Hello. I'm usually in the 99-03 7.3 forum. I'm working on a family member's 1992 E350 RV with the gas 460 motor. Lately it has developed a no start issue. I turn the key hear an instant click and ALL power shuts off for several minutes as if both batteries have been disconnected. After 15 minutes or so whatever anomaly has occurred will fix itself and power is restored to the van, gauge cluster, dome light, radio ect. Initially I thought this was a battery issue but I'm convinced there is another issue at hand. The batteries are always connected to a battery tender, voltage is good and when the van does start up cranking is strong. After several hours of tinkering I've found that if I disconnect the ground for the driver's side battery the anomaly will reset. I've tested this several times with someone in the cab and me at the front. Turn the key click all power is off, driver's battery ground cable disconnect/reconnect power is back on.

Here are my question's: Where does battery power connect to the van? Is there some sort of breaker between the batteries and the van that is malfunctioning? Could this issue be the voltage regulator in the alternator?
Other than this issue the van is in good running order

 

You have a bad connection that is breaking under load. You'll have to get your tester out and Start backtracking from the battery with a load on it. Will be tough if the problem is intermittent. There is one lead that goes to the distribution box right near the battery on the vans. Starter has a separate lead. Generally if you lose connection to the starter and accessories, it is your battery terminals. I think the RV should be the same. Have you taken off your cables and cleaned the posted and connectors real good and checked that the main cable isn't corroded and losing contact? Also check the body ground right there at the battery and the motor/frame ground to make sure the connections are good. You may need to take a wire brush to areas to get a good connection. Good luck.

 

2 things to I'd check first; the starting solenoid and the inertia switch. I've had solenoids that went bad and stuck and I've heard of inertia switches that heated up under load and quit only to start working again when they cool down. If not there, I'd do as Spaznaut suggests and start at the beginning. Let us know how you make out.

 

I have had this before, and I agree - you have a bad connection that seems fine until you put the load of the starter on it. Then everything dies.

I had one of those "clamp on" battery terminals on the wire that goes from the battery to the starter solenoid. It ended up being heavily corroded inside the clamp area where it could not be seen. I had the exact same symptoms. I replaced the entire cable (it's only like 1 foot long) with one that had permanent, molded-on connections. Fixed the problem.

Could be a bad starter solenoid also. But my bet is bad connection at the battery or at the solenoid terminal.