Oil Pressure guage with light built in
 

Need some help, I have a Gaffrig oil pressure guage with built in indicator light in my 2001 fountain 35, at 3000 rpm it shows about 30 psi no light. anything above 3500 rpm the oil pressure guage jumps from 15-35 psi and the light in the guage comes on, but it also has another horn and light that is connected to another switch so I don't think it is loosing oil pressure. my question is if the guage pressure never falls below 15 psi how does the the guage know that the boat is not just at idle. does the oil pressure guage have an input fron the tach to tell it that at this rpm it should have a certin amount of pressure. Bottom line, what turns the light on in the oil pressure guage. when the key is turned on and motor is not running the light will come on, this tells me that no pressure turns the light on. does it have a set point.

The dash oil pressure gauge is independent. Not tied into the tach. The red gauge indicator light is lit from a zero reading from the gauge itself. It has no seperate input for the lite itself. If the lite comes on with a pressure reading, I'd say the gauge is faulty. Exspecially since the gauge bounces 15-35. I'd think the sender is fine since the light lites up with pressure.

Just swap the signal leads on the guage from PT motor to SB motor to double check.

That's what I was thing but I can't put it back in the water till March, so I guess I have to wait. guess I won't be able to get a matching one. wonder if it could be repaired?

Might give Livorsi a call. NOt sure if they can repair them or if they just swap out the insides. I'd think they could simply reinstall your face plate on a new gauge if all else?? I've also bought a replacement off them to stay with the Gaffrig label. Didn't want a single 'Livorsi' labeled gauge They still had some of their original Gaffrig labeled gauges in stock. Been a couple yrs ago though.

I've had to replace a few of my Gaffrig(Livorsi) redline guages because of simlar issue. Gauge would go a little crazy and the warning light would come on. Turn the key off and restart and all would be fine. I got some replacements off ebay.