Blinking Ac Switch Fix And No Cold Air

[gbhrps]

Gentlemen,

Since the day of purchase, my wife's 2004 ES330 has had flawless Automatic AC, until today. At startup the entire system worked fine, except that there was no cold air from the vents, and the AC button was flashing slowly.

A quick check of the 2 on board fuses marked AC showed that both were good. Under the hood the serpentine belt was fine, and all other systems were good.

A search online to another Lexus forum for similar symptoms gave the solution. On the 2004 ES330 and the previous 3 year ES300's all share the same fault. The Magnetic Clutch Relay goes bad and doesn't allow the AC compressor to be engaged and spun by the serpentine belt.

Lexus knew of the problem years ago, and updated the MAG C Relay to an updated one that is improved in a TSB.

Find the large relay under the hood in the fuse box labelled MAG C. It has a long part number that ends with the digit 2. Go to any parts store and ask for a cross reference to the updated part that ends with exactly the same numbers as the original, BUT with the last digit of 8 instead.

Here in Canada I paid $30 for it. Stateside should be in the $15 range. Beware, that Lexus dealers want substantially more!

Pop the new relay in, and unless you have a bad compressor, low refridgerant, or other malfunctions, your flashing AC Light should be gone, and the cold air should have returned. Good Luck!

[John Borrowman]

gbhrps is a life saver! My mechanics have been tracking this problem for 6 months. Nothing would show up in a diagnostic check. They even re-set all computer settings to factory original. They and I were going nuts. I printed out this post, took it to them and voila - fixed!

[1990LS400]

Attached is the TSIB about this issue.

t-s-i-b-el009-05-02-04-es-300-330-03-04-gx-470-a-c-light-flashing-magnetic-clutch-relay.pdf

[Jordan Cohen]

I have a 2005 es330, my a/c light is blinking. I replaced the mag clutch relay but it did not help. Any other idea's. I replaced the compressor last year.