All Electric Is Out

[Expeditiondude]

Got home tonight, my 1998 expedition had been running fine. Turned it off to switch drivers, not even off for three minutes. Next driver tried to start it, and nothing. No interior lights, no alarm, no power locks, no mirror lights under the passenger side visor. Wow!

Called roadside assistance to have the battery checked. When he hooked up the red 12 Volt box thing, we got interior lights and all that, went to turn the ignition, and it all shut down again. After that, nothing happened. Guy told us the battery was at 75% charge. Battery is about 10 months old. Roadside guy said it was not the alternator.

Any ideas on what I should be looking for here?

 

[stamp11127]

Welcome to the site.
You can't condemn the alternator without checking the output - which hasn't been done so far. Also the battery should have been at 100% state of charge in a working system. Since yours is down to 75% there may be a charging or connector issue. A 75% charge is 12.4 volts, low enough to have the alternator turn on to charge the battery.
You will need a multimeter to diagnose your problem since it is electrical. Let us know if you want to proceed or if you will have a shop check it.

 

[Expeditiondude]

Thank you stamp11127.

I've had an alternator go out on a car before, and I still had radio and lights, etc. I'm inclined to believe that there is a connector issue. Is there something obvious I should be look for, aside from say, the positive or negative battery cable isn't connected to the battery?

Also, 6 weeks ago, I had the 8 spark plugs and wires replaced because the check engine light indicated a misfire on #6. Is there any way this issue is related to the plugs?

 

[stamp11127]

Heavy amounts of corrosion on the battery posts/terminals. Beyond that you will need the multimeter.
The spark plugs are on a branch circuit, you have lost the main feed so that isn't the problem.
You can get a cheapy meter or a decent one with safety features that will run around $75+. If you get a cheapy, only use it on the lower voltages - not on your house electric.