View Full Version : 2004 Mastercraft X start ECU problems

P Mishan
11-17-2011, 06:37 PM
I am having some problems with my gauges, I have been told that it could be the MDC or the ECU.

I know the MDC is the black box under the gauges, can anyone tell me where in the ECU is and perhaps a picture of what it looks like?

any help would be greatly appreciated

11-17-2011, 06:51 PM
What are your gauges doing?

First you should check all your ground cable connections. Check at the grounding block under the dash and the cables at the engine block and battery. Does your battery test ok and is it fully charged? Is the kill switch working ok?

P Mishan
11-17-2011, 07:51 PM
positive on alll above,do you know where the ECU is

11-17-2011, 08:56 PM
positive on alll above,do you know where the ECU is

If you have an MCX engine, it should be near the distributor I believe.
JimN on here should be able to help you out.

11-17-2011, 09:09 PM
pics are always good.

P Mishan
11-17-2011, 09:19 PM
anyone help with pics, i have no idea what it looks like

11-17-2011, 09:40 PM
maybe this will help, not sure if it would effect your guages though.


P Mishan
11-17-2011, 10:09 PM
thats the back of motor?I dont remember seeing that,is it the box that all the switches are plugged into,any idea cost of one of these?

11-17-2011, 10:20 PM
Pic above is the ecm on the engine, the mmdc is under dash which connects the instrument cluster, ecm $1000, mmdc $300-400

http://www.wakeboards.com/MasterCraft-OEM-MMDC-Box-all-Models-2002-2004-p/mastercraft_mmdc_box_02_04.htm?gdftrk=gdfV23113_a_ 7c936_a_7c3435_a_7c508062

P Mishan
11-17-2011, 10:31 PM
is the ECM and the mmdc difficult to change?

11-17-2011, 10:39 PM
No, a few retainer screws and wiring connectors, I don't think the ecm is the problem, more likely its the mmdc, just based on the information I've gotten here.

11-18-2011, 10:03 AM
I had an MMDC box go bad 2 years ago.

the pitot tubes come from the back of the boat into this. and there is water in it. the water froze, and cracked the MMDC box. when I put the boat in the water, water came up the pitot tubes, and fried the electronics in the MMDC box causeing the gauges to go weird.

changed the box thanks to BAWS and it works great.
I have perfect pass so I keep the tubes unhooked at the pickups. and no water gets into it.

P Mishan
11-20-2011, 03:39 PM
if you change the ECU will the hours start at zero again?