I've hunted the web looking for my issue, and the answer may be here, but I've not found it..my truck was parked for a month and when I went to pick it up, the suspension was all the way down..I've never had a issue before so I started it up and drove home. Now I've checked every fuse that mentioned anything about air suspension, all good. I read check the relay. Mine isn't behind the bumper, so I found it located on the compressor bracket. I pulled the relay ( not knowing if it was bad or not) and jumped the wires at the relay port, the compressor came on. So I let the compressor run and the back has gone up, but not the front. So I started looking for leaks to see if that was the reason the front wouldn't rise. The t in the line was leaking, so I replaced it. The y was also leaking so I replaced the o-rings, and looked for other leaks. I sprayed the bags and everything I could see with soap water and found nothing. The front bags do get hard while the compressor is running. I removed the wheels and put the front spindles on ramps to keep weight on the suspension so I could look at everything. So I ride up to car quest and grabbed a new relay. Nothing. I still have check suspension on the dash, I can still jump the relay port and the compressor will still run but when its together it won't turn on on its own. I've turned the switch on and off , unhooked the battery, like I said, the bags get hard but won't lift the truck, but the rear is still up..please help, its gotta get me back to work.. thanks in advance

 

Look past the top of the driver's front tire. You should see the ride height sensor there connected to the upper A-frame. Are both ends of the sensor connected?

 

Thanks alloro. That put me in the right area..I pulled the wheel and checked the leveler. I unplugged it and cleaned the contacts. Used my jack to work the mech a few times and tried again. It started right up and raised the the pass side instantly. Now I just need to run down a new canister for my compressor cause the little locking tabs that hold it into the pump sheered off. For now I put an extra o-ring on it and the screw that holds it still to the pump is holding it there. That's not gonna last long, but it has me rolling. Thanks again