold - and that's when you use the defrosters.

If you wanted to actually find out the difference, you'd need a two-week stretch of weather that was unchanged. Fill up at the start of week #1, use the defrosters and note the gas mileage. Week #2, fill up again, disconnect the electrical connector for the compressor clutch, drive the same places, use the defrosters the same amount, and note the gas mileage. Compare, and all things being equal in terms of your driving and the number of minutes you used the defrosters, you will be able to perceive the impact of the AC unit on your gas mileage.

I'm betting that the error of your measurement will be much greater than the impact of the AC compressor engaging occasionally.

 

Probably true, lol, I just know with my old Z34, in the summer time the mileage dropped about 4MPG when I used the A/C for a tank of gas...

Ahhhh well, I'll worry about it when I get like 4MPG

 

Using AC for an entire tank is quite different than using the defrosters. When you use the defrosters, the AC cycles on and off occasionally, but doesn't run steadily. Much less load on the engine.

 

Good to know... My old Z's A/C must've been on the way out then, the defrost would run the pump continuously...