A/C Problem

[Limestone Cowboy]

Hey folks, got an issue and a question..

Vehicle is an 02 SR5 with low miles (78K). My AC works really good sometimes, especially since I recharged it recently, but I have an odd intermitent problem that involves the T-Stat contol (I think).

It seems most prominant from a cold start or during the first 20 minutes of driving, where the cold air starts cold, but eventually tails off. If I twist the temp control to lukewarm and back to cold, it will return to being ice cold for a little while.

This morning I was driving without the radio or AC on, and I could here some noises behind the dash that seems vacuum related, as if something in the AC control is "hunting" around. If I twist the temp control with the AC off, I can alter this noise. Is this a problem anybody has had before? My knowledge of auto AC systems is self admitedly low.

 

[Limestone Cowboy]

ok, so I'm quckly learning some stuff here. I guess my problem is the A/C servo. This was confirmed by crawling under the dash to actually watch it move around... or "hunt" for something. That's the noise I'm hearing. Assuming this part is dumb and moving like its told to, is there any part upsteam that might otherwise be the problem?

 

[TheDurk]

ok, so I'm quckly learning some stuff here. I guess my problem is the A/C servo. This was confirmed by crawling under the dash to actually watch it move around... or "hunt" for something. That's the noise I'm hearing. Assuming this part is dumb and moving like its told to, is there any part upsteam that might otherwise be the problem?

Odds are its the servo. Somewhere there is a DIY fix where you remove a plastic gear and rotate it 180° to give it new life.I never bookmarked it because mine is manual.

But there is a diagnostic routine built into those digital controllers; the error codes read out on the temp screen--no scanner needed. This is explained in the FSM. Go to Complete Repair Manual at the link below, and then go to the very bottom. It's in there.

1996 to 2002 Toyota 4Runner OEM Repair and Wiring Manuals

 

[Limestone Cowboy]

I've been looking at the FSM link, and there is a damper position sensor within the 'air inlet servomotor'. There's also some test procedures that will require the DVM.. next weekend. Thanks.