SIGH My turn for electrical problems...

stereoman405 · 05-06-2009, 05:34 AM

Ok, I need some help here. I think I have a ground fault problem. The brief version, I have two 10 gauge red wires leading from the OEM dual battery switch. One with a 15A fuse and one with a 30A fuse, and I can't figure out exactly where they are going... Judging from my wiring diagram, I THINK one should be for the fuse block and the other should be for the hatch. When I hook one of them up, half of my accessory switches and my blower and nav light switches light up, but nothing has enough juice to actually run.

What makes this more confusing is the following timeline:

1. Open boat up for the season, everything appears to work fine. Never actually started it.

2. Turn OEM Perko switch to 'OFF'.

3. Uninstalled stereo and aftermarket amp. All of which was straightforward. Amp was spliced into a power lead and ground lead behind the dash (horrible job of it...) I had two black mystery wires that were dangling behind the power seat / exhaust / hatch panel. Using the VM they both appear to be grounds, but I haven't hooked them up.

4. I pull batteries out to charge.

5. Mechanic come over, summarizes boat, hooks up one battery, goes to crank it and it turns over for a few seconds then everything goes dead. He leaves it for me to look at.

6. I decide to install a Blue Sea 'Add-a-Battery' kit before I tear into what was causing it to stop cranking (figured it might just be a bad battery). Very basic install. Port battery has trim hooked directly to it, a cable to switch post '1 - Top', and a cable to the ACR 'terminal A' . Starboard battery has cable to switch post '2 - Top' and to ACR 'terminal B'. The starter is on switch post '1 - bottom' , and the two aforementioned red wires and bilge wire are on switch post '2 - bottom'. (All of this was verified with Blue Sea.) ACR is grounded. In the 'ON' position I get the 'switch light up problem 'and no crank, but in the 'Combine' position the engine cranks and my switches still light up.

So my problem is two fold. For some reason I get no crank from the port battery when its on its own, and I'm getting the apparent ground loop issue.

What would really help is to know where all the ground panel locations are, what these two red wires are for, and what is the best method for checking for a ground fault?

stereoman405 · 05-06-2009, 03:47 PM

Update.

I went out this morning to take another look at this, and either I was smoking something last night, or the ground fault gremlins are being real bastards.

I left a trickle charger on last night so both batteries would be topped off. With BOTH of the pesky red wires I mentioned last night completely disconnected I turned the switch to 'On'. Immediately the switch lights on the dash lit up and I heard a soft whine from the blower. Turns out the blower switch was on. So I turn it off and the switch lights all shut off, I turn it on and they come back on again. Getting excited, thinking I just narrowed the problem down to the blower, I start going through all my switches one at a time and sure enough almost every switch brings the problem back. Only difference is that when I hit the defogger everything was shorting out, and when I turned it off it stayed shorted.

This means that the majority of my accessories are getting power from the starter, since that is the only thing hooked up to the Blue Sea switch. What all should be terminated there?

On my second issue, it looks like I may have gotten a bad selector switch from Blue Sea, which they are sending me a new one.

stereoman405 · 05-06-2009, 04:16 PM

Forgot to add that this boat is virtually corrosion free. All of the connectors I've pulled and fuses I've checked have been clean. I figured this might help narrow down the problem since I'm not already fighting that battle.

Could a faulty switch cause this? They seem pretty robust and full proof. Would it more than likely be an accessory itself that's shorting out and grounding its housing??

anthonybradley · 05-06-2009, 11:01 PM

a single faulty accesory switch should not cause this. Have both batteries good negative connections to each other / the engine? There can be several wires fused from teh battery switch, you might want to check if they are 1) 12v accessory socket (on radio panel), 2) elec seat or engine cover lift, 3) auto bilge, 4) smal fuse block tucked way uop under the dash (visable from in the cabin when the pull the panel away in my 216), 5) radio memory, 6) trim pump power (although that wouldnt be that small a fuse).
Normally nav lights etc are run of the power from the engine loom, so its worth checking over the engine wiring and breaker etc.

Ants

stereoman405 · 05-07-2009, 02:35 AM

To narrow it down tonight I bypassed the starter, alternator, battery switch, etc. I also removed all fused wires that were hooked up to the battery (which I think are to the power hatch and power seat switches). Basically I jumped a wire straight from the positive battery terminal with the batt switch in the 'Off' position, straight to the lead that is hooked up to the 50A breaker on top of the motor. So essentially the power should be going straight from the battery to the front fuse panel.

When I do this the aforementioned switches light up and no accessories work. I then removed each fuse one at a time, no effect. I then pulled the breaker panel and removed each non-power lead one at a time with the same effect. Except that when I removed the last wire in the series (on an Acc. breaker) the lights shut off, only to turn back on as soon as I turned any accessory switches back on.

I did clean the battery terminals when I installed the Blue Sea setup. How else can I verify the grounds? Do you know where the main ground bus is for the batts and motor? I have a feeling you might have to pull the motor to get to it.

I'm new to this, so can you explain why a ground would cause this? I just assumed it was a positive short into the ground bus, but maybe I've been focussing on the wrong thing here. It seems that the lights would only light up like this if power was back feeding somehow.

Thanks for the help.

Eddie · 05-11-2009, 02:35 PM

The block that was causeing my issue with the lights was the ground block behind the battery. Mine has a small 12 guage wire that runs from the battery to that block (the issue), to the dash. There are numerous ground wires that run to the back side of dash that all checked good. Also I was getting good readings on my grounds I just happened to find that one wire running from the battery to the ground block behind battery was bad.

As with my issue I would start where you began pulling and reinstalling batteries. If the problam wasn't there before and now it is I would look at what was done between. After all said and done I was the culprit!!! Hope this helps.

stereoman405 · 05-13-2009, 04:58 AM

Thanks all for the help. Turns out I spent waaay too much time making this more difficult for myself.

The short of it, one of my battery grounds was bad (solved the starting on bank #1 issue). I also discovered that all the grounds seemed to be at either "9 o'clock" or "3 o'clock" on the bell housing. I cleaned all of them up and ran a new 10gauge run to the mini ground bus behind the port battery, and voila, it fixed my issue.

I still don't understand how exactly a poor ground would cause a back feed like that, but lesson learned and problem solved.

On the plus side, my 8+ hours or pouring over diagrams, testing continuity with my VM, and cleaning terminals and adding dielectric grease everywhere has made me very intimate with the inner workings of this beast.