1997 E150 5.4L E4OD RWD
Last week I used my van, came home and parked it. It was running great, all gauges were perfect, oil, alt, batt, temp. Next day I went to start it and heard one single faint click. After that I had nothing, no dash lights, no radio, no headlights, no horn, no power anywhere. I checked the battery, continuity checked fuses and relays, looked for loose connections, replaced the starter solenoid on the fender with no change in the problem, checked for loose shifter out of position (had that fixed 1 year ago), and swapped several relays back and forth in the Power Distribution Box under the hood. I found nothing bad. When I disconnect the battery for a little while and reconnect it the power will sometimes come back on, at least until I turn the key, and then "click" and dead.
My next target is ground straps, the starter, the ignition switch, and then the neutral starting switch on the transmission (I think they replaced that when they fixed the loose shifter problem).
Where else should I look to find out why I have no power, no dash lights, etc? What could cause a total loss of electrical power with one turn of a key? Can the ignition switch or the key lock cylinder cause a no power situation? Can it be the starter? I'm going to pull the starter tomorrow and bench test it.
I need help!

 

This could be a very minor problem.

Start with removing the battery cables from the battery. Clean with wire brush or sandpaper and reinstall. See if starter works now..
If it does, good. If it does not work yet, clean where the battery cables attach to the rest of the vehicle.

Battery cable connections at the battery can look good and yet not be electrically clean.
Common problem
Part of regular maintenance..
Let us know how you make out,thanks.

 

That was the 1st thing I did. Checked and cleaned the battery cables at the battery, and charged it overnight. It was 12.3v when the problem occurred and 12.9 after charging. I'm going to check the other end of the cable connections and try to jump-test the starter before pulling it out.
What about the ignition switch on the column under the dash?

 

It is not the easiest test to do, but if you use a jumper wire that goes from the small terminal on the starter and touch the other end to battery positive the solenoid on the starter should attempt to crank the engine , does it ?
A safety step always make sure the trans is in park position. If you get the starter to crank the engine and have the key on, the engine will START !

 

You said whole van no power, so don't worry about the starter yet, you need to restore power first.
I'd test your grounds first, especially where your battery ground cable is terminated.
You test the resistance against your battery ground terminal: Ohmmeter set to 200Ω, red to battery ground post, black to the Gxxx shown below, randomly pick a few, additionally pick another point on the engine block, if you get 5ohm or less, then your ground is fine. If not, red to one of the Gxxx, and black to another Gxxx, check and see what you get.

 

Using resistance testing to verify Good connections is not reliable..

If there is only one strand of wire, it will read continuity and yet not be able to carry the current required.

The correct way to check a connection or circuit is with VOLTAGE DROP TESTS which require the circuit to be under load.

There are several videos explaining the procedure.
Most "mechanics" don't know how to do voltage drop testing. DO IT RIGHT AND DO IT ONCE !

 

Thank you Heiko for these diagrams and information. It will be very helpful with some of the electrical problems I've been chasing for years.
As far as my current (pun intended) problem, Hanky hit the nail on the head with his first suggestion of the battery connections. I removed and cleaned the battery terminals and it seemed to make no difference. As I checked all the other things, they were fine, which kept leading me back to the battery. It turns out that even though the battery was good and the connections were clean, I kept testing for battery power on the + and - lugs and not on the actual battery ends clamped around the lugs. They were replacements that had the cable end held under a clamp (pic attached). Over the years a screw came loose, still making enough contact to hold the cable in place and register on the multimeter but not enough contact to allow the full voltage to pass through to the solenoid and starter. It was only by chance when I took the cables off once again that I noticed the one loose screw. I replaced both with new terminals, for now, and the problem is solved. I'll replace both with new battery cables when I get the time to measure length and wire gauge.
Many thanks to both HANKY and HEIKO for their help.

 

Thank you for the update AND your kind words.

Circumstances can dictate what we do and the situation here is no different.

Those clamp type battery terminals are considered for emergency repair and folks install them and forget them and they do corrode.

I realize it is a 1997vehicle,but the better thing to do is replace the cable with the proper ends on it.
The way things go, the problem will return at the worst possible time.. Cold, wet and night time. Who needs that. Been there . Please consider fixing it right,thanks.

 

Totally agree. That's my plan ASAP as I said in my previous message. If someone can tell me where to find the length and gauge of the battery cables on this particular vehicle I'd appreciate it. I've checked two different service manuals, Haynes and Chilton's(?), the owners manual, and online, and asked at the local AutoZone. I can't find the specs. I guess I'll have to wait until I can actually measure the length and thickness.
Thanks again.