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

[mike singleton]

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.

Congrats on being brave enough to replace the stepper motors on the instrument cluster. I had great results with just letting Circuit Medic rebuild mine (shipped it out) and replaced the lamps with blue leds. (more modern appearance). That 6.0 engine is rock solid - Enjoy.

 

[mike singleton]

Congrats on being brave enough to replace the stepper motors on the instrument cluster. I had great results with just letting Circuit Medic rebuild mine (shipped it out) and replaced the lamps with blue leds. (more modern appearance). That 6.0 engine is rock solid - Enjoy.

https://circuitboardmedics.com/

 

[nonickatall]

I do air conditioning service in Germany and know my way around quite well.

The problem at the top connections may be the Schrader valve. These Schrader valves are simply screwed in and can be replaced.

You don't have to replace any lines. It's rather unusual for the lines to leak, except for the line that goes from the front to the rear air conditioning system, which lies under the body of the vehicle and is exposed to salt and other things. it can go defect sometimes.

Otherwise it makes sense to go to a workshop that has an air conditioning service device. Because it is important that you first pull a vacuum, and you should pull the vacuum for at least 60 minutes, if the air conditioning system has been open for a long time.

Pulling a vacuum means, that the vacuum pump runs during this time and the water that evaporates due to the low pressure is drawn out of the system. Because the system must definitely be free of moisture, otherwise this moisture will form ice crystals on the expansion valve, which then leads to this: Your system runs briefly until it gets cold and then no longer. From my perspective you don't need to replace the dryer cartridge, when you hold the vacuum long enough.

Afterwards you usually hold the vacuum for another 20 minutes, which means, the vacuum pump is off and you check whether the vacuum is maintained.

If the vacuum is maintained, this is the first indication that the system is tight.

To check if the system is tight, we do this in Germany by filling in compressor oil that contains a contrast agent. And of course the right amount of refrigerant.

If you leave your air conditioning running, you can use a UV lamp to see if there are any leaks.