Here's a real head scratcher

[Wingnutt]

About a month ago I had lightning hit a tree about 8' from where I park my boat. It came into the boat through the metal landing gear of the trailer and fried the trolling motor, the fish finder, the battery and the radio. I thought I had everything straightened out, but yesterday when I was out (for the first time since) I was anchored while fishing, and seeing how it was starting to get dark, I put the stern light into it's socket and turned the lights on. Now here's where it gets weird. With the key off and the light switch set for the running lights, the fuel gage goes up to the 3/4 tank mark (with a full tank). If I set the light switch for the ancho light, the fuel gage stays on E where it should be with the key off.

Does anybody have any ideas on where to start looking?

TIA

 

[Boatin Bob]

Re: Here's a real head scratcher

Just a thought but on some boats instead of using the more expensive switch for the nav lights they use a cheaper one with diodes to prevent back circuits, check the wiring coming off your switch to see if there are any diodes (lightning may have fried them).

 

[--GQ--]

Re: Here's a real head scratcher

Lightning fried the trolling motor while not in use? That is weird.

Two of your hot wires maybe shorted together. Will be a head ache if you're not familiar with elctricity if this is indeed the case.

 

[Gone]

Re: Here's a real head scratcher

Trolling motor itself is probably OK but the speed controller is probably what got hit.
The running light is pulling some current through the fuel gauge circuit when on but not in anchor position.

Perhaps a carbon track(arc residue) in the light switch or the ignition switch. I'd bet on the ign sw.
I wonder why the engine electronics weren't affected?

GQ's right, it's going to be a PITA to find.

CD

 

[xtraham]

Re: Here's a real head scratcher

ground wire somewhere is burnt off,

 

[Wingnutt]

Re: Here's a real head scratcher

Thanks for all of the ideas!

I had thought of the ground because that was the problem with the bow light. I haven't thought about carbon tracking though, but I will try to check it out.

The odd part is that the fuel gage is located on the right side of the dash and the light switch is on the left side of the dash (about 20" apart). I also noticed that the volt gage is acting up too. When you first turn the key on (engine off) it will rise up to about 11v then slowly drop down to 10.2v. If I turn the lights on it will drop all the way down to below 10v. HOWEVER my fishfinder still shows 12.8v the whole time. Also the volt gage is wired kinda odd. It is tapped into the hot wire that runs between the dash lights.

I think I will get a buss-bar and completely re-wire the ground circuit from the battery forward....that oughta be fun.

 

[bruceb58]

Re: Here's a real head scratcher

You can temporarily run a long ground wire from the running lights back to your battery to see if that is the problem...I bet it is.

 

[MASTER Brian]

Re: Here's a real head scratcher

I don't know if this will help or not, but I recently had a short (open?) in one of my trucks. Everything worked, but for some reason the battery kept draining if it sat long. I finally found out that you can hook get a test light (I took a automotive bulb and soldered some wire to both contacts) . Then unhook the + battery cable, hook one wire from bulb to + terminal on battery the other wire from bulb to the + battery cable. You start pulling fuses until the bulb goes out. When the bulb goes out, you have the bad circuit!

Again, I don't know if that i will help, but I'd think it would.

I haven't found the problem yet in my truck, but at least the battery doesn't drain.

Good Luck!!

 

[Wingnutt]

Re: Here's a real head scratcher

UPDATE:

After spending the better part of two weeks off and on laying in a bowl of black spaghetti I finally got all of the ground wires replaced and guess what....everything is working properly again. d Thanks again for all of the suggestions.