Toshbar

In my previous two vehicles, I have been able to defeat the AC compressor in the defrost and defrost/foot modes. I am wondering if that is possible in my 2005 lariat w/auto climate. In my 2004 Honda Accord, there was a button pushing sequence that changed the AC system to not cycle the compressor when defrost and defrost/foot was selected.

gone postal

Why would you want to? The system cycles the AC compressor to keep the system lubricated. It extends the life of the compressor and ancillary systems, and has no effect on the heating/cooling whatsoever.

Toshbar

It burns more fuel and puts increased load on the engine when oil is coldest.

I just ran through the factory service manual for the climate control, and the compressor will not come on below 35*F, so it really isn't that big of a deal since the air temp will rarely be that high.

Mod (Ret.)

^^ This. The minute amount of fuel the clutch would use is much less then the cost of A/C repair and/or service if it were to dry out from several months on no usage. The engineers got this right.

PerryB

The reason for running the a/c is to make the evaporator cold. As the defrost air is pulled through the cold evaporator any miosture will condense out. Now the air blowing on your window is warm AND dry. Disabling the a/c compressor will have a negative impact on defroster performance.

screamineagle

This is correct. Basically it decreases the chance of your windows fogging up.

The other replies make sense too. It does help by keeping the system lubricated.

Toshbar

I know what the AC does. I want a defroster only option. Note the difference between defrost and defog.

Can anyone help me do that, or am I going to have to figure it out myself again like my 2wd low range switch......

scobar

iTrader: (4)

This. I like a clean, clear windshied.

Unplug the pigtail from the compressor. This will give you just defroster only. I'm sure there is also a fuse for this function as well that could be put on a toggle switch.

When you say you want someone to help you, are you meaning come over and do it or?

Toshbar

What I'd really like is for someone to tell me which wire coming out of the EATC is the compressor signal, so I can intercept it with a toggle switch like I did in my Jeep.

Mod (Ret.)

^^ A test probe or multimeter will help you with that.