Temperature Gauge NOT WORKING this season

[rushman]

Finally got the boat out of storage and did the normal DE-winterization and the boat fired up before it even turned over a full revolution and worked awesome as it usually does. I installed a Raw Water Strainer in it this year (with help from the crew) and it works great too. BUT,

The temp gauge does not move from the bottom.

Could this just be a temp sender??? Do they work on a ground system because when I use a test light there is no power to the wire. And it looks like there could be two. A two wire one that is installed in the intake maniford vertically and a one wire one installed horizonally facing forward just port to thermostat housing.

The engine is warming up. It blows hot air out of my heater. The exhaust warms up but doesn't get hot and everything seems normal, except for gauge not reading. Every other gauge works great and the MMDC is one season old. I can't see any breakers that are "broke". It has the multi-function gauge that has temp, fuel, oil pressure and charging. Just the temp is not working.

Any suggestions...

Thanks.

Kevin

[rushman]

I forgot to mention...

It has a 2004 Monsoon 340 Hp in a Sportster.

Kevin

[RTS]

On your Monsoon, you have two temp sensors. One feeds the Engine Management Computer and the other feeds the guage on the dash. The one that feeds the guage if I remember correctly is the one with the single brown wire to it.

I'd pull that brown wire and make sure nothing changes on the guage. Then maybe ground that wire and see if it pegs your temp guage to the hot position. If it does, that temp sensor is the problem, and is a (relatively) cheap and easy part to replace. If there is no change on the dash guage with the wire being free (open circuit) and the wire grounded (closed circuit) then the problem lies in the wiring or the guage. Make sure your key in on when you do this, of course.

Hope this helps.

Edited May 25, 2009 by rts

[rushman]

On your Monsoon, you have two temp sensors. One feeds the Engine Management Computer and the other feeds the guage on the dash. The one that feeds the guage if I remember correctly is the one with the single brown wire to it.

I'd pull that brown wire and make sure nothing changes on the guage. Then maybe ground that wire and see if it pegs your temp guage to the hot position. If it does, that temp sensor is the problem, and is a (relatively) cheap and easy part to replace. If there is no change on the dash guage with the wire being free (open circuit) and the wire grounded (closed circuit) then the problem lies in the wiring or the guage. Make sure your key in on when you do this, of course.

Hope this helps.

I think I did this. Can't remember for sure...I tried a few things. But that being said I do not know if I was getting a good ground when I grounded out that single brown wire. I will double check that and do it.

Any guesses to why it was working perfect when I put it away and now nothing???

[electricjohn]

IIRC, the water temp sender for the gauge has a single green wire to it. Also IIRC, the MMDC only sends a 5 volt signal through the gauge and then to the sender where the circuit is completed to ground. I believe the gauge operates with a 4-20 milliamp signal. If you disconnect the green wire at the sender and measure the voltage to ground, you should see 5 volts. You will need a meter with a rather high input impedance, such as a digital multi meter. If you get your voltage, then the sender is shot. Even though the MMDC system works with only 5 volts, a regular 12 sender is the the replacement. That is the way the system is calibrated.

edit; The water temp signal to the gauge also travels thru the cannon (engine to helm) plug. This plug has been a weak link for the lower voltage signals. Try wiggling the cannon plug and see if your signal comes back to the gauge.

Edited May 25, 2009 by electricjohn

[rushman]

I will try all this stuff. Thanks

[reggie]

what worked to resolve this issue?

[rushman]

what worked to resolve this issue?

Actually, I went back to the cottage the next week and the temp guage worked perfectly without doing anything, so I thought everything was fine. But again just this weekend the temp gauge "got suck" at around 130 degrees and was suck there. So I don't know what the heck???

[skier92]

Have you checked the connections suggested in previous posts? Intermittent problems with electrical devices often are the result of loose connections/bad grounds.

[eyepeeler]

Any chance that a rodent got in your boat over the winter?

[rushman]

Have you checked the connections suggested in previous posts? Intermittent problems with electrical devices often are the result of loose connections/bad grounds.

I have not checked the cannon plug, but the ones to the senders I have. I will have to take apart the cannon plug and look at it. Should I use a di-electric grease in the cannon plug??

[rushman]

Any chance that a rodent got in your boat over the winter?

Definitely NOT, thank goodness.

[electricjohn]

Have you checked the connections suggested in previous posts? Intermittent problems with electrical devices often are the result of loose connections/bad grounds.

I have not checked the cannon plug, but the ones to the senders I have. I will have to take apart the cannon plug and look at it. Should I use a di-electric grease in the cannon plug??

There already is di-electric grease in the cannon plug. Too much in my opinion. I was having problems with my gauges and actually cleaned some of the grease out of the connections which solved my problems. Most of the connections are 12 volt, but the conections for the gauges are only 5 volts, operating in the milli-amp region. They were the problem connections for me. Since cleaning the grease out in 2004, my gauges have been troublefree. If you plan to unplug the cannon, I would mark it somehow, as I found out, it will go back together more than one way.

Edited June 16, 2009 by electricjohn

[rushman]

Have you checked the connections suggested in previous posts? Intermittent problems with electrical devices often are the result of loose connections/bad grounds.

I have not checked the cannon plug, but the ones to the senders I have. I will have to take apart the cannon plug and look at it. Should I use a di-electric grease in the cannon plug??

There already is di-electric grease in the cannon plug. Too much in my opinion. I was having problems with my gauges and actually cleaned some of the grease out of the connections which solved my problems. Most of the connections are 12 volt, but the conections for the gauges are only 5 volts, operating in the milli-amp region. They were the problem connections for me. Since cleaning the grease out in 2004, my gauges have been troublefree. If you plan to unplug the cannon, I would mark it somehow, as I found out, it will go back together more than one way.

Good Tip. I would never have thought to mark it but I will. Thanks.

Kevin