Les, I got my copy this morning I appreciate you efforts. Good info but nothing about the modules so I'll keep digging for that.
I did find calibration info on an old BAC post.......here it it:
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My 2001 has the CMP-20 Coach Monitoring System. Assuming yours has the same system, the programing information that I have is as follows:
1) Place the unit in the Diagnostic Mode. You do this by pushing all four touch keypad buttons on the CMP-20, inside of your coach, down at the same exact time. This takes me both hands and a few tries to accomplish. You will see the display change to raw full and empty data when you get into this mode.
2) Program the TL-II. This is a module located, in my coach, above the water pump bay in the rear of the basement storage area. There are several of the metal boxes throughout the bay and a few of them are located above the water pump bay. They have green indicator lights on them. There is a mini rotary selector switch in the top of the TL-II module with a push button next to it. In my coach, the module must be taken off the bulkhead to access these switches. Calibration is accomplished by adjusting the fluid in the tank to the proper level, selecting the appropriate position on the rotary selector and pushing the button.
Position 0 = no action - switch must be left in this position for proper operation
Position 1 = set empty calibration on fresh tank
Position 2 = set empty calibration on gray tank
Position 3 = set empty calibration on black tank
Position 4 = unused
Position 5 = set full calibration on fresh tank
Position 6 = set full calibration on gray tank
Position 7 = set full calibration on black tank
Position 8 = unused
Position 9 = Restore factory defaults to all tanks
When you push the program button you should watch the green light and count the flashes:
Flashes
1 = Calibration good
2 = 0 selected on rotary switch - no acton
3 = Invalid tank (4 or 8 selected)
4 = Empty calibration error - tank not empty - sensor or channel bad
5 = Full calibration error - tank probably not full - sensor or channel bad
6 = Full calibration error - tank probably over full - sensor or channel bad
3) Be sure the rotary switch is returned to the 0 position. Turn the CMP-20 off and then back on to exit the diagnostic mode. Your new calibration will be retained in memory even if power is off.
Now that I have given you all of this, I need to say that I have never done this on my coach and the manual states that full calibration should not be necessary.
I would assume that a sensor that falls too far outside of the expected parameters would come in as a calibration error.