Complete Power Failure

[BrianGothard]

Good morning,

2001 Ford Expedition

I left the lights on and the battery was dead. I jumped the vehicle and it started right up. When I disconnected the jumper cable, the vehicle died. I reconnected the cable and it will not turn over. No ignition, no cabin lights, no headlights, no horn. I let it charge for a few minutes before I disconnected the cable again. (Battery output is at about 9V right now.)

I have the Owner's Guide with the fuse charts.
All of the fuses under the dash are still good. I can hear a faint, steady, slow (one per second maybe) ticking at the box like a relay but I cannot determine the particular one.
All of the fuses in the Power Distribution Box under the hood are good (Mini and Maxi.)
I removed the Maxi fuse for the "Junction Box Battery Feed" and get 9V across the terminals.
I removed the Maxi fuse for the "Ignition Switch Battery Feed (Run/Start Circuit)" and get NO voltage across the terminals.

I am going to try to find a schematic and continue troubleshooting, but I was hoping someone could shorten my search. I am a computer guy, not a car guy, so electricity doesn't bother me. I just don't know the flow to trace in sequence.

Thanks in advance for your assistance.

Brian

 

[Thermo]

Brian, first things first. Put the battery on a charger and get it up to 12.6 VDC. It is very possible that if you completely drained the battery, you have hurt it internally and it won't ever be useful again. But, give the battery charger a try first. Some battery chargers may oscillate a little bit as it is thinking the leads are shorted together, but let it run. It will adventually put enough of a charge into the battery that it will then go into a normal charge cycle.

From there, disconnect the charger and take a voltage reading across the battery posts as soon as you can. The battery should be reading 12.6 VDC. Anything less and the battery is toast. Now, wait 30 minutes and check the voltage again. If it is not 12.6 VDC at this point, the battery is toast.

If the battery passes both of these checks, now, with the multimeter still connected to the battery and the meter in a spot that you can see it as the motor is being started, start the motor and watch the multimeter. Did it drop to less than 11.0 VDC? If yes, the battery is toast, replace. If it remained above 11.0 VDC, then the motor should have started or you have a second issue.

Let me know and I will get you past this. But, it is sounding like you simply have a really dead battery and it is overloading the electrical system leading to the computers getting too little power and therefore turning the truck off.

 

[BrianGothard]

Thanks Thermo. I hope you are right. I will make sure to charge and test the battery. I agree it may be toast. I will let it charge tonight and get back on it tomorrow morning.

However, what throws me is that I cannot even jump start the vehicle anymore. Admittedly, I am trying to jump an Expedition with a Camry, but it does not even make the dash lights flicker. I have had occasion in the past to do the exact same thing when the last battery went bad, and when I hooked up the cables I got dash lights and radio lights and door ding, etc. I get none of that. The only indication of power I get anywhere is the ticking which turns out to be coming from the Remote Keyless Anti Theft module mounted on the firewall behind the pedals. Maybe this battery is just worse than the last one.

Again, thanks for the advice. I'll post back when I get the battery charged and tested.

 

[Thermo]

Brain, keep in mind that if the battery is really drained, it is going to attempt to pull lots of power to recharge itself. If you are using a cheaper set of jumper cables (say a set with 8 gauge wiring), the current flowing through the jumper cables is going to cause a big voltage loss and when the computer sees the voltage down low, it tries to protect itself. Not to mention you were probably stressing out the electrical system on the Camry as it most likely only has like a 100 amp alternator and if you left it on idle, the alternator was only outputting at best about 60 amps (30 amps or so was being used up by the car itself). So, that wasn't leaving a lot of extra power for your truck.

You want to see this effect at work, spend some money and get some 4 gauge battery cables and then use your truck to jump start a small car (don't forget to manually raise the engine RPMs up to about 1500-2000). I bet the person will get out of there car asking what the hell you are doing to their car as they have never had their car turn over as fast as it was. This is where your 130 amp alternator, at a point that it can actually output 130 amps, along with some jumper cables that can transfer that kind of power efficiently, makes a big difference.