A/C issue, how to replace the 50a fuse?

Tiny
DIVIDES
  • MEMBER
  • 2009 LEXUS ES 350
  • V6
  • AUTOMATIC
  • 130,000 MILES
Friend if mine's car. His A/C was not cold and fan not running when I checked. Lexus said that the 50a fuse is blown and needs to be replaced and that the fuse box needs to be disassembled to do that. I want to change it for him. Any instructions on how? They are asking too much for labor. They said no power going to magnetic clutch relay or the fans.
Sunday, August 15th, 2021 AT 8:01 PM

11 Replies

Tiny
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  • MECHANIC
  • 6,383 POSTS
Hello,

That fuse is located in the fuse box under the hood. That fuse box is located close to the driver side fender (see diagrams).
The fuse number is 34 (50A).
You will have to remove the plastic covers for the engine to get to the fuse box.
After that you simply take off the cover the replace the fuse. You do want to make sure that the fuse is indeed faulty.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://youtu.be/ZBtpZx7BSzc

Please let me know of any questions.

Thank you.
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Sunday, August 15th, 2021 AT 11:05 PM
Tiny
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Fuse was faulty, after I installed the new one I saw some smoke coming out of the fuse box especially around the relays. Removed the negative immediately, there is some blemish around the new fuse as well, right in the middle, switched couple of relays, turned it on all okay, started, fan works, air is good. I don't know what they did when they fixed the car after the accident, something in my gut tells me something isn't right.
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Friday, August 20th, 2021 AT 6:40 PM
Tiny
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It could be for a wire being pinched or exposed or shorted. It will be difficult to know which one without tracing the wiring harness for the A/C system. Might even have to dig even deeper with other harnesses. As many of these components are connected and can impact one another.
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Friday, August 20th, 2021 AT 7:00 PM
Tiny
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Ya, am aware, I let them know. I told them to sell it, they can be having more issues in the future.
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Friday, August 20th, 2021 AT 7:04 PM
Tiny
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That's right having an electric gremlin can be very challenging.
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Friday, August 20th, 2021 AT 9:18 PM
Tiny
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Car is not working this morning, strange. Jumped it and went for a rode all good. Alternator charging 13.7v. Came back from a 5 mile drive, parked it. Turned it off and started twice no problem, left it for 30 minutes came back and its totally not working. Battery.82v, what the heck. How is that possible? This is the fuse cover. Anything you suspect that causes that?
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Saturday, August 21st, 2021 AT 10:48 AM
Tiny
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Also just kept it running and looking at scanner voltage is 13.1.
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Saturday, August 21st, 2021 AT 11:12 AM
Tiny
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After running for a while still at 13.2. Turned it off and kept voltmeter connected to battery. Watched it drop slowly. In 2 minutes dropped from 12.2 to 11.90.
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Saturday, August 21st, 2021 AT 11:23 AM
Tiny
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It appears that the vehicle has an excessive amount of parasitic draw.
A parasitic draw (current drain), can be caused by a number of electrical equipment. It could be as simple as a glove box or a trunk light staying on. It can also happen for a short in a electrical circuit like a window switch etc.

Check out these videos for some helpful guide:

https://youtu.be/z5F7WpgjaRs
https://www.2carpros.com/articles/car-battery-dead-overnight
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Saturday, August 21st, 2021 AT 11:35 AM
Tiny
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Ya, I checked all the lights and none are on. I doubt it is a light because the drain is quick. It may be a short due to the smoke that I saw when I installed the ac fuse. One thing after another with this car.
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Saturday, August 21st, 2021 AT 11:53 AM
Tiny
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It does sound like a short. Try removing that 50A fuse and see if the current drain still exists. It could the harness for that fuse.
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Saturday, August 21st, 2021 AT 3:02 PM

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