Need Help with an Electrical Issue - Ranger 375V

[Ranger Blues Man]

I am having a issue with my 1988 Ranger 375V bass boat. I have lost power to the nav lights, courtesy lights, and bilge pump. Everything else works fine. Checked the fuses and they all look okay. Where do I go from here to track down this issue? Thanks.

 

[Silvertip]

Break out the voltmeter and"
1) check for voltage at the nav lights. (yes or no)
If no go to 2. If yes, check the bulb and internal connections.
2) Check for voltage at the "load" (light) side of the NAV/ANC switch with switch set to NAV. (yes or no)
If no go to 3. If yes, there is a wiring problem between the switch and light.
3) Check for voltage at the "line" (input) side of the NAV/ANC switch. (yes or no)
If no, go to 4. If yes the switch is bad.
4) Check wiring from the fuse/breaker panel to the line side of the switch.
5) Repeat 1-4 for the courtesy lights

You said you looked at the fuses. Did you check them with an ohm meter or simply replace them with known good versions.

 

[gm280]

The fact that those circuits all stopped working together points to their common ground OR supply voltage. So like Silvertip stated above, break out the meter and start checking things. But once you do find the problem and fix it, it would be a great idea to clean any connection from the battery all the way through the helm and everything electrical. Because this could be the start of corrosion issues and you can head all future problems off by such cleaning contacts and connections.

 

[Ranger Blues Man]

Thanks Guys. I will start checking things this weekend.