Peacebay

This is a strange one. Now I know why I thought that the cooled seats used the AC system in the car — because my clutch is always spinning.. I decided to double check after that post yesterday and sure enough, my clutch spun even with the AC turned off. When it’s on, the air conditioning works beautifully and it’s ice cold. Fans cycle on immediately upon pressing AC button, but stay off otherwise.

Any ideas?

Ricklin

I would next confirm whether or not it's 'being told to' IE: check if the clutch is powered up constantly.
I would suspect the relay first if it is always powered. In many cases you can swap relays with another for testing purposes.
Most of the time relays fail they fail in the open position. Note I said most. Occasionally a relay will stay closed when it fails.
My 4runner had an A/C failure, dealer diagnostics said bad compressor, 1,200 dollars please. I said no thanks. I am embarrassed to admit it was several years. I was researching another issue and came on a post @ 4runner.org that mentioned the relay. Sure enough, the relay was bad. I swapped it for the relay for the fog lights, and all fixed. The relay is 20 bucks and is literally 'plug and play' to replace. I'd look at the relay first.

Peacebay

That would be great however I was under the impression that the 04-06 430s didn’t have a relay and that the clutch was told to switch on by the PCM? Can anyone verify this?

Ricklin

Yup, you are right, the entire junction box must be replaced if it's getting the proper signal from the PCM. I shall retract and keep this in mind for the future.
From my limited research it looks like you will need a cable and Techstream to figure it out. There are a number of conditions that must be correct for the PCM to supply the signal to turn on the A/C compressor.

Have you checked that the clutch is powered up when the compressor is engaged? Please update as you sort this out.

Peacebay

It’s strange, because there is a definite difference between, say if I put the climate control at max cool with the AC on vs. with the AC off so while it looks like the clutch is always spinning mechanically the car must differentiate electronically somehow. The air conditioning itself isn’t always on (only when I want it to be), but the clutch is always spinning, in other words.

bradland

Just tossing out ideas here but, mechanical failure...? Maybe it's just the clutch failing?

vredniykot

Mine does the same.
There is a noticeable drop in engine tone when its running at idle and AC is turned on.
Maybe it has another internal clutch?

Not going to worry about it until something breaks 😁

Peacebay

Probably. But the AC works so well and seems to turn off when I hit the AC button off.

I guess that makes two of us then! Lol

rkw77080

The 04-06 LS430 A/C compressor always rotate with the drive-belt. A separate solenoid controls the flow of refrigerant into the compressor, which will determine the mechanical load the compressor sees (i.e. drop in engine tone, etc).

Peacebay

Wow! Great news. rkw saves the day again

Peacebay

As an aside, how haven’t more of us hypochondriacs ever noticed this before??

Ricklin

Darned unusual, thanks Lexus Champion.

rkw77080

Here's a little more details on how the LS430 A/C compressor works...