I have a low mileage 2005 F-350 CC/LB/DRW 6.0 that has been great so far. I just started having a problem with the batteries running low if the truck sits for a couple of days. The batteries are only 4 months old. I load tested them and they checked ok. I charged them fully, the truck starts fine. Everything works ok, the charging system is working, no apparent problems. If it sits for a couple of days, the voltmeter shows about 8 volts. I decided to do a draw test using an ammeter in series with the negative cable of one of the batteries (I disconnected the other battery for the test). It was showing a current draw of 500ma, which is a half an amp. I know that is way too high and can see from that why they are draining. I disconnected the courtesy lights, radio, and alarm system to eliminate them as possible culprits and the draw was still there. I started pulling fuses and when I pulled the #2 fuse (Instrument cluster), the draw dropped way down to 60 ma. I also heard a relay click when I pulled the fuse. I couldn't find the relay but it sounded high in the dash behind the instrument cluster. I tried to remove the cluster but couldn't disconnect the gearshift indicator cable on the bottom and was afraid of breaking it. Does anyone know how much these trucks normally draw when shut off and has anyone ever run into similar circumstances as this. I'm about at my wits end and thought I would throw it out there. I've done a lot of reading through this site and have learned so much about the 6.0 (my first one) from all of the great people that frequent this site. Any help would be greatly appreciated. Thanks, Joe.

 

Do you have any kind of add-on at all, like a security system or enhanced stereo, or remote start etc.?


And since you obviously know what you're doing, I'll throw something out. There have been a number of complaints about corrosion forming in and beneath the fuse panel in the engine compartment, with problems easily solved once the corrosion is located.

 

Might be worth looking into the fuse panel under the hood. Everything on the truck is stock except for an alarm/remote start. Completely disconnected it to rule it out. Thanks for the reply!

 

20 to 40 Ma.. thats normal parasitic draw...Check alternator..

Dick

 

Thanks, will do.

 

I agree with Dick.....Had one do that one time that every 3rd day battery was dead. Alternator was the culprit. It was grounding to the case internally and drawing down batts but charging with normal voltage.

 

Weather prevented me from checking it today, so I'll know tomorrow. I'm leaning that way as I've virtually eliminated everything else. There's a few different types available for my truck. Any way of knowing which one mine has? If mine has a 110 amp unit, would I be able to replace it with a 140 to play safe?

 

I would get the one it came with..Maybe give the vin to a dealer and he can tell what it came with. Don't just buy one take the big wire off to check..Second thought unplug it all. It may not be the prob.


Dick

 

50 mA is the maximum parasitic draw that should exist, according to spec. But you are reporting 500mA until you pull the fuse to the HEC. That would seem to me to suggest that the problem is in the cluster.

500mA, half an amp, is way too much of a draw and is most likely your problem. Until you eliminate that draw and get back to .050 amp, working with the alternator isn't going to help you.

 

P.S. When you shut the truck off. Or initially re-connect the batteries (like you probably did when you connected your ammeter in line) all of the computer modules come to life. It can take 30 minutes or more for them to all shut down to their minimum draw.

So before you do anything, you should re-do your test. Hook up your ammeter and let the truck sit for an hour and see what the draw is then. Also make sure any interior lights and the hood light are out.

 

Thanks for the reply.I don't intend to buy an alternator until I check it. When I pulled the #2 fuse, the draw cut way back but not far enough....down to about 250ma. However, it would flicker and sometimes drop to between 60 and 100ma. I failed to mention that in my original post (sorry about that). It was unstable. I had left it hooked up over night and it was the same the next day. I pulled and disconnected the cluster just to be sure....same results. i pulled the bulb under the hood and disconnected the courtesy lights. I'll have some more time to play with it today so, hopefully, I'll nail it. Thanks so much for the help. I appreciate it and I'll keep you all informed.

 

Not sure what brake control your running but i had the same thing on my 2003 f250 and it turned out my prodigy brake control was stuck on draining my battery.

 

I have a similar issue, just not as fast to a dead battery. If 50 mA is the maximum per day parasitic draw, then assuming the battery is a fully charge new battery , how many days before the parasitic draw makes the battery incapable of turning the starter?

 

Well, after checking everything under the sun and not finding anything causing the excessive draw, I decided to recheck the batteries. I did another load test, both checked ok. I charged them both up and tried load testing again. This time, one of the batteries came up borderline and I noticed when I put the charger on it, the charge rate was sporadic. I put a couple of new Duralast batteries from Autozone in it and that did the trick. Parasitic draw was down to a steady 65ma and the truck cranked and started fine the next morning. If it ever happens again, I'll know where to start looking! Thanks for everyone's feedback.

 

I just had this happen myself and it was a bad battery also.