Control knob

I have seen the above control knob in a cab of a bus travelling between Queenstown, New Zealand, and the Remarkables ski area. What does it do?

The bus is pictured on Ski Bus Transport page (top image, with separate but joined cab and saloon); unfortunately I don't have a photo to paste here.

According to the number plate lookup tool its model is a MAN TGM 13.290.

  • As a guess, the angled wheels indicate the front, and the icons show the 'differential' placed for AWD, RWD and FWD. The two symbols at the top seem to indicate off-road and on-road. So the set of three others on each side (which seem to be the same) are perhaps for those two situations, with the top two for 'fully automatic'..? Commented Aug 12, 2023 at 12:35
  • ... so as pictured the 'upright' position would be the normal on-road fully automatic drive distribution, with manual selection to the right. One click to the left would be off-road fully automatic drive distribution, with manual selection further to the left. Commented Aug 12, 2023 at 12:52

1 Answer 1


While this MAN video doesn't go into a complete description for the switch you're talking about, it does give enough information for a different model to give you an answer.

This switch does control the transfer case for on-road (right part of the dial) and off-road (left part of the dial) driving. The different positions of the switch tells the transfer case what interlock you desire. Just as @WeatherVane stated in the comments, the images with the angled tires are the front end. Looking at the images, where you see the bulge is where the interlock happens. The first image with the bulge in the center is where both front and rear wheels are supplied power. The one where the bulge is to the front ensures the interlock provides power to the front of the vehicle. The one to the rear is for rear interlock. The transfers on these vehicles are all-wheel drive (AWD) units, so power is supplied to all four all of the time. The interlock switch ensures power goes to both, front, or rear as needed. If the computer senses the vehicle doesn't need the interlock, say while traveling down the highway, it will automatically disengage it regardless of what position the switch is in. The center two positions would allow for completely automatic, allowing the computer to decide the interlock without driver intervention.

  • I looked at google results for MAN vehicles (and TGM 13.290) but could not see that particular control. The snow bus linked seems to be a truck conversion. Commented Aug 12, 2023 at 17:20
  • @WeatherVane - Yah, I had to do some digging to come up with what I did. Commented Aug 12, 2023 at 17:27

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