Short in the ACC pole

If you have the schematic that shows which items are powered via that fuse
Remove fuse check continuity to ground from that feed to ground,
Now the slow part, one by one disconnect each item until you find the one that makes your continuity short disappear
I suspect that something has failed, something that would automatically have power, not something you are going to manually b operate a switch for,
Unless you have had a rodent chewing on wires, that should be visible unless it chewed a random spot In harness somewhere, creating a short between that hot feed and the ground lead for something else
How long as it been parked

Flute Man wrote:
. Exactly what fuse is blowing?
Jerry
And what size is the fuse? How many amps?

It is labeled " 15 Key SW' and it is a 15 amp

It is in the #1 junction box.

Tom/Barb wrote:

dougrainer wrote:
Lets get clear.
1. You state the IGN system. You mean it does NOT short until you turn the key all the way to engage the starter?
2. The Ign controlled COACH systems including Dash Area(Back up and so on) all work even when the other fuse blows? Doug

The key switch excites both the ACC and the IGN at the same time. when the key is turned to either position, then you turn to IGN and continued to turn to crank.

the fuse blows as soon as either position is reached.

this is why I say there are two discrepancies.

Yes and No. When you turn to IGN(NOT the spring loaded Starter position) it activates Both ACC side and Ign side circuits. BUT, when just going to ACC, that position activates fewer circuits than the IGN side, BUT, will still activate the 1 circuit that blows the fuse. ONE problem, for both sides. Once you find and fix the short, BOTH sides will work and not blow the fuse. Lets wait until you do your ECU testing. So, you refuse to doublecheck the batteries? Doug

Generally, there is only one fault. However by replacing disconnecting and reconnecting all those other things you can accidentally induce another fault. Exactly what fuse is blowing?
Jerry
And what size is the fuse? How many amps?

dougrainer wrote:
Lets get clear.
1. You state the IGN system. You mean it does NOT short until you turn the key all the way to engage the starter?
2. The Ign controlled COACH systems including Dash Area(Back up and so on) all work even when the other fuse blows? Doug

The key switch excites both the ACC and the IGN at the same time. when the key is turned to either position, then you turn to IGN and continued to turn to crank.

the fuse blows as soon as either position is reached.

this is why I say there are two discrepancies.

Lets get clear.
1. You state the IGN system. You mean it does NOT short until you turn the key all the way to engage the starter?
2. The Ign controlled COACH systems including Dash Area(Back up and so on) all work even when the other fuse blows? Doug

dougrainer wrote:
Then see if you have the short? Doug

The ignition switch is out of the system. What is tripping the short is the IGN pole.

The coach system is on a circuit board, all coach systems are routed thru that circuit, That was been changed, no difference.

The Spartan circuits in the coach operate normally, the only thing that is wrong is the IGN system.
all signal lights work, back up camera, all external lights work.

Spartan's skit, shows a direct circuit to the Transmission computer and the ECU, the Transmission computer that has been disconnected. still shows a short.

I'm in process disconnecting ECU.

stay tuned

I am telling you to go at the problem from the Newmar COACH side of the electrical. Have you pulled the Batteries to verify you did not miss a wire or disconnect the smaller gauge wires from both the chassis batteries and the coach batteries. DON'T TELL ME YOU HAVE DONE THAT WHEN YOU HAVE NOT. I have had over 42 years customers swear they have doublechecked after they replaced batteries and they have either a short or a system does not work. They come in and in less than 10 minutes I find the loose wire or POS small gauge wire connected to the negative or a loose wire the batteries were installed on and after awhile, the weight has cause a short. Then they pay me about $100 because they were positive they had done it correctly. On your year, do you have some of the interior ceiling lights that has a 3 position wall switch? When engaged one way the lights are normal brightness and when switched the other way they have 50% dimmer brightness? Did your original Coach batteries, were they 6 volt(making 12 volt) or 12 volt and which do you have now, 6 volt(making 12 volt) or 12 volt. Last, did you do as I suggested and disconnect the small gauge wires both Neg and Pos from the Battery banks and leave just the Heavy duty large Cables connected? Then see if you have the short? Doug

dougrainer wrote:

READ my post again. As I stated, you are(were) looking at the problem from a chassis standpoint. Doug

After removing the entire ACC side of the system. it now becomes clear that the ACC side is not the problem.

next step? Separate one system from the other by Disconnecting the ECU from the engine, see if the short goes away.

working on it. :)

It is not a easy place to get to. To touch the ECU the fuel filter must be removed.
Edit
There is two ECMs for the IGN, side of the Engine system, the Alison / transmittion
The Transmittion is easy , (done) we still have a short.

Flute Man wrote:
Was there any incident just prior to it not working?
Jerry Parr

No, We parked the Coach and now it won't crank, and blows the fuse.