Dash Gauges Quit Working

[Glennman]

On our way home today from a 1000 mile trip down the Oregon coast, our dash gauges quit working at about 25 miles from home. The speedometer is stuck at 60 mph, and the other gauges are stuck at around where they were reading when they last worked. The fuse in the front J-box is good ("gauge power", 12 volt, 5 amp fuse), and there is power at the fuse. Otherwise, that's the only fuse that appears to be applicable.

I checked a bunch of different ground connections to no avail. I checked the system for codes and functionality of signals from the computer, and that all checks out. The bus is a 2002 MCI D4500 with the multiplex system.

Other than that, we had a great time and made it home okay! Any ideas?

[luvrbus]

Sure sounds like the chassis computer has a problem I don't how you can check those without the MCI software, it has 3 computers   

[Glennman]

All fixed. In my conversation with the MCI tech support, we determined that the issue was related to my recent installation of a switch I installed to get the Jake Brakes working. In that attempt, I installed a switch in the dash with the hope of being able to get the Jakes working (that had been in the bus since new, but unused). I also had the ECU checked to make sure they were "on". However, they still didn't work, so I sort of gave up on that for a while. In the meantime, apparently my monkeying with the Jake issue caused some kind of overload on the A-2 and A-3 modules located under the driver's window, which a 10 amp fuse blew in each of them (the F-8 position on the front of each module). I uninstalled the Jake switch (under the advice of MCI) and replaced the fuses, and now everything is back to normal. I didn't think to replace one at a time to see which one did the trick, but at any rate, the gauges light up, function, and the dash buttons are lit up again as well.