Good Question. Whenever you engage the Defroster, the A/C compressor is engaged as long as the outside temperature is above freezing(I think). The compressor does not engage in temperatures below that. I use to think this was a really dumb idea for the A/C Compressor to kick in when I wanted to Defrost/Clear the Windshield of ice or condensation. But then I remembered the years I use to drive constantly wiping the condensation off the windows. Those days are virtually gone for me since I use the A/C (with Heat) to take the condesation off all the windows(inculding the Windshield). The Rear Defroster handles the back window. So, Yes, you really don't need the A/C to DEFROST the windshield, but it does a better job of clearing the condesation that forms inside the car.

Thanks for the quick reply.

Well that would make sense of why when I pull the A/C fuse out my whole heating system doesn't work. I tried that to take the compressor "offline" since the whole a/c system isn't even charged.

If your right, then even bypassing the compressor with a differen't belt won't keep the car from trying to access the a/c when I turn the heat on? Could I not just cut all wires to the compressor, or will that give an error code all the time?

I might be missing something here. I understand that your A/C does not work. But as long as the pulley on the compressor is running freely then there is no need to bypass or cut the lines to the compressor. If the system is low on freon or r134, then the system is not supposed to engage the compressor(sort of like a fail safe not to cause damage to the system). If that'* your case, and again, the belt is moving around the pulley freely, then there is no need to cut any wires or replace the serpentine belt. Drive On.

interesting. My system definately isn't charged right now...

Here'* why the AC is used for defrosting:

Cooler air holds less moisture. It uses the AC to cool the air and cause water to precipitate out, then it heats it up to increase it'* water holding capacity, then blows it on the windshield to take the condensation off it.

I bypassed the AC compressor on the 93 SE because the clutch failed and it made horrible horrible noises.

I ran for about a year with no AC on the car. The rear of the AC compressor was leaking so there was no freon in the system. My clutch was fine so I left it on there until I got around to fix it.


I really doubt that you loose much if any HP by having the compressor clutch still running on the belt, even with the compressor not working.

if you were to run a shorter belt, would you be able to clear the compressor?

Did a check and it'* a 73 inch belt to bypass the a/c pully. Just need to get my thermastat cover fixed so I can go buy one and try it.

Because the compressor pulley is clutched, you won't really free up that much power. On the other hand, it is one less thing for the belt to spin, and it looks like a heavy pulley. Less rotating mass, so the engine should rev up ever-so-slightly quicker with the bypass belt. I doubt that you'd feel a difference, but there will be some minute gains there, in both performance and mileage.

Just replaced the belt with the new one by-passing the a/c compressor pulley. If anyone wants to know, a 73" belt is the perfect size. Now I might just be going nuts, but the car seems to start easier. I did notice the a/c pully turned hard and had a rubbing type noise when I turned it by hand, so that might of have something to do with it.