Insturment cluster switch questions

[BriceW at webtv.net]

I removed my cluster and soldered the board and applied Stabilant 22A on
all the different connections.
I did not remove the steering wheel but slid it out the right side after
taping the wood paneling.
I had ordered a bulb it from Blau a few months ago and was very
disappointed to find ONLY 11 bulbs in the kit. The cluster has a total
of 21 bulbs. So I will probably be pulling it again in the future to
replace burned ot bulbs. Next time I will order all the bulbs from
Scott.
The speedometer works great now. No jumping! It is right on the money.
I also re-soldered the OK check sytem board to avoid that job n the
futrre.
My questions are:
1. What does the switch do that is brownish red color that is marked
SEUFFER 627? On the other side on the white plastic shell it says 1 2 3
4 5 6 from right to left with Benzin over the 1 and Diesel over the 6
and under that is
RWUSEGRWUSEG
The switch goes from 1 to 6. Mine is in the number 2 position so I left
it there.
2. The other switch is to the right of the brown one.It is black with 3
white buttons
and is marked CK. There is an arrow on this switch pointing up for ON.
All there of my white slider buttons are down for off.
On the other side of this switch on the white plastic is marked -5.10
and under that is a % sign and under that is +0.0.
What does this switch do?