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2013 Chevrolet Suburban
Platform: GMT 400, 800, 900

2021 suburban air suspension issue!

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Old Mar 14, 2026 | 4:23 PM
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Default 2021 suburban air suspension issue!

Afternoon all,

I have a 2021 Suburban HC which of course finally threw the code fix suspension leveling system or something to that effect. Its funny, I've owned 2 suburbans and one tahoe with air ride suspension and every one of them has failed after about 5-7 years. Love the vehicle so we deal with it. I have a hobby of restoring old cars so i'm pretty handy so i like to try fixing these things myself when i can. I hooked it up to my .innova code reader which reads suspension codes and it is throwing a C-118B-00 code which is a left front air spring pressure low code, so I sprayed the soapy water all over the spring but got no bubbles, which is when i realized the compressor is not even running. So I lowered the rear spare and confirmed that in fact the compressor isn't running. So before blowing 3-400$ on a new compressor I checked the voltage going into the compressor, and on startup or hitting the start button i am getting voltage to the compressor but only 8.1-8.3V. So I have a voltage problem. I even alligator clipped the compressor to a small 12V battery and it fired right up on that. I'm wondering if it is a bad relay or fuse, or corrosion somewhere but the wires that feed the pump, but off the pump they go right into a large wire bundle and head forward toward the cab/hood area so i can't imagine there is corrosion in there it is pretty well sealed.

My biggest question to anyone on here is where in the world is the relay or fuse for the air compressor! I have searched far and wide, all 3 of the fuse boxes, and gone from one end of the internet to the next and cannot for the life of me find those fuses or relay or ACCURATE information on where they are. All i can find is info on the model of suburban prior to 2021 - but that doesn't cross over at all. Also, maybe the there is corrosion on the air suspension control module but i can't seem to find that either.

Thanks for any info you might have!
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Old Mar 17, 2026 | 8:52 AM
  #2  
Cusser's Avatar
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Originally Posted by kconnor123
Afternoon all,
Its funny, I've owned 2 suburbans and one tahoe with air ride suspension and every one of them has failed after about 5-7 years.
Not "funny" or strange. There is a business plan these days to get products to last just through the warranty.

Ask me why our 1994, 2005, and 2014 Suburbans all had the same in-dash vent actuator go bad !!!!

Why did Nissan wait until 2010 to fix their problem of radiators leaking internally (ruining both engine and transmission) of 2005-2010 Frontiers and Xterras with V6 engines and automatic transmissions??? One day or 1 mile over warranty and one would be screwed !!!
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