DE-link "defroster-linked A/C"

[AlaricD]

I found this thread regarding "de-linking" the defroster from the A/C, such that one would be able to use the defrost position without the A/C coming on, yet being able to still turn the A/C on with the dashboard button. Here, it applies to the 2005 Tacoma. Would this also apply to the 2001 Corolla LE? (I'm not really interested in signing up for the forum linked in that thread just to see the pics; maybe someone else here already is a member or knows about this subject already.)

I'd prefer manual control over the A/C so I can have forced air through the defrost vents without wasting fuel from the A/C. I know the rationalizations for linking them: A) It clears the interior glass faster and B) it ensures the A/C is used frequently enough to keep seals from drying out.

I could use the defroster position independent of the A/C on my '76 Corolla Wagon DX, my '86 Corolla, and can do it in my '95 Previa-- so why am I not 'trusted' to make this decision on my '01 Corolla?

[GaryGoatse]

The a/c fluid doesn't get used up lol. It is a sealed system and using it regularly is a good idea and yes it will remove the moisture from the air very quickly. If you run the defrost with heat and no a/c you will notice lots of fog. The a/c fluid leaks out over time and needs to be charged every so many years anyways so it's no big deal. If it really bugs you i think that you could wire it up seperately but i'm not too sure about the exact steps and i don't know if that thread would apply to a corolla. If you are keen with electronics then give it a shot because it is possibly if you can get a wiring diagram and know how to solder:P I might be able to get you a wire diagram when i go to work tomorrow and see if i can help you but it isn't really that big of a deal to have the a/c coming on lol just think about it

[AlaricD]

The a/c fluid doesn't get used up lol.

Yes, I know-- I know it leaks out due to injury to the system or to the seals drying out due to infrequent use.

I didn't get a lot of fogging in those older cars or the Previa; I can always turn on the A/C manually.

I just don't like the increase in fuel usage from A/C usage and the ability to control it all myself. Heck, I already disabled my DRLs just to be in control...

[GaryGoatse]

lol so its just a control thing? yeah i know for the first few months i thought that it only turned on the a/c when i pushed the button in but i leave it on defrost all the time so i guess it was on all the time. I tried findin a wiring diagram for the system but its pretty tricky. Ill print it off and trace it sometime this week to see if we can put a switch in there somewhere to manually control it, it would have to be something that is triggered when you put it onto defrost, so maybe dissasemble the unit and remove the switch that does that? Because it would have to be two parallel switches, so if either the a/c button is turned on or the defrost is turned on then the a/c will turn on. Dissable the switch in the defrost and it will only turn on with the a/c button. I'll see what i can find

[AlaricD]

Originally Posted by GaryGoatse

I'll see what i can find

I'd already messed with the knob that selects the vent/floor/defrost positions. I think there's a switch somewhere else that's not directly connected to the knob itself.

There is a small harness that plugs into the blower assembly (if I recall) that seems to have more wires than it needs to just control fan speed and such. Maybe it's just one of those that is the signal from the Defrost position to turn the compressor on. I may fiddle around with that to see which one it is by trial and error-- and will do a photoessay of it if I find out. Surely I'm not the ONLY control freak around here...

[fishexpo101]

I'm pretty sure this would also apply to our generation of Corolla. I've seen it done on a 9th gen Corolla (disconnect control link) - I would be quite surprised of Toyota completely redesigned the system from the ground up between the 8th and 9th generation.

It was on my to-do list for a while, just be saddled to too much work from other projects. If you have a chance to do it - please post up your findings.

[AlaricD]

Originally Posted by fishexpo101

I'm pretty sure this would also apply to our generation of Corolla. I've seen it done on a 9th gen Corolla (disconnect control link) - I would be quite surprised of Toyota completely redesigned the system from the ground up between the 8th and 9th generation.

It was on my to-do list for a while, just be saddled to too much work from other projects. If you have a chance to do it - please post up your findings.

If you have a handy link for the 9th Gen mod, I'll take a look at it and see if it all looks familiar. I won't sit on my hands waiting; I'll also look around myself for it. It looks like this weekend MAY be a good time to do it, as the weather's warming up but it's not obnoxiously warm yet.