More than just the gauges..Need Help

[tp1188]

I recently purchased a 1999 Malibu Sunsetter LX. I knew that the gauges were not working, and figured that a simple fuse change would correct the problem when I got the boat home. However...I am now finding that there are not actually any fuses to change, only "fuse reset boxes". The "fuse" box for the bilge pump seems to have been tampered with because there is no pop-out button. The speedos work, the depth finder works, the back-lights in the gauges work and both of the 12v DC sockets work, but none of the other gauges work or "reset" when I turn the key. I have tried the reset trick by undoing the safety lanyard and then replacing it, but the gauge needles never budge. The Tach needle is stuck around 1800 RPM, and most of the other gauges are not at zero. Also, the horn, the bilge pump and the blower do not work. The blower was working, but now it is not. I've read many "gauges not working" threads, but none of them seem to have my same issue. I need some kind of advice please.

[Sethro]

Sounds like the computer that runs the gauges (MDC it's called) is bad. It can have all sorts of symptoms. The second time mine went out the only thing not working was the tach, but it turned out to be the MDC and not the tach itself.

[tp1188]

I found a troubleshooting guide for the MDC 1600, and I'll be checking voltages in a little while. I was just wondering if it might be something besides the MDC. I took off the dash and checked everywhere for loose wires. None found. Maybe a detailed investigation into the MDC voltages will provide some sort of answer.

[99response]

Those "fuse boxes" can and do go bad, move around to an open one (with the same amp rating of course) and see what happens.

-Chris

[tp1188]

ordered new MDC, and took out the speedos (tubes were filling dash and previous MDC with water). hooked up new MDC and everything works great.

[lf133]

ordered new MDC, and took out the speedos (tubes were filling dash and previous MDC with water). hooked up new MDC and everything works great.

I have ordered a new MDC but was told it would take 3 weeks to get because they were on back order. Not good news for me. I do have a question. My boat stays in the lake and the MDC is removed so I got some water up the speedo tubes. Do you think there will be a problem with hooking it back up to the new MDC and not drying out the tubes? (I was going to try to blow them out but they will not be sitting out to dry for days.) I believe they run off air pressure not water. I would hate a little water in the tube to toast the new MDC. Any thoughts.

[DEVIN]

I found a troubleshooting guide for the MDC 1600, and I'll be checking voltages in a little while. I was just wondering if it might be something besides the MDC. I took off the dash and checked everywhere for loose wires. None found. Maybe a detailed investigation into the MDC voltages will provide some sort of answer.

I'm having similar problems with my gauges not working, but everything else is. Can you send me the link for the troubleshooting guide? I think mine is the Medallion 1600.

[wienrdog]

Docs are available here...

http://www.epicmarine.com/docs/MDCtrouble.PDF

http://www.epicmarine.com/docs/Digital_Instrument_Guide.pdf

Thanks to Swampy for the original links.