GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello my name is***** am an ASE Master Technician and I am glad to help you with your question.
You need a scan tool, you will have codes in the air ride system that is causing the light on the dash to come on.
The most common cause for this problem is a faulty air compressor. It is located on the drivers side behind the rear wheel. This could also be a level sensor issue. There is a fuse under the hood to check, it should be labeled air compressor. You will need to check for voltage at the compressor. I can send you the factory diagram for this circuit if you would like.