Charging issues Battery went dead due to dome light being left on. after jumping it using another vehicle a reduced power light came on an the hummer wouldnt rev past 1500 2000 rpms. ran like **** and wouldnt come out of it. I took the battery off an put it on charge and it ran fine for a month or so. Sometimes I'd go out and it would start up just fine and sometimes it'd be dead and I'd have to jump it with a jump pack. Sometimes I'd be driving and it'd throw the reduced power code and wouldnt let me drive more than 25 or so miles an hour. alternator has been checked battery changed twice. It has been in and out of the dealership 3 times with nothing found wrong. No draw what so ever. Any suggestions

All systems should reset after disconnecting and reconnecting a good charged battery. However, before going any further you should remove the dead battery, have it checked and either replace it or charge it out of the vehicle. Then, install it and see if that works. If not, you probably will have to replace the BCM. Jump starting a dead battery is a very bad idea unless it is done very carefully, and even then, it can cause damage to modules.

the battery is dead, you know that. (and may be bad)
why, is the only issue.
if lucky just its no good, now, the love to go totally dead after being
totally discharged, like that.
we use charger to see if it has hope, if not a new battery now.
when started was the charge /battery lamp off?
why not take the battery to walfart and exhange it. for new.
take it home and now it starts.
then see if the battery works and holds charge,
charge lamp in cluster out.
or use voltmeter see 13.3. to 15vdc, normal alternator power.
a bad battery (shorted) can cause the altenator to shut down
so, only good battery there is best practices, or go crazy.
right now,im trying to bet my boat trolling battery back to life.
but is hopeless......

if you had a battery charger in your shop
you;'d already know, battery good/bad.

try closing and locking all the doors then unlock the drivers door with the key

Seems to be having problems with the alternator. Alternator itself can be bad, but also the voltage regulator, which sits inside the PCM (powertrain control module).
Don´t continue using with battery voltage around the 10V, because it will ruin your battery as well. Completely charge the battery with an external battery charger and let the alternator be checked out first.

Hello, The Ford systems are real sensitive to Battery fluctuations. You need a fully charged battery to start out with. If the battery is too low and the jump is removed, the car can stop charging.

Ford also made it to reduce the Voltage to the starter. If the battery is low, the Antitheft will reduce the battery voltage to 7 Volts or less.

There are also Relays in the Powerbox. The Ignition Relay may be bad. I understand that the Horn Relay is the same part and if you check the part numbers on the Relays you may be able to use the Horn Relay to get home.

A fully charged battery wil show 13.2-13.6 Volts. All of the Ford, Mercury, and Lincoln vehicles can malfunction like this, so it just isn't your individual car. Your Battery is 5 years old and anything can happen.

I hope my solution is very helpful to you.

this sound to me like at first I thought it was a fuse, as the problem went on it shifted more toward a weak cell in the battery, if a weak cell sits for a little while the battery will not hold the charge in that cell and that will cause loss of power, "its charge", in tne other cells. you had mentioned you used another battery and it ran great but when the battery was removed, things went wrong. You may check to see if there is water in your battery

you will need to have the battery replaced so you are working with a full charged battery

If some internal light "went out" but the switch is still "on", that might do it.
Something could be shorted. Check power seats' wiring. Radio.

perhaps your problem is not so complicated. maybe one of your vanity mirror lights arent shutting off or something. go out in your car at night and look for light after your dome light shuts off.