520 h discharges with key off

[1054josh 25]

Ok I've looked with nothing found. So I've got a 96 520 that I've rewired new fuse block new key switch new nine pin connector and new battery. When running it charges like it should but when u turn the key off it will drain the battery dead over night. I'm starting to think this why the nine pin connector was melted and the fuse block was removed. I followed the electrical diagram to rewire it and everything works just like it should. So I'm wondering if its the voltage reg or the stator or possibly something else please help.

[C-160 Auto 10]

Did you have the same problem before you rewired it? How old is the battery? Have you tried disconnecting the battery and hook it back up the next day to see what happens? Sounds like a bad battery or something shorting to ground.

[gwest_ca-(File Mod) 10,481]

Disconnect the negative battery cable. Connect a test light between the negative post and the cable you just disconnected. Light off - no short. Light on - shorted somewhere. Unplug one item at a time and reconnect until the light goes out. Short found.

 

Garry

[1054josh 25]

New battery and when I connect a light between battery neg and the disconnected ground wire the light lights. I know that old trick and use it on almost everything I change a battery in just to check because you never know. The only way the light goes out is if I unplug the key switch or disconnect the center terminal on the voltage reg. And as far as the Onan running before I fixed all the little issues that wasn't happening cuz didn't want to take a chance in hurting any of the electrical components. The guy I got it from told me he had it wired with a toggle switch and a push button for the starter. So between that and all the melted together wires, fuse block, and nine pin connector. I figured I had better fix it all before I even tried to start it. Thanks for the replies

[boovuc 1,090]

Josh,

Is it possible your key switch is bad from the box? Is it a Toro switch? I saw this a few weeks ago on a 314-8 where the switch was for all intended purposes a direct plug in replacement but when the key was off, it still was powering the gauges which would have run the battery down. Even the numbering on the tabs was the same as the stock switch. A direct Toro replacement switch was the fix.

[gwest_ca-(File Mod) 10,481]

The voltage regulator DC+ output goes to a fuse and then to the battery in the wiring diagrams.

If the regulator is the cause of the drain disconnecting the ignition switch should not affect the drain.

If the ignition switch is the cause of the drain disconnecting the regulator should not affect the drain.

That suggests the regulator DC+ is not wired directly to the battery.

 

None of the ignition switch terminals should be connected with the key off. Can you check with an ohmeter? 

 

Garry

[buckrancher 2,673]

have you tried unpluging the pc board for the alarm lights?

[1054josh 25]

Ok so I've done some more testing and I think I have it narrowed down to the regulator. My question is when I hook the meter to the terminals I can flow current from center b+ to one of the ac side but not the other. Does this mean that the diode is bad on that side or is it supposed to be this way? It charges fine and runs purdy good. Also I have a dead short when I check between the two wires coming from the stator but the are not shorted to ground. Is this right. This first Oman I've owned. Thanks for all help.

[Jeff-C175 7,195]

 

Does this mean that the diode is bad on that side or is it supposed to be this way?

 

I believe that the Onan regulators are pretty much the same as on the Kohler twins... and if so, then from the center to one of the AC terminals is SUPPOSED to be a direct short.  And measuring to the other AC terminal from the DC terminal will tell you nothing that means anything.

 

There are several threads here recently about testing voltage regulators...

 

I have a dead short when I check between the two wires coming from the stator

 

What type of meter are you using for this measurement?  Analog or digital?

[1054josh 25]

I have a digital. I guess I'm not understanding how voltage is keep from flowing back thru the regulator. Because the center terminal b+ is hot all the time and it flows from there thru regulator out the one ac side then thru the stator and back to the other ac side. Hey wait is it possible that maybe the tack is hooked to the wrong side of the regulator? Maybe that is my problem. Ill check that tomorrow night. What do you all think?

[Jeff-C175 7,195]

I haven't looked at the 520 wiring diagram, but I would be surprised that the B+ terminal of the regulator is in fact SUPPOSED TO BE "hot" all the time.  I guess I need to take a look at that diagram.

 

Pretty  much every other diagram I've looked at shows a complete disconnect of the battery when machine is off.

 

But, you still may have a defective regulator...

[Jeff-C175 7,195]

OK, I looked at the wiring diagram and saw for myself that the battery is in fact connected to the B+ of the regulator at all times.  No switch in between.  Kinda weird in my opinion but I guess it worked for all those years so it is what it is.

 

You mentioned the tach being connected to 'the wrong side' of the regulator... schematic shows it connected to the B+ terminal, not one of the side terminals.

[1054josh 25]

Really the schematic that I have in the original owners manual shows it hooked to the ac side but it also only shows two terminals on the reg.so I'm not sure what to do

[gwest_ca-(File Mod) 10,481]

Here are the detailed wiring diagrams from the Demystification Guide

 

Garry