Coach, in mid-2019, we implemented a change to the upper sections of the rear arm brushes to help improve wash quality on SUV's with their increased angle of the rear glass. The upper 7 sections are now using 72" length brushes rather than the original 60". This has made a big improvement
I wouldn't recommend increasing the rear arm pressures unless necessary. You want to see about 4-6" of crush so the tip speed of the brush can be maintained. Keep in mind that the settings indicated on the gauges would be maximum settings, and your best results usually be much lower. As an example, the rear has a max setting of 45, while they usually operate best somewhere between 32-40. Rear trailing air is used when machine is going rear to front and has a max setting of 10, but best results are usually from 3-5PSI.
You could increase the rear bumper dwell time to improve quality in that area, and you could also slow down the trunk wash speed so it travels slower after the rear wheels are detected. If you slow it down though, you will need to also adjust the timer that tells it how far reverse to travel (D970). Please use caution on this one though because you really just want the top brush to get to the top part of the roof. As MGSMN mentioned above, you don't want the front arms to be able to come in behind the rear of the vehicle.
