ignition problem

I had the same problem on a Camaro several years ago. It was a low battery causing the problem. A new battery took care of it.
If your batteries are fully charged, check all the connections. Maybe something is corroded.
Other than that, I have no idea.
Hopefully, it's something simple.

Try the chassis battery disconnect when this happens. Turn it off and then back on. That seems to reset everything when it has happened to me.

Ignitipn switch. They take a pretyy big hit every time you turn to start. Contacts get fried pretty fast.

deeange wrote:
what would be the problem when you turn the key to start all gauges move speedometer pins on 100mph and would not start no cranking just dead all batteries fully charged, any help would be great, thanks

2003 Airstream Land Yacht 30'
workhorse chassis 340hp

sounds like a battery shorting internally or bad battery connections??
like a bad ground ?

Low battery voltage.
Could be battery needs charging or bad connection.
If you have "aux" start try it and see what happens.

Shorted Starter?

tried the aux start same problem, voltage tested 12v on aux. 13v on engine battery, no change on switch.

I think I'd try to isolate the systems b4 guessing what the problem is. First unhook from shore power to make sure I'm not reading converter output on my batts. Then hit the house batt disconnect to get them out of the loop. Then physically remove the negative cable from the chassis batt and let the ECM and stuff reset for a few minutes. Hook the chassis batt back up and try starting.

If there's no change probably have to get out the chassis manual and start chasing circuit gremlins.

If reset doesn't work and all grounds and connections good start looking at ign switch

I'm going to add another thing in the mix...the neutral start switch will give these symptoms...Is trans firmly in park...with fords you could hold up the shift lever and that would close the circuit for the neutral start switch..or shift to neutral and try it...I know you have a workhorse but that switch in Fords ie known to go...possibly your shirt lever is not firmly in park.