Potential solution for low voltmeter readings. 1999 E22

[Sammamish Skier]

I've been chasing low voltmeter readings at the dash for awhile and I finally made a breakthrough.

I've replaced the main runs from the battery switch to the dash and upsized them. I replaced the ignition switch and also ran new independent supply wires to each of the circuits at the dash. Each of these marginally improved the voltage.

Today I tracked the supply to the gauges back to the ignition on circuit (purple wire) and discovered that the supply to the gauges passes through the kill switch and associated harness where it looses significant voltage. It's enough to keep the ECU happy but not to get accurate voltmeter readings.

I cut and sealed off the original purple supply and tied the gauge power directly to the ignition terminal on the ignition switch. No more low voltage readings. 

Easy way to tell if your boat is setup like this, turn on the ignition and pull the kill switch. If the gauges die then their power passes through the kill switch.

[HCollado]

Hum ... I'll try this. Thanks   
 

[cyclone]

That is very interesting, I'd assume its not the millenium dash. where did you break the gauge supply wire, at the kill switch or nearer the gauges?

I did your test and my gauge voltage is supplied via the kill switch as you describe. I will see what I can trace later today.

[Sammamish Skier]

I cut the return supply from the kill switch near the gauges and then wired it directly to the ignition on output on the ignition switch.