Cummins Diesel Forum banner

Intermittent charging

3445 Views 5 Replies 6 Participants Last post by  lpennock
I was driving around last night and and heard a ding and got the check gauges light. Sure enough my voltage gauge was reading zero. I tried to make it home but to no avail, so I pulled over and got a buddy to come give me boost. I figured at this point the alternator is probably shot and I'll get a boost enough to get me home.

Anyways when I got a boost from buddy's car and got on my way. I looked down at the gauge after the truck started and it's showing 14 volts and stayed there for a couple mins before dropping to 12 or so. It stayed at the 12 mark until I got home.

Ever hear of this happening? I will check all connections but doubt that it would just suddenly charge if it was a bad connection. Would a bad alternator have these symptoms or a bad voltage regulator?
1 - 6 of 6 Posts
Do the simple clean your terminals n post make sure yu have a good good connections
Than test yur alternator output 13.5V + is good
Hope this helps let me know what happens.
I'd say batteries. Today's alternators need a good sense voltage to charge. But like above mentioned check all connections, check batteries, and alternator
Not derail the thread but mine was charging high so i load tested my batteries and one was total junk so i replaced both last week since they were original. In the morning when i go out to start the gauge shows it charging just over 12. Then when i get in to leave ten or fifteen minutes later it shows charging way high like fifteen or sixteen volts.
If your having charging issues, check the crossover cable and the grounds for corrosion under the plastic insulation, this will cause this issue. It will also cause overcharging of the passenger side battery. The charging is read by the ecm, not a voltage regulator and it will read wrong when the crossover cable is not allowing the charging current to go to the driver side battery.
Also check the temp sensor under the passenger battery. The computer reads the temperature of the battery to regulate the charge rate.
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.