2006 Dodge Cummins electrical problem

artie · #1 10-13-2012, 12:32 PM

When I start my 2006 dodge 3/4 ton diesel the volt meter on the dash goes from charge to discharge back and forth until it finally settles on charge. But the other day driving down the road it was going from charge to discharge. I cleaned up the battery posts, wires and voltage regulater posts and wires still same problem. I took it to auto value village and the young fellow load tested the batteries and told me I have one dead battery and alternator problems. Driving home I started to wonder so I disconnected both batteries and they both tested 14.5 volts. Turned on lights and other electrical and it stayed at 14.5 volts so I do not think alternator. Before I change what might be a perfectly good alternator does anyone have any ideas? thanks artie

Canadiandiesel · #2 10-13-2012, 01:11 PM

The charge discharge when you first start your truck is the grid heater cycling, even after the engine is running it does this for a couple times to make sure the intake air temp is at the right temperature for easier running,

Sousa like a alternator problem and your batteries should not be sitting at 14.5v when disconnected they should stay at 12.5v there is also a couple people that have had issues with the in-between battery cable, even though the ends are cleaned up there is corrosion in the middle of the cable which is creating a higher resistance and the alt reads that,

I would first replace that in-between cable first and see what happens

Beaver commander · #3 10-13-2012, 01:12 PM

I had a problem like that in my 07 and it was the batteries changed them and no problem since. I picked up batteries at peavey mart for like $100 a pieces. Good luck

artie · #4 10-13-2012, 01:21 PM

Quote:

Originally Posted by Canadiandiesel

The charge discharge when you first start your truck is the grid heater cycling, even after the engine is running it does this for a couple times to make sure the intake air temp is at the right temperature for easier running,

Sousa like a alternator problem and your batteries should not be sitting at 14.5v when disconnected they should stay at 12.5v there is also a couple people that have had issues with the in-between battery cable, even though the ends are cleaned up there is corrosion in the middle of the cable which is creating a higher resistance and the alt reads that,

I would first replace that in-between cable first and see what happens

Yes you are correct I checked both batteries after sitting for awhile and they both read 12.73 volts. If as you explained it is normal at startup to switch back and forth I will just have to watch what happens when running down the road. thanks

Canadiandiesel · #5 10-13-2012, 01:27 PM

It's stupid that it still does that after the engine is already turning 600rpm but its a safety for not stalling and if you do replace the middle cable replace it with some 0/0 welding cable never have a problem again, I have welding cable for all my batterie cables and grounds

artie · #6 10-22-2012, 01:42 PM

Still have some problems. Was down in the Crowsnest Pass and the warning light came on showing the charging system was discharging. Checked and one battery over heated and acid was steaming out of the top. Took that battery out and it was still hot a couple of hours later. Put two new Napa batteries in and drove back to Calgary and the battery posts are now cold to the touch. Voltage running is at 14.95 volts and when I turn it off battery voltage is at 13 volts. I was wondering if this voltage is too high and I need to change the alternator. I would not like to wreck the new batteries.
thanks artie

bb356 · #7 10-22-2012, 02:19 PM

Change the alternator !!!

sunsetrider2011 · #8 10-22-2012, 02:57 PM

Change the altenator,,common problem with dodge deisels

Mr Hawken · #9 10-22-2012, 04:22 PM

its not the alt what happens is that the battery cables were not tight enough and the alt reads battery volts on 1 battery.because the cables were loose is shows low voltage and the pcm tells alt to charge and the alt overcharges the batteries causing the 1 that is charged to overcharge.i have seen this alot when i used to work for dodge.the battery that is boiling over is most likely finished.make sure all cables are tight and wont turn.i have seen them loose right from new.the fact that the voltage guage goes up and down is normal.that is the preheater working and this will do this even after the engine is running.1 thing to note almost everthing will throw a code and the eng light will come on.if the alt is not charging it will throw a code.

santechdiesel · #10 10-22-2012, 04:25 PM

Check the drivers battery positive clamp bolt, physically remove the bolt and clean it, the alternator charges the passenger battery which is connected to the drivers clamp bolt, the clamp bolt is of a smaller diameter than the clamp hole so corrosion can build up causing excessive resistance between the bolt and clamp body. Seen this many times. Also could be the alternator. Best way to confirm is using voltage drop tests when the concern is present. The resistance will cause a voltage drop. Also a full load alternator amperage/voltage output test would be advisable.

ManitobaSlim · #11 10-22-2012, 05:04 PM

I use the cummins forum whenever i have any questions about my dodge. Just do a search of some keywords of your problem and there are always tons of solutions. http://www.cumminsforum.com/

farmhunter · #12 10-22-2012, 11:15 PM

I agree with the tightening of batteries, the alternator senses voltage off one battery and the pcm reads the other, when cables get corroded or oxide on them, you either over charge one battery and undercharge the other, low voltage on the passenger battery can melt/damage your grid heater relay. Clean, Clean, Clean! I haven't seen huge alternator issues, and i work on them every day...

artie · #13 10-23-2012, 07:07 AM

Well I changed the alternator, it has two new batteries, took the battery clamp bolts out and cleaned them they were very coroded, tightened the heck out of all cable connectors and I am still running at 14.96 volts. Most of the cables look coroded so I will change the battery interconect cable as suggested next. I also read on the net of people having their voltage go up to 18 volts and this was caused by an internal regulator in the ECU. I am wondering if I just leave it at 14.96 volts if it might be O.K.
Thanks guys for all the good suggestions as I am new to diesels and dual batteries. I will keep my eye on corrosion and keeping battery cable clamps tight.

santechdiesel · #14 10-23-2012, 07:28 AM

The truck might charge at 14.96 volts for the first bit while the grid heaters are active, they can pull ALOT of amperage. Warm the truck up go for a drive and re-check. You probably repaired the concern by cleaning the severely corroded clamp bolts. Just my two cents.

ccmckee · #15 10-23-2012, 09:03 PM

The grid heaters draw 90A each, there are 2, so yes they will draw down your voltage at start up. Once you hit 20 mph they will turn off no matter what the intake air temp is. All perfectly normal operations. The grids cycling after start up is to reduce the white smoke a cold diesel produces until it is warm.