Hi guys,

I noticed the other day that the rear AC system on my 2003 UL LS430 is not working properly and is presenting an unusual behavior.

- The two vents located behind the passenger seat do not blow cold air when AC and LO or HIGH is on.
- However, the fridge does get cold air on those modes.
- When I turn off rear AC button (ie green led is off) and keep green led ON under LO button, I do get a cold breeze coming out only from the left rear vent behind the left head rest, but no cold air in the fridge.

So it seems air blowing cold in some modes but not in others. I would assume AC pipes are working ok, but something else is preventing a normal working condition in all modes.

Does anyone has had this problem or has a hunch what the problem might be?
thanks in advance!

 

Did you set the AC temperature from the back seat controls? Remember that it is a 4 zone AC system with separate controls for all 4 seats.
If the fridge is working then the rear cooling circuit is working but the rear heat exchanges for the vents could be clogged or the vents themselves may be not opening.

 

Hey bigboomer,

Thank you for replying.
I tested it out today controlling the rear AC from the back controls. The problem is the same:
- In LO mode, the rear left vent works, but the right does not. Fridge does not work. Everything is totally silent
- In AC LO, none of the rear vents work, but fridge does work. Weird noise comes from the right rear vent (sound file attached)
- In AC HI, none of the rear vents work, but fridge does work. Weird noise comes from the right rear vent.

It seems weird that the left vent opens in one mode, but not in the others. Should I take it to the dealership?

 

If there isn't even a warm wind coming out of the rear vents I would suspect a blocked/damaged blower motor.
https://lexus-europe.epc-data.com/ls...color=8P8&trim

 

Thank you so much BigBoomer! I will take it to the dealership to get a quote. Do you know if 1 blower motor serves the 2 vents of if each vent has its own?
Any clue about the weird noise in the attached file?

 

I've not had it apart but from the diagrams there is only 1 blower for the rear and 1 for the front.
I think that the noise is the blower, either jammed or else broken.