1999 supra

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I have a 1999 supra legacy that the guages worked form about 3-5 minutes this season, the speedometer stuck and now no guagfes work. I have tried two different mdc(marine Data Concentrators and still no guages or speedomter are working, I do not know what could be wrong, anyone with this problem that could help out?

Confused/frustrated
Bryan

[Ed Obermeier]

I had the exact same problem with my 2000 Legacy. The issue is with the control module for the guages. At least on my 2000 it's mounted on the drivers side in the rear of the boat next to the gas tank, behind the panel that covers the tank and under the tray in the trunk. Real hard to get to.

There are two small tubes (hoses) that attach to the module, these are the lines from the speedo pickups. Inside the module where the hoses attach are pressure switchs that read the speedo pickup and feed the signal to the speedos on the dash. There is an o-ring that is supposed to seal out the water from the pressure switch. The o-rings give out and allow water into the module, and we all know that water and electronics don't mix.

Had mine replaced twice, both times covered under warranty by Supra. Had to argue with them about the 2nd one but they finally replaced it no charge. First time was early in my 2nd season of ownership with under 100 hours on the boat, second one later that same year. After the 2nd replacement I left the hoses disconnected from the module and plugged the lines with golf tees to keep the water from coming into the boat. Of course leaving these disconnected leaves you with no speedometers. I had added PerfectPass to the boat so not having a speedo working wasn't an issue.

Remove the panel that covers the gas tank and look next to it on the drivers side, you should see an ECM with a large modular plug in the side and a couple of small hoses attached. Disconnect and remove it (mark the corners with a magic marker so you can line up the screws to remount - major PITA), then shake it to see if you hear any water sloshing around in it. If so you've discovered the problem. This is a known issue to Supra and they changed designs in either '01 or '02 to solve the problem affter replacing quite a few of these ECMs, or so I was told by the dealer.

Ed