Volvo Penta gauges erratic

[mdwells]

1988 Three Bouys houseboat, AQ151C Volvo Penta 4cyl. Was tying up dash wiring harness and noticed the guage cluster pegging at low end as I moved the wiring.

After a little digging, I found what appears to be a diode located in the purple wire from the switch to the voltmeter. I determined that this was where the fault was. When touching the diode, slight movement causes the gauges to peg to the low side.

I have seen no reference to a diode at this location on any wiring diagram or manual. I figure it was installed by a previous owner, but no idea why it would be needed. All other dash wiring appears to be original and untouched.

My question is, can I just remove the diode or may there be a purpose for it. If it's needed, I'll have to replace it since it appears to be shorted or faulty.

Thanks so much for any thoughts...

 

[alldodge]

My question is, can I just remove the diode or may there be a purpose for it. If it's needed, I'll have to replace it since it appears to be shorted or faulty.

That would be a tough call not knowing what gauges go low and what is the switch connected to besides the diode?

 

[mdwells]

Voltmeter, oil pressure and fuel gauge all go low. The switch is the ignition switch. The line with the diode comes from the ignition to the voltmeter, then oil pressure, then fuel gauge.
*** temp gauge too, almost forgot. Connections are at the 'I' (ignition) terminal on the gauges.
Thanks

 

[alldodge]

OK, so from the ignition switch the wire leaves as a purple wire, goes thru the diode and then on to the rest of the gauges. If this is correct, remove the diode and connect the wire back together

Do wonder why someone would do that

 

[mdwells]

Me too...I see no threat of a current backflow or need to reduce voltage at that point. I'll just eliminate it. Thanks for the response.

 

[mdwells]

Took out the diode/resistor this morning. All is well, gauges reading normally and accurate. Thanks