moshlub

Recently my AC compressor died, and in the process of trying to save some money, we ordered an aftermarket AC compressor. On my compressor off of my 1990 LS400, there are two wires that come out of it. On the rebuilt compressor, those wires do not exist.

Does anybody know what the wires do? Is it imperative that the new wires exist on the new compressor?

Lextreme

Its activates the ac clutch. just connect them and doesnt matter which wire is which.

moshlub

That's not what I asked though.

jmblimo

iTrader: (1)

My '92 has a single wire connector for the clutch at the front near the pulley, and a 2-wire connector at the rear. My service manual hints at this being a pressure sensor. The sensor is black and mounts in the center of the rear plate.

moshlub

Thank you for the info. Can you tell me what section and page it is in the manual?

jmblimo

iTrader: (1)

Hi, I was mistaken as to the function of that module on the rear of the LS compressor. Upon further study; what it does is measure the revolutions of the compressor. The manual says that if the compressor should not turn like it should, the computer will shut it down and flash the little green light on the dash A/C control panel.

That info is on page AC134 in vol. 2.

moshlub

Thanks for the information.

So upon reviewing the short description on the top of page AC-134, I am led to believe that the sensor is a required item and that my rebuilt AC compressor will not work. The description reads:

On page AC-136, it says the compressor lock sensor should be 530-650 Ohms at 25C (77F) and 670-890 Ohms at 100C (212F). Although I doubt it will work, has anybody used a resistor before to bypass the lock sensor?

moshlub

Update 7-26-05:

Because the rebuilt compressor lacks the compressor lock sensor wires, I called up the parts shop and explained to them that I talked to Lexus. The parts shop says he can overnight a brand new compressor, which is made by Denso (like the one on my Lexus), and it has the wires. None of the AC compressors they sell (no matter which car) come with any sort of sensors like that.

So on 7-25-05, the new compressor arrives. It is EXACTLY like the original one that was on my car. Hopefully no other problems arise.

Lesson learned:
Don't buy rebuilt AC compressors. Bite the bullet and pay for a brand new one to assure fitment requirements.

jmblimo

iTrader: (1)

I bet that is going to be a hit! Will they take the rebuilt unit back? Also, I wonder why the rebuilders don't include the sensors with their units. i would think most folks would simply send in the old compressor with the sensor still on it.

The Lexus dealer wanted $1500 to replace mine ('92 LS400) about six years ago. I ended up getting one from a salvage yard for $300 and doing the job myself. "knock on wood," it is still working fine, very cold.

moshlub

They took the rebuilt unit back, but I had to have the shop say that the new unit was a "warranty replacement". It was the part store manager giving me the advice, so I paid the difference only.

My only guess as to why the rebuilders don't put the sensors on is, there may be other cars out there that uses the same compressor but don't require the sensors. If Lexus is the only brand that uses these compressors, then they would be SOL trying to sell them unless they install sensors on all of them.

The sensor is part of the rear of the compressor. It is part of "disc" per-se that is installed into the rear of the compressor using a lock ring. The sensor looks like it can be merely popped off, but it can't. It's built into the "disc" which is about 4" in diameter.

Costwise, my new compressor was $575 plus tax. The rebuilt was $475 plus tax. These are the repair shop's prices.

I believe Lexus charges $1300 (or somewhere around there) for the part alone. I don't know about fitment, but CarQuest/Napa sells the compressor for $1089, AutoZone at $599.99 for the "factory air" (others are available at higher cost), Kragen for $732. (Just to give you an idea of markup, the repair shop's price for the CarQuest compressor was $649. AutoZone doesn't give discounts to shops, and well my shop doesn't like Kragen.)

All the auto parts stores, including where the shop bought mine, required at least a drier/receiver for a warranty to take effect. CarQuest sells it for $32, AutoZone for $75, and I didn't ask at Kragen.

Napa, AutoZone, and Kragen also requires an expander tube. I don't recall the exact pricing, but IIRC, they are between $30 and $50.