Dead Gauges - 00 Supra Launch

[Launchman2000]

I bought this boat last month and all the gauges except water temp do not work. The gauges do light up and the hour meter inside the tach works. I didn't think it was any big deal since I got a good deal but the boat mechanic is a little puzzled, he said the gauges all tie into a central black box, does that sound like the culprit here? I am out of town now, not much I can do but I can pass on any info to him. Thanks for any help.

[TX skier]

I don't know if this will help but... I have a 1999 Santera that the gauges come and go. I went behind panel and unplugged them one at a time. I got to the tach, and the rest came to life. I called Medallion Instrument and just need to order a new tach.

Hope this helps.

David

[Launchman2000]

Thks, I'll pass it on, he may not have tried that yet.

Hal

[PoPz]

This could sound dumb, but trust me in my case it made a big difference with gauge problems, try cleaning every connection, to the gauges and where they connect to the ignition and where they connect to the fuse panel and where they eventually connect to the different parts of the engine i.e. ignition coil, alternator, etc etc..

It may do nothing, but it may fix your problems. Boat connections get beat up, crusty and wiggle lose in transit on the trailer and when getting tossed around on the rough water..

That black box is probably the alarm and it could also be a culprit.

[Launchman2000]

Well I finally got my boat out on the water and all gauges work correctly now except fuel tank and speedo. Speedo is not that big of deal since an iphone and GPS work fine. I suspect I need a new sending unit for the fuel tank level. I topped it off before I got out on the water and it pretty much stays on empty the whole time. The little black box was about $350 from Medallion Instruments. Thanks for the suggestions.

[docdrs]

did you put in a new mdc unit?

[Launchman2000]

Yes I think that is what it is, flat rectangular box in the dash where all the gauges tie in. The boat mechanic I used was not that experienced with supra boats.

[bobbyT]

Welcome to the club...year 2000! I bought a Legacy 2000 this summer and the gauges were not functioning. Love the boat and the sellers disclosed the problem openly and I was aware of the issue. I will attach the link from a discussion had in 06 about this same issue. I did not attempt to resolve the issue because the extra time I had was spent on the lake and enjoying the sweet boat! Unfortunately it made for some challenges with disconnected gauges (speed and fuel). So here is what I have and I will be working on this project soon (hopefullY)

https://forum.supraboats.com/showthread.php?t=1353&highlight=2000+supra+legacy

To order the control unit for the gages give medallion a call at 616-847-3700. They are based out of spring lake MI. The control unit is around $300.

Launchman2000, did you install one of these control units? Or just look into them?
I am considering putting in the new unit and not attaching the speedos (see above link). Some suggested using a handheld GPS for accurate speed and no more gauge problems. Do all GPS' read accurate speeds? Any inexpensive speedo GPS suggestions?

So, any expereinced boaters that have enjoyed the 2000s can help us both out.

Just took the boat and dock out for the year:(

[docdrs]

I had a 99 moomba outback and replaced mine after about 5 years....the problem is with the speedo lines. moisture/water would get up into the unit , freeze and eventually crack the housing and water illl get right into the unit.
You have to disconnect these lines during winterization to prevent this....some say even remove the mdc unit and store it inside your home.....fyi

[td in nc]

I just purchased a 2000 Supra Launch which I am making a list of repairs. Top on the list is getting the gauges working. The temperature, oil pressure and gas gauge do not work. The speedo and tach work. After reading this and other threads, it is unclear to me if the control unit is bad, would the speedo and tach still work? I will chase all the grounds and connections this weekend, but do not want to waste my time as it sounds like the control units had some real issues. The previous owner said the gauges only worked for him a few months after he bought it 4 years ago, he chased the connections and ground, but never found anything.

I hope to post a pic of boat soon. Currently have a 85 Ski Nautique 2001 which we have outgrown.

[99bison]

The gauges in my 01 launch have all been replaced, I replaced about half last year, the rest by a prior owner. They were faria brand and under lifetime "warranty" which meant sometimes it was cheaper to a get a replacement via that route, other times could find cheaper online.

There was no control unit for me, they all appear to run separately and replacing all of them would be cheaper than the control unit pricing listed here.

Faria has a testing procedure posted online (insanely slow www site) also to see if gauge is bad, so should try that if you have those.

[td in nc]

I was thinking of replacing the all of the the gauges as well. The only one which is a concern is the gas gauge. Did you replace your gas gauge and if so any recommendations?
Thanks

[99bison]

I think the gas gauge was already replaced. I went with Chesapeake white with stainless bezel for everything because that's what the two working (already replaced) ones were.

The only one I had a hard time finding was the speedo, so I sent that into faria and asked for the Chesapeake instead of the supra one I sent in - so it would match the rest of the new ones. If someone wouldn't have replaced any (and thus changed the line colors from red to blue) I probably would have kept the same style as original.

[td in nc]

After running through the trouble shooting guide it seems to indicate the wiring harness is bad. Has anyone replaced the wiring harness or tried to identify the problem? Any help would be appreciated. This thing is driving me NUTS!!

[td in nc]

Okay, after much trouble I finally threw in the towel and went to an electrical shop that had a really good reputation. I asked them to do a quick diagnostic of the medallion gauges and if it was not an easy fix to install all new wiring for independent gauges to bypass the MDC unit. The gauges now work, and it was not cheap, but I chose t avoid the same problem again in a couple of years.

Medallion did send me additional trouble shooting guides for these gauges which I would like to post but the file size is over the size limit for attachments (the are around 100kb) If someone has a way that I can post these, it may help others in the future.

1. test for shared power source
2. Ground test
3. Solution for the problems identified above