Hi all.
Rarely paid attention to it as my trailer is light enough to handle by muscle. But today I hauled a ton+
What is it supposed to do ?
Lift the rear end ?
Lower the rear end ?
Does the engine needs to be running to operate ?
If vehicle is not level, is its operation disabled ? I get three 'dings' at the button push.
There is only one 'height' button. (upwards?)
After raising, how do you later return to wherever it was before or how do you lower as to disengage a trailer ball ?

If you raise the rear+trailer; support the trailer tongue; how do you lower the vehicle to drive away ?

 

The elevated rear height is only for low-speed manoeuvres, for ground clearance. Once you go over 15 mph (I think) it will resume normal ride height.
Supposedly, if you have a lot of weight on the trailer hitch then the system will self-adjust to the correct (non-elevated) ride height.

The key certainly has to be on for the system to operate. Maybe it also has to have the engine running -- I don't recall exactly. I do know that it would only work for me after I had been driving for a hundred feet or so. Until then it would give the dings that you describe.

 

Mollusc is correct - for towing, the main functionality of the SLS system is to keep the rear at the normal ride height, despite increased weight. The off-road suspension setting on the dash is just for low-speed driving and will disable on its own at higher speeds. Otherwise, to go from off-road height to normal height, you can just push the button again and it should lower itself. The truck needs to be running for the air springs to adjust, and it will only do so if all doors are closed.

For towing purposes, there was original SLS functionality that would allow you to *lower* the rear suspension in order to connect a trailer. This required a separate key fob. If you don't currently have a separate key fob that works with this functionality now, then I'd imagine it would be prohibitively expensive to add.

Realistically, I'd just pretend it doesn't exist when towing, rather than trying to mess with it to raise and lower to help with your trailer. The benefit over normal springs will be the correct ride height even with the trailer attached.

 

Thanks, fellows
Then I just created myself another project. As I never go rock climbing; and often pull a trailer, modify the contraption with a manual up/down switch to deflate (purge) and raise (inflate) the suspension bags will be of much better convenience.
Will study the schematic to see how to disable the current 'feature' and make it my way instead.

 

I doubt that you'll be able to do that. It's a momentary switch. The SLABS unit decides what state to put it in.

 

Sure you can rewire the rear suspension to do what you want, but the key is getting the position sensors to work with your system. Depending on your skills, you could program and arduino/similar mircroprocessor to set the limits, and that would work out nicely with a dash switch......

 

Thanks. A multi-contact switch can disable the stock SLABS and height sensors configuration and another switch or sets of contacts toggle up-off-down by pumping or venting... Will give it some effort, I have no problem with electronics.