How to Fix Auto-Inflate Air Bags Sensor

We use the Air Lift SmartAIR Self-Leveling System to auto-inflate air bags suspension on our Dodge Ram 2500. Sometime after we drove that really rocky road to American Basin for our  Handies Peak run, we noticed a bit of a rougher ride in the truck. Not until we hitched up and Left Vickers Ranch, did we notice the really rough ride. I then realized the compressor for our auto-inflate air bags was not kicking on.

aie lift compressor fuse

Air Lift Compressor Ignition Powered Fuse Tap

So, I checked the fuse for the Air Lift compressor. Check. Then I checked the SmartAIR sensor attached to a leaf spring. This triggers the compressor to inflate when our trailer weight is put on the bed of the truck. It also sends a signal to deflate when we unhitch. This was clearly the problem.

auto-inflate air bags

Broken Auto-inflate Air Bags Sensor Wiring

Why Self-leveling Air Bags Won’t Inflate

The SmartAIR self-leveling system works with a sensor mounted to the truck chassis. This sends the signals to inflate or deflate as needed, depending upon the load. A magnet is attached to a bracket that mounts to the leaf spring. Put weigh on the truck, and the bed sinks, causing the magnet to rise. Take off the weight, the magnet lowers along the sensor shaft.

The bracket that holds the magnet had bent or loosened on our spring at some point. This is a very strong magnet. The bracket was attracted t the chassis and rubbing up and down next to the SmartAIR sensor. It eventually cut through the sensor wiring. And yeah, that was the cause of that random squeak we were hearing!

SmartAIR Self Leveling Suspension Kit Specs and Reviews

Repair SmartAIR Sensor to Fix Auto-inflate Air Bags

Another reason I love our Air Lift suspension kit is the great customer service the company provides. Air Lift has a lifetime warranty on all their suspension products, and they stand by it. There was that time we popped an air bag, and they sent a replacement. I sent an email with that photo and explained what had happened. Within a few days my replacement sensor kit for our SmartAir auto-inflate air bags system was on the way. As expected, it was a simple enough fix once I had the right parts.

auto-inflate air bags

Remove SmartAir Sensor Mounting Plate

To get our auto-inflate air bags working again, I first disconnected the wiring harness attached to the SmartAIR sensor. Then I removed the screws securing the mounting plate to the truck frame. 

auto-inflate air bags

Remove Sensor from Mount

With the mounting plate removed, you can access the Allen screws holding the sensor in place from from behind. Otherwise, the nuts holding the sensor on will just spin. that’s a minor design flaw if you ask me. I was hoping to remove only the sensor without taking off the whole mounting plate. But I digress…

auto-inflate air bags

Replace Screws in Sensor Mount

With the sensor and its mount disassembled, you want to reinsert the mounting screws. I was not sent replacements for all the nuts and bolts. So it’s a good thing I retained everything while taking it all apart. And yeah, I dropped a nut and spent too much time looking for it. That seems to be the case with all my repairs on the road.

auto-inflate air bags

Attach new Sensor to Mount

When attaching the sensor to the mounting plate, it only goes on one way. And this is important. The tab at the top of the sensor fits in the hole at the top of the mount. This ensures the sensor shaft is in the correct position once mounted. Secure the sensor  to the mounting plate and this job is half done.

auto-inflate air bags

Assemble New Trigger Magnet

Since it was my magnet bracket which cause this problem in the first place, I was sure to ask for a replacement. When I originally inquired about getting the parts, I presumed the kit would include the magnet and bracket too. It didn’t, so I’m glad I asked.

SmartAIR Self Leveling Suspension Kit Specs and Reviews

I compared the markings on my old bracket to determine where the Magnet should be placed on the bracket. I left it loose so I could fine  tune the adjustment once the bracket was mounted.  

auto-inflate air bags

Reattach Sensor and Magnet

With everything assembled, I attached the sensor to the chassis. I then reconnected that wiring harness, Finally I attached the new trigger magnet bracket so it aligned with the sensor.

At first I freaked out! It wasn’t working. With the ignition on, I moved the magnet down. The compressor didn’t kick on. I checked the fuse again, and started to get frustrated. Duh! When weight is put on the bed of the truck, the magnet goes up along the sensor as the bed sinks. Hearing that compressor was a joy, and meant this was another successful mission accomplished. With the truck bed level, and the magnet centered on the sensor, I tightened it onto the bracket.

And now, our LoadLifter 5000 auto-inflate air bags auto inflate like they’re supposed to once again. All thanks to our SmartAIR self-leveling suspension system and the fantastic customer support at Air Lift.

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