Keffer inc Posted April 17, 2015 Share Posted April 17, 2015 Ok, I replaced my alternator a couple weeks ago, today, a wire burned up inside the alternator and looks like it shorted out. I fixed the alternator and its charging 14 volts again. Now though, the battery should be charging 14 volts but it remains 12.30 volts. The funny thing, If I use my volt tester and put the positive lead on the positive terminal, with the negative lean on the step, I get 14 volts, but if I go only to the battery terminals, only 12.30. gauge in cluster reads 12 volts. Anyone know whats up? Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/ Share on other sites More sharing options...
RedBullDog Posted April 17, 2015 Share Posted April 17, 2015 Bad cell in a battery probably 1 Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-286939 Share on other sites More sharing options...
Keffer inc Posted April 17, 2015 Author Share Posted April 17, 2015 Left it sit over night, still had 12.20 volts with the truck off, which is normal. I'm about to drive it to a shop to get the pinion seals replaced and hopefully it will bounce back to normal. I hope its not the batteries, I'm going disconnect them when I get home and see if any of them are draining down. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-286953 Share on other sites More sharing options...
Dirtymilkman Posted April 17, 2015 Share Posted April 17, 2015 Id do voltage drop tests on the cables too but a battery with 12 volts is usually junk Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-286968 Share on other sites More sharing options...
41chevy Posted April 17, 2015 Share Posted April 17, 2015 After the Voltage drop check, est each battery cell with a Hydrometer. That will give you the condition of each battery cell. Pick up a hydrometer a Napa, Auto Zone or even Wally World for under 10 bucks. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-286994 Share on other sites More sharing options...
Keffer inc Posted April 18, 2015 Author Share Posted April 18, 2015 Anyone know what is up on the firewall next to the starter solenoid? One of my studs are broke inside that black box. The box has two ground cables going to it (Think the're ground anyways because volt meter doesn't show and volts) ((I think its a ground circuit breaker)) I used the truck all day yesterday and today, with the head lights on. It worked right until I turned it off for fuel (no starting issues prior) and then it would only crank for the first couple seconds... then it finally fired. checked my cam position sensor plug but that wasn't the reason.. so I don't know, No electronic malfunction codes. Now that I'm home for the weekend, I'm about to disconnect the batteries to see if one drains down. Also about to pull my oil filters to check all cables near starter. But depending on what is on the fire wall, that could be my issue.Also, my temp gauge has been spiked up almost into the red, but when I turn the truck off, then "Key On, Truck Off" its in the normal operating spot.I can't find any loose or broken cables anywhere yet.**********EDITED********************** Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287112 Share on other sites More sharing options...
Keffer inc Posted April 18, 2015 Author Share Posted April 18, 2015 Hey Dirtymilkman, how does one perform a voltage drop test in cables? Only thing I know how to do is read voltage. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287116 Share on other sites More sharing options...
6368 Posted April 18, 2015 Share Posted April 18, 2015 , If I use my volt tester and put the positive lead on the positive terminal, with the negative lean on the step, I get 14 volts, but if I go only to the battery terminals, only 12.30. I f i' am understanding you correctly it sounds like you have a problem from your batteries to your ground. check those negative cables especial at the back of the starter Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287119 Share on other sites More sharing options...
Solution Macktech689 Posted April 18, 2015 Solution Share Posted April 18, 2015 That black box is a breaker that protects the vehicle ground system. Replace it and I'm sure your problems will be solved. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287127 Share on other sites More sharing options...
Keffer inc Posted April 18, 2015 Author Share Posted April 18, 2015 Think you're right Macktech689, Took a look at the "three batteries in one box" schematic (which is my truck) and the ground from my alternator goes to frame ground, then to engine ground, then to the ground circuit breaker, then starter and batteries. So I think that would explain my previous statement with the batteries and the step. Thanks for your in-put everyone. Will see if that works monday night when I go to Mack and get the new one put on. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287130 Share on other sites More sharing options...
Macktech689 Posted April 18, 2015 Share Posted April 18, 2015 Just to check it you can bolt the ground cables on the breaker together and see if the batteries are charging, but don't leave it that way get a new breaker. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287131 Share on other sites More sharing options...
Keffer inc Posted April 20, 2015 Author Share Posted April 20, 2015 Tested that box with my positive test lead on the positive battery terminal, and with the negative test lead, tested both grounds from that box, one cable had 12.30ish volts and the next one beside it had 14 volts. Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287272 Share on other sites More sharing options...
Keffer inc Posted April 25, 2015 Author Share Posted April 25, 2015 Just letting ya'll know what's going on. I replaced both the batteries and the ground circuit breaker. All works properly now. Thanks for the help 1 Quote Link to comment https://www.bigmacktrucks.com/topic/39721-i-have-charging-problems-help-please/#findComment-287772 Share on other sites More sharing options...
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