Truck chargering @ 16.3 Volts

steve812 said
Lars, I'm new to the board but not Mopar. Here's some of my thoughts.

1. Make sure both ends of the battery cables are squeeky clean and tight that also includes and "extra" leads like the one that goes to the radiator support.

Cables are good, I checked them with the DMM and they measure out fine.

steve812 said
2. On your year truck you have 2 small gauge wires going to the back of the alternator...one is Red and the other is Green or Blue?
The Red wire gets 12volts with the key "on"..you can test there for voltage while wiggling the wire. High heat can make these wires brittle and the copper strands inside the insulation may break. If any break than you can develop problems. The Green or Blue wire goes to the voltage regulator, this line grounds out the field in the alternator to induce charging. The Green wire can also get damaged at the back of the alternator. If in doubt about either of the wire terminals...cut the old off and re-crimp new ones on the wires. Trace the Green wire back from the alternator to the VR and make sure the insulation hasnt melted some where along the way. If it has, you will get intermittent shorts to ground and wacky charging. It is usually run in the harness that runs along the valve cover area. Also the 2 position plug that snaps on to the VR may have spread female sockets in it or heat stressed wires. The connector can be replaced and picked up at any good auto parts store. Again check for 12volts at the red wire on the connector with the key "on" and flexing the wire.

Checked the connector, squeezed down the connections to get good contact. Red wire gets 11.5 volts with the ignition in the "run" position. This doesn't change with my wiggling it and trying to put stress on it.

steve812 said
3. You could have bad brushes or sticky brushes in the alternator that will cause charging problems.

Replaced the alternator with a spare rebuilt I had.

steve812 said
4. Make sure the VR is well grounded to the firewall. The VR electronics get their ground thru the outer case and the mounting screws.

Hooked the DMM up to the negative lead on the battery and the positive to the VR case. It is grounding properly.

steve812 said
5. With all the voltage/current ups and downs your battery may have gone a bit braindead. If need be, place a load on the battery like turning on the headlights for about 10 minutes or more, disconnect the battery cables and place a trickle charger on the battery overnight.

Doesn't seem to be the case, used two different red tops and the truck acts the same.

steve812 said
6. If the battery cables have replaceable "emergency" type clamps on them, they can cause alot of problems as the copper strands in the battery cables oxidize much quicker when exposed to air. If you have a strange type battery cable on the positive side I can help you find a proper replacement.

It has the proper cables, no junk.

steve812 said
7. Check to see if you have a plastic 6 terminal connector near the back of the passanger valve cover, if so, pull this apart, inspect and clean.

Truck doesn't have one.

steve812 said
Let us know how you make out.
Regards-Stevo

Not doing so hot so far, fire the truck up, and once it warms up for about 20 seconds then the voltage starts climbing until I shut it off @ 17+ volts. I also have an 84 2WD Ram and I have measured everything I can think of and they both match on everything. Except the 84 charges @ 14.2V and never goes any higher. I've had 5 different voltage regulators on this truck and have a hard time believing that it is the problem. I pulled the bulkhead apart, and everything looks good. The only real thing I can think of is a few months ago the emergency brake light wiring grounded out due to a faulty ignition switch. This in turn burned up the wire connecting to the switch on the pedal bracket, now I have clipped this wire out of the harness and can't find any related damage. Thanks for the help so far.