Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Water leaking from Instrument Panel!


Recommended Posts

Hello Bu experts!

I just got my boat up in running, however, I have a leak coming from behind the instrument panel, that drips down onto my ignition switch. My left speedometer fills up with water, and the leak increases as I speed up. Oh, and the left speedometer that fills with water is not accurate.

Is something on my instrument panel gauged by water?

Any help would be wonderful!

1998 Malibu Sunsetter VLX.

Link to comment

There are two tubes that run from the speedo pickup up to the gauge behind the dash. Actually, in the case of a '98 I'm pretty sure those two tubes connect into the MMDC - the black box mounted up under the dash. It sounds like it simply became unplugged.

You should be able to just find that black tube and plug it back into the MMDC and be set to go.

[Edit]

Hmm. Just saw that the speedo itself fills up with water as well??? If that's the case the tube wouldn't connect into the MMDC, so I'm a bit confused. Until you resolve it you should be able to plug it up and continue using the boat until you get it fixed.

Mike

Edited by mlange
Link to comment

Thanks Mike,

Is there an easy way to get to the back of the speedo? or do I have to go up from underneath. I don't have the boat near by, so I can't recall if I can pull the whole dash out or not? as I speed up the speedo fills up, but when I idle, the water drains out of speedo.

Thanks!

There are two tubes that run from the speedo pickup up to the gauge behind the dash. Actually, in the case of a '98 I'm pretty sure those two tubes connect into the MMDC - the black box mounted up under the dash. It sounds like it simply became unplugged.

You should be able to just find that black tube and plug it back into the MMDC and be set to go.

[Edit]

Hmm. Just saw that the speedo itself fills up with water as well??? If that's the case the tube wouldn't connect into the MMDC, so I'm a bit confused. Until you resolve it you should be able to plug it up and continue using the boat until you get it fixed.

Mike

Link to comment

That's what I'm confused by. I thought the tubes went into the MMDC and then a signal wire went to the speedos, so it surprised me that the speedo itself is filling up. The old Airguide speedos had the tube going right into the speedo itself, so if that tube fell off the speedo you'd get water dripping on your legs. But for the speedo itself to fill up it would have been an issue with the speedo itself.

Do you have a picture of your dash you can post?

In short, I'm a little stumped now and think I'm probably wrong on what I thought it is.

Mike

Link to comment

Jack beat me to it, but yes I agree something is cracked. I have the MMDC that mlange is referring to. But I had a similar experience. If you have a tube directly on the speedo, your system must be different. Apparently they changed somewhere between '98 and '01...otherwise we have the same boat. Anyway, on mine the mmdc is the brains that translates the pressure signal from the speedo pick-up to an electronic signal to the guage. Yours must all be done in the speedo itself. The sensor is supposed to work on air pressure. Water flow through the pitot pick-up on the back of the boat will pressurize the air in the black tubes. There shouldn't be water in the lines. However, mine had a small crack up at the mmdc. This allowed the air to escape and water to get up there. I didn't realize this and over winter it froze and cracked my mmdc apart because it took on water like your guage is. So first time out this spring I got the wet leg like you are, and I had to replace the mmdc (and had great help from people on this site). So I just took Jack's theory and made it more wordy. You'll probably have to replace the guage. And BTW, checking those tubes for water is now on my winterization checklist.

Edited by vette-ski
Link to comment

You will probably need to replace the speedo unit as it is allowing air to travel up the line and out the leak. The pressure from the water through the pitot ends up being the signal that makes the speedo needle register the speed. No dead head to allow this to happen due to leak in the speedo. You might get lucky and find that it is either a cracked hose or loose connection (but the fact you state inaccurate rather than non functional) indicates to me it might be internal to the speedo. Not sure if the speedo's for that year were medallion or Airguides, but if the latter, they are out of business.

Link to comment

I'm thinking that the '98s didn't have the mmdc, so the pitot hose would run directly to the speedo. If it were merely unhooked, the speedo probably wouldn't fill up with water. I'm thinking the diaphram or whatever that is inside the speedo to measure the air pressure must be cracked or something. For Royeh's benefit, the mmdc we have been refering to is a "control module", that runs all of the gauges. I am recalling that my '97 VLX did not have one, it just had regular gauges with no "computer" to run them. An easy test is when you turn the key on, the mmdc equipped boats cycle the gauges - that is - the gauges all sweep to the max reading & then back down to zero. A regular gauge would just go up to the proper reading, ie., 1/2 tank of gas, etc. You will have to pull the instrument cluster to access the back of the speedo.

Link to comment

In 98, there were 2 speed gages. une tube per gage. My guess is the diaphramme must have broken. You need to change the gage. In the mean time, flip up the left pick-up. You will not get water infiltration and you still have your other gage.

Link to comment

Quick check...

MMDC = 2 pick-ups one speedometer gage (with pick-up select switch)

No MMDC = 2 pick-ups, 2 speedometer gages

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...