Hello, I'm new here and have a couple of questions if you don't mind

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sjphi26

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Hi guys, my first post here. Reddit has been helpful on previous issues, but google has often led me here when researching other repairs.

2003 Yukon XL 6.0 Denali.

Has about 175k miles (original owners didn't drive it daily) and I've had it about 4 years. It did have to have the transmission rebuilt at the beginning of 2023 but the engine seems solid. From everything I've read, the engines are considered very reliable so I plan on keeping this thing running as long as I can.

But there have been quite a few issues everywhere, mostly due to age and wear, which is to be expected so it's nothing that alarms me. It's also been a fantastic learning experience for me, as I've done some repairs that I wouldn't have thought myself capable of 5 years ago. Full front end including idler and pitman arms.. converted air ride to standard shocks, replaced leaking hydroboost, power window control unit, window regulator/motor, rear pads and rotors, and some other things I can't remember.

My next project is the instrument cluster... all of the gauges are toast. I have the rebuild kit with new stepper motors, and will tackle that this weekend. But while I'm dealing with those electronics, I also want to ask about the "passenger airbag" light on the powered rear view mirror. It's constantly flashing off and on. If it's purely cosmetic, i don't mind, but if it's indicative of another issue, I want to resolve it. Could that be a bad ground somewhere in the engine bay? Is it a solder joint that I can fix? Is it a sign of some other underlying electrical problem? Or just a bad mirror? So that's my first question.

Second question is about AC. It's been out for a while, but now that summer is approaching in TX, i need to get this fixed. The compressor wasn't running, so I jumped it with a paperclip at the relay for testing purposes, and immediately heard what has to be a leak, a very loud leak. I believe it's at one of the service ports, but it's hard to tell, i can't really feel where it's coming from... but I've ordered a kit to replace both high and low. I'm also replacing the accumulator, the pressure switch on the accumulator, and the orifice tube. I've ordered a vacuum pump and manifold. I think i've watched enough youtube videos to where i feel confident about doing it this weekend, but are there any other parts I should replace that may have been damaged by air or moisture in the lines? The AC hasn't been running for quite some time so I don't know what kind of shape everything is in. I'm not a rich man, so I don't want to throw unnecessary parts at this, but I also don't want to take the chance of not doing it correctly and ruining more AC components later down the line.

Thanks for reading. Any other things I should look at that go bad around this time for these vehicles? Any engine stuff I should do as preventive maintenance? I don't have any codes at the moment.
 

Donal

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The air conditioning system probably be the bear. If you pull a vacuum on the system and have leaks, air, hot humid air is pulled into the system and new accumulator will soak all the water out of the air. The result can be that the new accumulator has lost some capacity. After you have replaced all the AC components, purge and pressureize the system with nitrogen gas or what ever pure dry gas you can obtain. Do not run the compressor. You can monitor the system pressure on your gauge and see if you have a leak. I f you have a small leak and cannot hear or find the leak with spray on soap water, the compressor seal is probably the leak source.
You can confirm the compressor leak by unbolting the compressor, but leave the hoses connected. Obtain a large plastic trash bag or such and slip the bag over the compressor. Seal the bag around the hoses and what ever else you have to include. Remove all the air from the bag and pressurize the AC system. If the compressor seal is leaking the bag will indicate it by filling up. Br sure to add new oil to the AC system.
 

bill1013

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Aloha and Welcome to the Forum. When it comes to the AC you may want to take it a professional as they will have the parts and tools ( ex:vacuum pumps and compressors) to bring it back to life. Seeing how it’s been idle for so long it may only need new seals and other synthetic parts. They can give you an estimate as to what it will cost and the parts it requires to get it working again. Hope this helps.
 

Joseph Garcia

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Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.
 

swathdiver

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The airbag light has to do with the sensor in your passenger seat. Or maybe someone is sitting in it and fidgeting around setting it on and off like a small adult or a big dog.

Get a sniffer and a scale to weigh the refrigerant. Use the sniffer to check for more leaks once there is freon in the system. Look under the RR tire, condenser up front, AC lines, etc. Too little R134 is not good, too much R134 is not good. Four 12 ounce cans ought to be just right for a Yukon XL with rear air but double check.
 
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sjphi26

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The air conditioning system probably be the bear. If you pull a vacuum on the system and have leaks, air, hot humid air is pulled into the system and new accumulator will soak all the water out of the air. The result can be that the new accumulator has lost some capacity. After you have replaced all the AC components, purge and pressureize the system with nitrogen gas or what ever pure dry gas you can obtain. Do not run the compressor. You can monitor the system pressure on your gauge and see if you have a leak. I f you have a small leak and cannot hear or find the leak with spray on soap water, the compressor seal is probably the leak source.
You can confirm the compressor leak by unbolting the compressor, but leave the hoses connected. Obtain a large plastic trash bag or such and slip the bag over the compressor. Seal the bag around the hoses and what ever else you have to include. Remove all the air from the bag and pressurize the AC system. If the compressor seal is leaking the bag will indicate it by filling up. Br sure to add new oil to the AC system.
Thanks for your response. So, in theory I could replace the high and low ports (which is where I THINK the leak is coming from) and then pull a vacuum, before replacing the accumulator, to check for any other leaks? And if it holds the vacuum, then I can replace accumulator and pressure switch, vacuum again, then charge with refrigerant? Does this seem right?

And then, if there are still leaks after replacing the service ports, I can continue troubleshooting from there, and keep the accumulator in the box until I find the leak.
 

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