Ac Goes "click,click,click" And Repeat.....

[TinyHero1971]

Hello All,

I own a 1994 Lexus LS 400 that has begun to make a constant "clicking" whenever the AC is turned on. The only way to make this sound stop is to increase the temperature and eventually it stops as I reach the max on the temp setting. I'm wondering if perhaps it is the vent down inside that switches from cool to heat. I know some change (canadian no doubt :) ) has slipped off down the center console, under the ashtray receptacle and am suspecting it's now obstructing something....I dont' know...just guessing. Has anyone ever heard of anything like this? How do I go about diagnosing short of tearing apart the dashboard, and if I have to tear it open, how hard is it to get it back together?

I really need to fix this as winter and summer are both unbearable without a functioning system. Thanks in advance for any insight or advice you may have!

[wwest]

Hello All,

I own a 1994 Lexus LS 400 that has begun to make a constant "clicking" whenever the AC is turned on. The only way to make this sound stop is to increase the temperature and eventually it stops as I reach the max on the temp setting. I'm wondering if perhaps it is the vent down inside that switches from cool to heat. I know some change (canadian no doubt :) ) has slipped off down the center console, under the ashtray receptacle and am suspecting it's now obstructing something....I dont' know...just guessing. Has anyone ever heard of anything like this? How do I go about diagnosing short of tearing apart the dashboard, and if I have to tear it open, how hard is it to get it back together?

I really need to fix this as winter and summer are both unbearable without a functioning system. Thanks in advance for any insight or advice you may have!

#1 clue...at max cooling or max heating ALL sensor signals are ignored and the pertinent servomotors are driven BLINDLY into the appropriate position.

SO.

You have a input signal sensor (not likely to be a servomotor positional feedback sensor since it lags but "follows" the temperature setpoint) somewhere that is intermittent.

I would check/replace the cabin temperature sensor first. It's behind "window" in the dash panel just above the drivers right knee.

[TinyHero1971]

Hello All,

I own a 1994 Lexus LS 400 that has begun to make a constant "clicking" whenever the AC is turned on. The only way to make this sound stop is to increase the temperature and eventually it stops as I reach the max on the temp setting. I'm wondering if perhaps it is the vent down inside that switches from cool to heat. I know some change (canadian no doubt :) ) has slipped off down the center console, under the ashtray receptacle and am suspecting it's now obstructing something....I dont' know...just guessing. Has anyone ever heard of anything like this? How do I go about diagnosing short of tearing apart the dashboard, and if I have to tear it open, how hard is it to get it back together?

I really need to fix this as winter and summer are both unbearable without a functioning system. Thanks in advance for any insight or advice you may have!

#1 clue...at max cooling or max heating ALL sensor signals are ignored and the pertinent servomotors are driven BLINDLY into the appropriate position.

SO.

You have a input signal sensor (not likely to be a servomotor positional feedback sensor since it lags but "follows" the temperature setpoint) somewhere that is intermittent.

I would check/replace the cabin temperature sensor first. It's behind "window" in the dash panel just above the drivers right knee.

Ok I will give it a shot and thanks so much for the valuable insight!

[SKperformance]

I would clean the sensor as it needs to be cleaned every 6 months from dust build up . Use a q tip and contact spray.