Defrost with NO A/C (1 Viewer)

[cruzerDave]

98 LC - anyone found a way to disable the stupid A/C-on-when-defrosting? I like to decide when things happen on my truck, and when it's 9 outside and I need to keep the wipers from freezing I would prefer to NOT have the stupid A/C turn on just because I want heat on my window.

It sounds like pulling the fuse will also kill the blower, so that's no good. Am I down to disconnecting the A/C pump wiring connector? What about TechStream?

 

[benc]

The windows will fog up pretty bad without the ac on, the ac dries the air coming through the defroster.

 

[cruzerDave]

Ben - totally understood, and I'm happy to push the A/C button when that does start happening, but I can run the defrost/floor split setting for 10+ minutes without fogging in our current weather conditions so expect to get some good, concentrated heat on the window for at least 5-8 without A/C before fogging... It's just dang annoying!

 

[2001LC]

There may be a way through Tech stream, IDK. But not a good idea. AC needs to run monthly, at least two minutes at a time for lubrication purposes. Better just to turn off AC after two minutes, and set to fresh outside air which in most climates will reduce or eliminate fogging. Also bad idea to let idle for 10 minutes (per OM). If gasoline usage is a concern avoid using cabin fan for heating & cooling.

Tip: Don't heat windshield and wipers will not freeze, in dead of winter.

 

[Abigail]

What's the problem with just turning the temp up so the "A/C" is blowing warm and dry air?

I get it, control, but sounds like a pain to change.

 

[cruzerDave]

What's the problem with just turning the temp up so the "A/C" is blowing warm and dry air?
I get it, control, but sounds like a pain to change.

It's just an annoyance - yes it works fine, but the engineer in my chafes at the idea that I am using energy to try and cool air already frigid, to then heat it back up, all for no reason...

 

[NorthernXS]

you could just throw a toggle switch on the power wire to the compressor clutch/coil. That would allow you to interrupt the signal to the compressor itself and keep it from coming on.

 

[benc]

I believe the plug on the condenser that you likley encountered when installing the bumper would be an easy spot to tie in a switch. I believe when that is disconnected the compressor will not come on.
You may want to unplug it and see how the defrost works without the ac first. In my climate the defrost was almost worthless without the ac, especially if there was more than one person in the car.

 

[re_guderian]

Living in AZ, I'm certainly no defrost expert, but I've noticed that even when I punch the AC button to "off" I still get a ton of drainage on the driveway out of the condensation tube from the evaporator. I haven't cared enough to get under and see if the clutch is really engaged or not when the AC dash switch is off but the defrost mode is selected...