Short in the ACC pole
Our motorhome 2002 Newmar Mountain Aire, 8.3 cummins has a short in the Accessory side of the ignition circuit. When you replace the fuse, and turn the key to ON- or - Acc, the fuse blows. The ign...
Forum Discussion
Tom,
I have done diagnostics on systems that looked a lot like your situation. I am guessing that the ACC circuit comes out of a gang plug on the ignition switch...
If that is the case, can you identify that wire?
If you can, remove that wire from the gang plug. This is just about always possible, but it is never easy (we seem to be way past easy) and it may take a special tool to release the latches that hold that connector in the plug body. When it is loose, now at least you can power things up and fine out what is not working. That may lead you in the direction you need to go.
Now that the system does not blow the main fuse, it might blow a single fuse for a single part of the ACC system. This could be your bast bet to track down the problem. You can now get things started.
Next cheap, dirty and very effective search method.
Now that the problem circuit is isolated, feed it power through a good sized light bulb. I have a collection of bulbs with wire leads attached but I do this more than most people. When powered up that light should light up - if there is the solid ground you reported.
Now here comes the simple and cheap part. Get a small compass. The current in that wire is creating a magnetic field that you can follow. You won't be able to follow it when it is inside the frame rail, but any place that wire is exposed, you should be able to identify it.
Sorry, I had to put a break in here.
The compass needle will lead you along. Just keep looking for the indication of current flowing, when you no longer get that, the short to ground is behind you.
Please keep us informed what you find or don't. Everything matters.
Matt
I have done diagnostics on systems that looked a lot like your situation. I am guessing that the ACC circuit comes out of a gang plug on the ignition switch...
If that is the case, can you identify that wire?
If you can, remove that wire from the gang plug. This is just about always possible, but it is never easy (we seem to be way past easy) and it may take a special tool to release the latches that hold that connector in the plug body. When it is loose, now at least you can power things up and fine out what is not working. That may lead you in the direction you need to go.
Now that the system does not blow the main fuse, it might blow a single fuse for a single part of the ACC system. This could be your bast bet to track down the problem. You can now get things started.
Next cheap, dirty and very effective search method.
Now that the problem circuit is isolated, feed it power through a good sized light bulb. I have a collection of bulbs with wire leads attached but I do this more than most people. When powered up that light should light up - if there is the solid ground you reported.
Now here comes the simple and cheap part. Get a small compass. The current in that wire is creating a magnetic field that you can follow. You won't be able to follow it when it is inside the frame rail, but any place that wire is exposed, you should be able to identify it.
Sorry, I had to put a break in here.
The compass needle will lead you along. Just keep looking for the indication of current flowing, when you no longer get that, the short to ground is behind you.
Please keep us informed what you find or don't. Everything matters.
Matt
