absolutely no power
 

Just went out to start the expedition (2008 EL with about 35000 miles). I got in, the power running board opened, started to turn the key, the power seat started forward, it made one very short noise as if it were going to start, then the power went completely out. It has no lights, no power anything, and it won't even try to start. The battery has a green "eye". Is there some sort of master relay? Worst part is, without electric, I can't get it out of park to drift it forward. HELP!!

Sounds like the battery terminals are corodid or maybe even loose.Check the terminals make sure they are not loose.If they are tight loosen them and then twist the terminals back and forth and see if you get any power.If you get power tight the terminals if this dosent work check the ground wires and make sure they are tight and no rust under them.Thats about all I know to do.

X2 Everyone should at least have a $10 test light, that will help isolate many common problems. At least with it we could guide you thru the simple stuff. Franklin2 should find this post, best I've seen on this forum for electrical issue's.

X3

If not a test light, a $10 digital multimeter from Walmart, Harbor Freight, whereever. Or a secondhand Fluke from a pawn shop. That's more complicated, but it'll tell you the exact battery voltage, or the voltage drop between battery stud and cable. If you don't understand what you're reading, post the numbers to a forum for help. It'll diagnose charging problems better than a light bulb.

foxcoupe, what was the final problem? I encountered the same thing just as you've described tonight on my 2008 expedition. Had just parked it an hour earlier, jumped in it and hit the key to start and as soon as the starter engaged everything went dead. Battery tests at 12.8 volts, the number 55 relay clicks, the headlights are very dim and fade out after couple of seconds of disconnecting and reconnecting the ground cable. I would appreciate any information on the solution to your issue.

it was under warranty, so they towed it to the dealership, and said the battery was dead. The replaced the battery, and no problems since. Interestingly, the tow truck driver jumped it to drive it onto the flatbed towtruck, and it did start, but was almost in limp mode, the power running board would not even close again after he jump started it.

Ron

Foxcoupe,
Thanks for the quick reply. I initially didn't think it was the battery since it showed 12.8 volts on the multi-meter. I jumped it and it fired right up so I made a quick battery change and it fired right up. You saved me a day off work tomorrow and hassling with the dealer to get them to pay for the tow. I've never seen a battery die that quick. Much appreciated!!
~Kelly

Just a reminder; You can't check a battery just sitting there, you have to put a load on it. If you would have held the meter on the terminals while someone else tried to start the vehicle, that would have given you a true reading on the condition of the battery. The battery testers they use at the stores have a large resistor pack inside with cooling holes. They put this resistor pack across the battery while the meter on the front gives you a voltage reading to get a true indicator of the battery condition.