For some time now both my 360 and Excella monitor panel tank indicators have been non functional. I looked high and low for a functional replacement to no avail. I bought used ones which were either like mine or worse! I called the original mfgr and they had long since stopped stocking these. I then called AS, and they referred me to the former owner of the company who is now the owner of the company who has none left, nor do they repair these any more.
Airstream suggested new level sensors, and a new monitor panel, to the tune of more than $3k.... unacceptable! I have a system in place, and I was going to make it work!!!
I decided to take the panel to the bench and give it better look. Upon testing I found the same series of transistors failed on all 7 of my suspect monitor panels. Simple enough, I was able to obtain replacement semiconductors, and voila, my monitor panel is working 100% again.
All my boards worked to read battery, and propane levels, but none of the tank level (fresh, black, grey) indicators worked at all. Since the repair, I have been able to calibrate all functions to my liking, I now have an exact way of reading the vital stats of my Airstreams! Onkly once did I have a back up of the grea tank into the shower... that episode alone was a big enough pain to ensure I keep track of my levels.
For battery reading, I have the panel calibrated to illuminate "Full" at 12.6 volts with nominal load (per my own usage), LPG monitor is calibrated "full" after a 85% fill up on the gauges on the tanks. Fresh water is "full" when I begin to hear the gurgle from the vent, black and grey are both set to "full" per filling to 90% of the tank volume by manually filling the tanks with 5 gallon water jugs.
The repair cost about $50 using top shelf semiconductors from TI. I made a few other mods also, like making the AC ON/ shore power LED illuminate now that all my converters have been modernized.
I got used to not knowing the levels of my tanks.... an inevitable time bomb. I'd be happy to share the info to anyone who also has failed monitor panels. I'd even offer to do the repair work for you if electronic repair work is beyond your capability. I'm currently working on an instruction sheet for the repair.