1999 Lexus ES 300, Cooling Fans Stay On

This 1999 Lexus came in with the complaint that the engine cooling fans would stay on even after the key was turned off. The customer stated that they stayed on for an hour or more and she had to disconnect the battery to keep it from going dead. I figure that there was a relay sticking so I took a quick look at a component locator and found that there were several relays listed for the cooling fans. I pulled each one that was listed and no single relay would turn both fans off.

I decided to look at the wiring diagrams and honestly they wire quite confusing because there was actually no way according to just the cooling fan diagrams that the fans could turn off. I dug a little deeper in the diagrams to find out how the listed cooling fan relays were supplied power and ground. In the power distribution diagrams I found that there was an engine main relay listed that had to be the problem. I am pointing to it in the picture below.

I removed the relay and both cooling fans stopped at the same time. I also noticed a slight bit of soot on the white plastic.

I removed the cover from the relay and sure enough the contacts were stuck together and there was a lot of soot.


I tried to break the circuit by applying pressure to the hinge spring but that did not work.

I then used my pocket screwdriver to separate the contacts. I also use the tip of the screwdriver blade to clean the debris from the contact. This enabled the car to be driven again until I could order a new relay from Lexus.

Just a picture of the soot inside the relay cover.

I inserted my pocket screwdriver blade as shown below to release the retaining clips for the cover and repeated on the other side.

A picture of the relay with the cover successfully removed.

This picture show the part numbers on the relay. 85925-17010 and 056700-7770, one number is a Toyota part number and the other is a Denso part number.

9 discussions on “1999 Lexus ES 300, Cooling Fans Stay On”

  1. ES300 2001 is the model and year. The problem was that two fans located right behind the radiator kept running and drained the battery, even the engine was turned off and the key was taken out.

    I replaced the relay as Sparky had identified and the problem was fixed. Thank you so much so much. Wanna share one more thing, a new relay at the dealer costs $62.
    Thanks again, Sparky.

  2. This just verified what I had found myself. First thing I found was that when at an idle my AC would not cool. I found that the fans were not working. On a long trip my vcs and check engine lights came on and then after stopping at a light when I got going my transmission would not shift into overdrive. So one evening I opened my hood and I touched the top of the relay cover and the fans started. So I opened the box and wiggled the relay and the fan started again, but this time it would not turn off, I pulled the relay out and the fans stopped..I replaced the relay and all is well…is was told that the deal with the shifting tells the operator that there is a malfunction…last time this happened it was my oxygen sensors… I love my 1999 Lexus ES 300

  3. My wife and I got stranded 400 miles from home in a motel on a road trip. The fan did not turn off and over night killed the battery. I followed your instructions and was able to fix the problem and complete our vacation trip. The fix is temporary: 10 days later the problem came back, but back at home I had a new relay installed. Thanks a lot.

  4. My dad’s ES300’s cooling fans would be on when the car was off and the fans would go off when the ignition was turned on. Fortunately, I found this webpage. Unsticking (it was arced together) the relay you pictured solved the problem!
    Gotta go… I’m off to the Toyota dealer for another relay…
    Thanks Sparky!!!

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