2001 Mobius MDC location ??

[Tydogg]

After countless hours of research not only online in this forum but others as well .....I for the life of me can not find a MDC unit. I have check under the dash (the complete dash guages and all are removed) , checked under "glove box" battery location , checked rear of boat under every panel (which are all removed as well). ....nothing . No MDC , No breaker panel, no fuse panel literally nothing . I was told to follow the speedo tubes to the MDC . I have 2 speedos with grey wires to each . Followed those to the back to absolutely nothing .

Any suggestions as to where to go from here ? The guages were removed because almost all either weren't working or only for odd moments they would work then stop .

[bergermaister]

Uh, what's an MDC unit?

I can do some tracing and take pics if I know what I'm looking for.

[Tydogg]

MDC 1600 that operates the guages? That's the issue I am having with this boat Haha!! I haven't seen a single fuse box , breaker or the MDC unit which is apparently a black box that your harness connects to for your guages that can be located apparently under the dash , by the battery or in the transom on the starboard side !?! This is my first Moomba boat and have had major issues this far not only finding parts but trying to repair it

[Tydogg]

This is apparently it . The speedo goes directly to it

[Tydogg]

Btw from your picture on your profile we literally have the exact same boat ....colors interior etc .

[Darter]

If your boat has one, it had to be very close to the gauges. I replaced my paddlewheel and ran the wire from the hull all the way up to a connector right below the speedos.

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[Tydogg]

If your boat has one, it had to be very close to the gauges. I replaced my paddlewheel and ran the wire from the hull all the way up to a connector right below the speedos.

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Did you run it directly to the speedos? Or did you tap into the harness that connects to the board behind the dash ? All my guages pretty much stopped working. Took them all out including the dash surround. Cleaned each connector , replaced all connectors with heat shrink , cleaned the circut boards (large one and small one for the toggles). Went to reinstall and the guages will not work ....none of them at all will even move . Thought it might just be a ground but the circut board is grounded through the harness . Then I was told it could be the MDC unit , or a breaker etc etc....cant find anything of a sports on the boat ...but they HAVE to be protected somewhere via fuse or breaker or MDC something ....otherwise all those guages ame toggles are open to being blown. I'm missing something here and the bad thing is I do wiring for a living Haha!! (Not for boats or auto though )

[Tydogg]

Did you run it directly to the speedos? Or did you tap into the harness that connects to the board behind the dash ? All my guages pretty much stopped working. Took them all out including the dash surround. Cleaned each connector , replaced all connectors with heat shrink , cleaned the circut boards (large one and small one for the toggles). Went to reinstall and the guages will not work ....none of them at all will even move . Thought it might just be a ground but the circut board is grounded through the harness . Then I was told it could be the MDC unit , or a breaker etc etc....cant find anything of a sports on the boat ...but they HAVE to be protected somewhere via fuse or breaker or MDC something ....otherwise all those guages ame toggles are open to being blown. I'm missing something here and the bad thing is I do wiring for a living Haha!! (Not for boats or auto though )

Currently each speedo has a grey wire with a Ground, Hot and Signal I'm guessing . Each wire has 3 wires in it . Both run to the rear and both run under the fuel tank one on each side

[Darter]

Sounds like you're set up differently. I just had one cable to the paddlewheel in the middle of the boat. Hot, ground, speed.

My cable ended at an inline plug hanging behind the gauges. I didn't trace beyond that point tho.

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[bergermaister]

You didn't clarify if you are a D-Drive or V-Drive. Under the dash there are no fuses, or MDC. Only a circuit board for your manual switches and a pass through for the engine wiring harness to your gauges.

https://i.imgur.com/pKef678.jpg

On mine (V-Drive) under the distributor (technically the back of then engine) and on top of the transmission is the main engine wiring harness connections. That's really all there is on these boats - pretty simple.

https://i.imgur.com/qy1oX9h.jpg

https://i.imgur.com/QCgdB8V.jpg

https://i.imgur.com/XMf7yNe.jpg

I would look there first for any vandalism.

I didn't trace the speedo cables/harness because it's 90 degrees in my garage, I have to go to a neighborhood function in about 15 minutes, and I need a beer or two first.

[bergermaister]

Another solution to at least your speedo problem is something like this... :cool:

https://i.imgur.com/Dxgs7Bw.jpg

I have doubts though that there's an MDC hidden anywhere in there - yours or mine.

[Tydogg]

You didn't clarify if you are a D-Drive or V-Drive. Under the dash there are no fuses, or MDC. Only a circuit board for your manual switches and a pass through for the engine wiring harness to your gauges.

https://i.imgur.com/pKef678.jpg

On mine (V-Drive) under the distributor (technically the back of then engine) and on top of the transmission is the main engine wiring harness connections. That's really all there is on these boats - pretty simple.

https://i.imgur.com/qy1oX9h.jpg

https://i.imgur.com/QCgdB8V.jpg

https://i.imgur.com/XMf7yNe.jpg

I would look there first for any vandalism.

I didn't trace the speedo cables/harness because it's 90 degrees in my garage, I have to go to a neighborhood function in about 15 minutes, and I need a beer or two first.

Thanks so much !! These will help tremendously!! I traced the speedo wires and they both run to a speedo wheel one on each side of the rear. Will start where you said and work my way back . Thanks so much guys will keep ya posted

[Tydogg]

The grounds on the circut board , under the guages main harness etc ....where do they go ? Your pic looks like they go UP from the circut board

[aerolland]

That year SHOULD have a MDC. Mine was a DD but should be similar - the key is to follow the pitot tubes, they plug directly into the MDC brain. They're hateful and prone to damage. Also, no longer available from Medallion...

From a post I just replied to:



Very familiar with that darn MDC...

https://i.imgur.com/e3pVxUTl.jpg



It's located in this right rear corner behind the flexible carpet strip (in the rear locker). At least 2 screws to remove at the floor level, about 1' in from each end. Entire flex strip comes out. Follow small diameter pitot tubes (speedometer hoses) back to brain. This is how they fail BTW - diaphragms fail internally then water gets pumped into the control boards from the speedometer pickups.

https://i.imgur.com/ordhzNRl.jpg

[Tydogg]

That year SHOULD have a MDC. Mine was a DD but should be similar - the key is to follow the pitot tubes, they plug directly into the MDC brain. They're hateful and prone to damage. Also, no longer available from Medallion...

From a post I just replied to:



Very familiar with that darn MDC...

https://i.imgur.com/e3pVxUTl.jpg



It's located in this right rear corner behind the flexible carpet strip (in the rear locker). At least 2 screws to remove at the floor level, about 1' in from each end. Entire flex strip comes out. Follow small diameter pitot tubes (speedometer hoses) back to brain. This is how they fail BTW - diaphragms fail internally then water gets pumped into the control boards from the speedometer pickups.

https://i.imgur.com/ordhzNRl.jpg

There is no MDC on this boat I assure you Haha!! I have literally ripped the interior out of the boat including the ski locker ....nothing. The speedo "tubes" which are 2 wires with 3 wires inside each go to speed wheels one on each side of the rear of the boat . Guages still arent working. Hooked everything up the way it should as I downloaded a wiring guide from Indmar and still nothing . The ballston, bower etc every single toggle works off the board but no guages . Ignition works properly as well it's literally just the guages . Put the guages on a bench and tested all , all tested good . There is something missing that I'm not picking up on . On the circut board there is multipul grounds which I believe come from the breakers in the panel above . The actual guages are gro unk ne through the wiring harness back to the engine where they connect into relays then into a small fuse panel . Have tested all the relays and they are all good however the fuel pump fuse was popped and melted . I'm now wondering if it's a ECU issue .....I wouldn't thnk this however I'm running out of options at this point

[Darter]

I'm almost certain that mdcs are only used on boats that use pitot pickups for speed reading to convert water pressure to an electrical signal.

Paddlewheels are an electro mechanical device, so no mdc is needed.

Pretty sure. ;)

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[Tydogg]

I'm almost certain that mdcs are only used on boats that use pitot pickups for speed reading to convert water pressure to an electrical signal.

Paddlewheels are an electro mechanical device, so no mdc is needed.

Pretty sure. ;)

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I believe that's correct . Mine run to speed wheels on each side and run directly to each speedo up in the dash