Kyle Kratzer

So the problem began a while back ago when my voltmeter started bouncing all over the place and lights flickered constantly. Finally one day I went to start the truck and nothing. Tried charging batteries, but no luck. They tested bad so I replaced them. The voltmeter then wouldn't get above about 8v and I quickly drained the batteries. I went ahead and replaced the alternator (guy said it tested bad but I don't think he knew what he was doing). Anyway, even with a new alternator I still wasn't getting a charge. I ended up replacing all battery cable ends and wired up an external volt regulator. Then all of the sudden I was getting a charge, but the voltmeter was showing around 16v and the GEN light was on. Last night I disconnected the EVR and hooked up the original harness to see what it would do. Miraculously everything was perfect and I was getting 12.5v not running and about 13.9 running. All day it's consistently ran between 14 and 15 volts, but earlier the lights started flickering along with a pulsating sound that coincides with the lights and the fluctuating voltmeter (still stays between 14 and 15). It did jump up to about 16 volts once and the GEN light came on. Can someone please enlighten me on what's going on. This has thrown me for a loop.
thanks

texasprd

One of the reasons your charging voltage jumped to 16V might have been the alternator being in full-field mode. Try checking the two small wires that go to the field terminals to see if the ground-control one is shorting to ground. One gets positive voltage all the time when the engine is running, the other is the ground-control from the PCM. If the ground-control wire is chafed through somewhere and getting an unintended feed from ground, it will put the alternator in full-field (max output) mode and can kick your charging voltage up to and over 16V. Also, charging voltage is influenced by the battery temperature sensor under the driver-side battery..

When the intake-heater grids kick on and off, it can change the "engine sound" because of the alternator load - that will make the headlight brightness and alternator reading fluctuate. That's usually only right after starting and at low vehicle/engine speeds, and it will usually pull the voltmeter below 12V (though it may be less effect on the voltmeter if the grids are only on for a couple of seconds). You say the voltage is staying between 14 & 15 even when fluctuating, so that doesn't really resemble heater-grid behavior - but maybe something else is putting a major load on the system? Do you have anything non-stock on the truck that could cause a major load?

kherewego@gmail

Hello Thanks .I read your post on charging .Would this be true or the same on 1989 Dodge D250 cumming .I am having same issues over charging ,gong thru voltage regulators & Battery charging 14.9 upto 15 .4 volts .? Thank you for helping me out .

pdhaynie

Try this voltage regulator for your 1989. It will say not available but hit the button that says NEED IT SOONER ? on the lower right.
https://www.summitracing.com/parts/d...dge/model/w250

pdhaynie

The part has a new number and price That is the best regulator out there for a ram by far.