Lexus Rx 330 - A/c Not Working

[carlover_rx]

hi all,

i have a 2003 Toyota Harrier 300G. its a Japanese import. ( Similar to Lexus RX 330 / 350 in US ). The display screen on the dash which houses A/C, TV and GPS also.

Currently it has done 110,000km

Few days ago i noticed this A/C issue.

Suddenly a/c stopped working. it was not cooling at all.

When i opened the bonnet, i noticed that a/c compressor was not working, and even the 2 cooling fans behind the radiator was not working. At that point i noticed that temp gauge was moving towards RED zone. so i immediately stopped the engine and kept for a while to cool down.

After 30mins when i started the engine every this was fine back to normal. i was amazed.

A/c comp clutch & 2 fans back to normal.

Everything went ok for 2 days. however today suddenly it happened again.

Now both cooling fans are not working

i checked below.

1. Radiator coolant - almost full both inside the radiator & reservoir.

2. A/C diagnostic codes : shows "00" ( http://www.lexls.com/tutorials/air/accodes.html )

can someone help me on what else to check?

is this due to low air pressure ? or any other A/C ECU fault ?

or any other connector loose connection or faulty radiator fan ?

im so worried about this.

Is there any A/C repair manual ? ( since both harrier & lexus same can refer to a lexus Rx 330/ 350)

[carlover_rx]

hi,

Finally managed to sort this out.

Hope this may help you guys too.

Setp by step diagnosis:

-----------------------------

1) i removed the power out sockets ( there are two connecters for two fan motors. refer pic attached) from the fan controller unit and checked the voltage using a voltage meter. Power is there when i switch on the A/C.

- > Meaning no electrical issue upto the fan controller output.

2) Then using a flexible wire i directly gave power to fan motors from the battery.

a. Left side one started immediately. - meaning no issue

b. Right side not started immediately. when i tap the fan motor with a screw driver it started to

rotate. seems there is a brush contact issue inside the motor.

- > Meaning i had to replace the faulty fan motor ( since motor is sealed type, cant repair )

3) Reason why both fans were not working was b'cos, two motors are powered in "series mode" from the fan controller. Thus if one is not working, other will also not work. :-(

4) If the cooling system is not wirking well and not maintaining the temp, ECU will automatically shutoff A/C system to avoid any further damages to the engine & radiator.

-> Thats why a/c went off.

5) I managed to find a used fan mortor from a recon-parts shop for USD 70.

Now everything back to normal.

Note: please check whether fans get triggered for both A/C as well as radiator temp.

- To test this 1st switch off a/c and let the enegine to run for a while. Make sure you have enough radiator coolent. At a certain temp radiator colling system will trigger the fans. if this is ok that means radiator cooling system thru radiator temp trigger is woking normal.

- Next switch on A/c and set below;

i) Temp = MAx cold

ii) Air recurculation mode = internal circulation ,

iii) Blower speed = Low.

Let the A/c runs for a while. at a certain point A/C compressure will cut off. at the same time fans will also switch off. If htis is happeneing then that means radiator cooling thru A/c system trigger is working normal.

hope this will help you guys.

Cheers

[Lexilover64]

THANKS!

[Lexilover64]

You have described my problem perfectly. I almost replaced the compressor. Thought it was strange that the fan nearest to the compressor would cycle off and on. The a/c clutch would engage as the fan engaged. Yes tapping on fan prompted it to operate. Works intermittently. Will replace fan ASAP! I live in Texas and use the A/C 11 months a year.

[Boxbrownie]

Excellent diagnostic work leading to a correct solution, for others here I think this ought to be in the "how to" section as a sticky.

[Lexilover64]

Never replaced the fan, Instead I replaced the relay $22. no problems since. Thanks!

[lsrxlex]

My 1999 rx300 just got 2 servo motors replaced by Lexus because of intermittent noise behind the radio. Since then the AC doesn't work right intermittently.

One time I started the car with outdoor temperature 86, the AC gave hot air, really hot. I turned it off and restarted after 15 minutes but still hot air. Half hour later when outdoor temperature was 77, then it worked Ok for 20 minutes then gave very hot air again. If I used fan only, manually, no recirculation, then it worked fine giving me outside fresh air.

Today I connected 12v directly to fans and they worked fine.

What would be the cause.

Thanks.