Review on 🚗 Dorman Air Suspension Compressor 949-099 for Cadillac, Chevrolet, GMC - OE FIX by Brant Skogen

I just installed my new Dorman air suspension compressor on my 2005 Chevy Tahoe. I was very happy to see that the Service Ride Control message didn't appear when I started the truck. I was a bit concerned after initially not hearing the compressor. Normally my old original 120k mile supercharger was very audible. I quickly turned off the radio and heard the faint hum of the compressor. I parked the truck and went to the back of the truck to check the pressure on the air shock bellows and definitely felt it was pressurized unlike before. So I jumped back in the truck and started it again. With the windows down and the radio off, I could hear the supercharger kicking in as usual, then shutting off after a few seconds. I'm really impressed with how quiet the new compressor is. This day and night is different from my original device. If I had to decide on a new unit, I would wish that the wiring harness was a little better protected. The main part of the harness, where the wires enter the back of the main connector, had quite a bit of exposed insulated wires. I added some of my sanding tape as the wiring harness is next to the frame when the compressor is installed. It's really the only thing I noticed. Everything else was there. Installation was very easy. The hardest part, and not hard at all, was separating the stock air intake filter from the plastic push pin next to the fuel tank injector inlet. Also make sure that the positive battery terminal is disconnected. Then start by unplugging the main harness connector, which is on top of the supercharger, directly opposite the frame. Then disconnect the air line by removing the retaining clip. Now simply loosen the 2 exposed 13mm bolts closest to the rear body mount, then loosen the 1 13mm bolt located inside the frame about 8-10" above the first two. You will need a deep 13mm socket for this. Nuts do not have to be removed completely. Just loosen them a bit and then tap the 2 protruding nuts with a hammer to loosen them from the frame. Push on the compressor housing and you will see the bolts/nuts go into some of the slots in the frame. With everything disconnected you should be able to lift the compressor about an inch and move it away from the frame. Simply follow the steps in reverse order to install a new unit. I would also suggest that you take an air compressor and blow out any debris that may have gotten into the harness connector and maybe add some dielectric grease to the connector to keep moisture out. This is also a good time to inspect the air damper bellows along with the air lines for cracks or breaks. If you are losing air and making the compressor work too hard, change the compressor sooner than you would like. As for my specific problem, it was a common error C0660. Which indicates a malfunction or short circuit in the level control outlet valve. I haven't found any noticeable wiring issues on the outside of the exhaust valve. So my guess is that the wiring in the exhaust valve is rusted and/or broken like so many others. I did a basic check of the fuses on the side of the dash and under the hood. I also checked the ALC relay which is located at the bottom of the under hood fuse box where one of the main wire harnesses enters the fuse box. All of this is well tested. I also connected power to the ALC harness connector 30 through 87 and was able to turn the compressor on manually. After running these basic checks, I knew it was time to call in a professional OBD-II scanner to see what the real problem was. Good luck to anyone having autoride suspension issues. Before you start replacing parts, take your time and diagnose as much as you can. If you are inexperienced with, or don't have access to, a professional OBD-II scanner, find a recommended mechanic and have them get the codes and check all of the data from the sensors. Even if you have to pay for hourly work, it's not worth spending money on a potentially easy fix.