I have an 05 38 Fountain Lightning with 525's. For some reason on the Port side the Oil Pressure, Oil Temperature and Water Temperature stopped working. There's power to them but there not moving. RPM, Volts and water pressure as well as all the lighting work. Tried unplugging the main harness but didn't help. Is there a plug on the motor that may have come undone? Hate when they don't work.

Thanks

The AGI box may be bad, thats where the digital signal for senders get converted to analog for the gauges on the dash panel.

http://www.mercruiserparts.com/Show_...%28Ignition%29 are you talking about part number #56,,,when you say AGI box???

Yes that's the part.

it must be a ground,,because each gage has its own wire,,but the ground goes to all the gages,,,looks at part #56 on my post,,,find it on the back of your engine,,follow ground wire from agi box,,,,or check the ground for the gages at dash,,,

you can see the groung wire going into a connector on my 525 engine

I was away for a cpl of days and didn't check up the forum. Wow thanks guys, gonna try it out tomorrow 1st thing. I'm sure that is the problem.

Alright its fixed!!! Turns out it was the ground wire. I just recently had to remove the inside head on the Port motor. A valve got stuck open. Sure that is pretty rare for an 05 525 with only 235 hrs on it. Guess when I did the job I accidentally broke the wire.

Thanks for pointing me in the right direction!!!

Guys Im haveing a simular problem. The problem I have is only with one guage. I changed my oil temp guage. It was a gaffrig guage before and I bought a Livorsi guage to replace it with. This guage is an oil temp guage. I put on the Livorsi guage exacley like the gaffrig guage was hooked up and nothing at all. In fact the guage is pined down on the left side and has not moved since I hooked it up. I bought the new sending unit too but I can get my hand on the sender to change it. Do you think the two guages hook up different?? I did notice the light inside of each ic different. Let me know your thought's

The sender sends a certain amount of volts to the gauge to operate, the volts required for the gauge to work properly depends on the manufacturer. The new Gaffrig gauges will not work with Livorsi senders, this may be part of your problem. You could try the new gauge on the other motor to see if it's the sender or not.