Well, I've never liked the fact that the AC compressor runs in the defrost settings. As you can see from this diagram, it is supposed to run in the AC, Max AC, defrost, & defrost w/floor settings.
http://i103.photobucket.com/albums/m126/webmastercharlie/acwire.jpg



Well, in the winter I often just leave the selector in the defrost settings, to keep some heat on and air movement. But, I don't want to have the compressor running. So, I installed a bypass switch. On the rear of the panel, simply cut the purple wire, which comes off of the harness behind the selector switch, install a few extra inches of wire on both halves, and put a switch in. So now, I can switch the compressor off manually. When it's running I get an average of 1-2mpg worse, and honestly, I like to get the best mileage I can.

The switch-it's where the stock fog light button would be, but I don't have that. It's sideways, since the switch was a little too tall to fit in the space there without cutting out the clip for the fog light switch. I just didn't feel like messing with that..so it's sideways.:D
http://i103.photobucket.com/albums/m126/webmastercharlie/acswitch.jpg

It's been like this for a few days now, and haven't had any problems with it. I don't see why there would be, since you are just stopping the signal from reaching the AC compressor cycling relay.

Overall, I'm very happy with it. If you run in defrost settings, you could do this and pick up an extra MPG or few.

Total cost, nothing for me, since I had an extra switch and wire. Otherwise, it would be about a dollar.
The gain, about 1-2mpg from what I've seen so far.

You sir, should be rewarded for this. In theory, your modification could save millions of dollars over time, worldwide.

:thumbsup::thumbsup:

I can't claim it to be my idea, I had read it on here a while back, but I couldn't find the original poster.

On the other hand, in some climates like ours with 8-10 months of rain
you can be plagued with the inside of the windows fogging up.

You sir, should be rewarded for this. In theory, your modification could save millions of dollars over time, worldwide.

:thumbsup::thumbsup:

That would save a lot more gas than "airing up your tires."

I need to add a couple of switches to control the recirculate function, that only happens in AC max now.

Charlie, I see that your name is green now. When did you become a vendor, and what are you selling?

Very good Charlie, shackles anyone?

Turn it on every once in a while to lubricate the system.

will this work on a 02, and is the wire purple in the 02 also. i have notice
my gas mileage going down since its began to get cold. i always have the heat on defrost/defrost floor. hopefully this will solve the problem.