Please help. I parked our 2006 SC at my parents house for a few days while we went on a trip. idk why I decided to put it in access mode and park on their driveway which is very steep. something in my mind about it being 15F and didnt want bags extended. When we got back, it was down on the front stops. I turned on car but it did not pump up. I pulled it to level surface and tried to drive a little but nothing changed other than leveling out. I am also not hearing the pump come on.

We have had this truck for over 5 years and 100k miles. The only air suspension issue ever was the front bags which I replaced a few years ago. Right now there are no suspension lights or errors. It does not respond to the selector to change ride heights.

A few things to note....I have oversized tires, so its pretty bad trying to drive to get over speed limit to make it raise. I havent tried to turn lock to lock but not sure if tires are too big to do. Additionally, it has lifting rods after we put the tires on. I was wondering if leaving it in access height which made it quicker to hit the stops has somehow put the height sensors out of range for it to read now.

Any suggestions on what I should try? I'm about 200miles from home but have access to all sorts of tools with which to try and manually energize pump etc. I would assume trying to do the suspension reset by turning lock to lock is what I will try first. But other than that, is there any thoughts on what I should try? Air suspension has always been rock solid over the years and other than running a little more often after the lifting rods and a noisy muffler thing its been fine.

The only indicators I get are some flashing alternating red and white lights over the corners on the center screen.

Any help or suggestions would be greatly appreciated. Cheers!

idk why but pics of center screen arent showing. basically its just he image of the suspension and theres little lights that alternate red to white above the 4 corners

subtle bump.... can anyone point to a schematic or diagram of the air suspension wiring? I'm looking for pinouts of air compressor and/or valve block. Right now my only thought is to try and hot wire compressor pump on and see if I can manually raise it in hopes that height sensor will be in a range that it can read...assuming that is contributing to my issue of no response from system and compressor not kicking on. thanks!

Check the compressor high current fuse as a first step, it may well be that the compressor has some ice formed inside it and has taken the fuse out when it tried to start. I'll post a circuit diagram later when I have access to my PC.

thank you thank you!!! thats what I was hoping there would be a fuse to check as well. a diagram would be greatly appreciated!!!

IIRC the fuse is in the rear fuse box, if you drop down the cover, there should be a schematic of the fuse and relay allocation.

One of the ideas I got from my local mechanic is to disconnect one end of the height sensor and manually push it into range and see if that allows the compressor to kick on. I guess I would need to do that on the front and the back at the same time. this would be in leau of using jacks and jack stands to raise it manually.

If the 'extents' icons are flashing above the wheels on the 4x4i screen, the system already knows it needs air... Until you've exhausted electrical checks, I wouldn't advise pushing or pulling the height sensors, you may well create a secondary fault.

okay thanks! yes I believe the "extents" icon is the ones that are fashing red and white. I'll proceed to check electrical to pump first.

Hi, have you tried a battery disconnect procedure? Have a look in the Wiki section for the procedure. It might reset any faults and is worth a try.

Hi. Thanks for the suggestion. I did disconnect the battery and touch terminals to try and drain phantom power. however, I only let it disconnected for about 3 minutes. I can try to do it for longer period and see if that changes anything. thanks!

Electronic Air Suspension wiring diagram below - hope it helps.
As I advised previously, check the relevant fuses first before getting too deep, if the compressor fuse is OK, then check with a voltmeter that you have 12V across the compressor plug, if not, then it's possible it could be a failed relay (also in the rear fuse box), given you're getting height data on the 4x4i screen, it's unlikely that the control module or the height sensors are defective, from this side of the pond it seems like a more fundamental problem - i.e. the compressor cannot provide compressed air -or- the airlines / valve blocks / filter-drier are frozen or otherwise preventing free passage of air.

https://www.fullfatrr.com/gallery/albums/u...ension.pdf

thank you so much!!! I'll give that a read and a shot! cheers!

Hi Phoenix. the electrical schematic is great. Is there one for the piping of the air so I can better understand how it all operates? Thanks!

Here's a few screen grabs, you can download the full workshop manual from here https://www.fullfatrr.com/wiki/Main_Page which has far more info.