I don't even know where to begin


last year my wife came home with an '03 Eddie Bauer Expedition


when she brought it home the Harmon Kardon system never shut off and drained the battery rather quickly - so I removed it

a few weeks later dead battery, so I replaced the battery did not solve the issue, I consulted Jbrew, we decided it was a wiring issue, I traced every wire, sprayed each cover out with WD40, nothing worked until I changed the batery cable end on the hot side


as of last week it's doing it again, so I replaced the battery and the battery cable on the hot side, nothings working, I can't find anything on the internet except references to the gem module and I can't finda ny water leaks inside the cab...



I've got a new alternator ordered and is in the mail (because my old '79 F-100 did the same thing and it was the alternator)




the alternator will not produce more than 14.6 volts at idle on reved up in gear, when you turn the lights on the volts drop to 12.xx and then come right back up



with either battery cable connected the truck drains the battery overnight



any ideas???

 

hook a tester in line with the negative cable to do a key off drain test. after installing it and with all doors closed and lights off you pull out one fuse at a time. after you pull out the "magic" one your draw will drop down to near zero. this at least gives you the culprit circuit to start tracing out to find your problem instead of killing yourself on the whole truck. any draw above 50mA is too much. the 50mA number is usually what is just required for keep alive memories of radios and ecms. belive me your draw can be anything. ive seen glovebox lights, shorted starters and alternators, ecms, radios, you name it it can be a cause. this is the reason behind only removing 1 fuse at a time. it identifys where to start looking.

 

it's got to be a leak someplace the weather has been ncie the past 3 days and the truck has had no issues so I guess I'll re seal the windshield for starters and then wait for the rain and do the fuse method

 

sun roof draining ok?

 

You're also going to have to "fool" the truck into thinking the doors are closed when they're not, or, you're going to have to sit inside for a long time, 30 mins to an hour to let everything "go quiet" before you start pulling fuses, and, you'll need to have the Ammeter where you can see it from inside. (This is if your fuse box is in the cab like my truck's).

Since the "door open" switch is in the door latch on f150's, I tripped the latch to "closed" with the door open and then came back an hour later with the Ammeter all hooked up during that time and started pulling fuses.

And, I agree with PapaJohn - the parasitic draw on my f150 is 50mA. In addition, at the time I did this I had an Edge Evolution (now a Gryphon) connected which has an additional parasitic draw of 50mA. So, anything much over this is a faulty circuit.

- Jack

 

no sun roof

 

I have noticed a small leak that drips from the grab bars, next to the front driver window upright, when it rains really hard... And today after such a storm I started having electrical issues...

Think I will follow suit and try the patch around the window seal... but I still have the electrical problem... all my accessories, lights, gauges and head lamps stay lit without the key in it....

 

Test your alternator for a drain. I had the same problem on my skid steer last summer, and so I started out this summer by testing everything to find that drain. It turned out to be a short in the alternator.

 

A faulty diode in the alternator will cause a drain and keep the alternator from producing peek current. I have been informed that the diodes usually short out rather than burn out. This allows the current to flow both ways allowing the drain.

The next possibility is a faulty GEM. It controls the Accessory Delay Relay. If the relay remains powered on it will drain the battery.

Pull the GEM. It is a PITA to inspect but most likely the cause of the problem.

.

 

I swapped out the alternator and it solved the issue, same thing as my ol' '79 did



but I resealed the windshield anyway just in case

 

So, might have been the "diode" problem JMC posted?

In the olden days, I could count on a failing battery forcing me to replace the alternator too, in Fords. Or, maybe the alternator killed the battery. I just know they always occurred in "pairs" - which got kind of expensive.

- Jack

 

A bad alternator will definitely kill a battery Jack. Diodes don't have to be "bad" to run too low voltage. They can be varying degrees of "bad" and keep the battery at a low voltage which will clearly shorten it's life. I have had it happen to me twice with GM products (No, I haven't driven Govt. Motors products for many years and have no intention of ever again) The diode trio was easy to change in a GM though.

 

My last post DID sound kind of "stupid", didn't it? :o Of course a bad alternator will kill a battery! *duh*. But, I think I have had to replace at least three alternators due to batteries that reached the end of their life. This was all back in the 70s and 80s, which is when I learned to keep a close eye on battery condition.

One more thing I should add here - an alternator should never be used to "recharge" a dead battery. That's a good way to kill the alternator too. Always use a battery charger for that purpose.

- Jack

 

^^^ agreed