Voltage problems, cutting out when hot

[Mattax]

Red J1 on the new switch has 12.63 constant (same as battery) with key off and nothing else has power. When key is on yellow S2 and blue J2 had 12.00 volts.
I was just trying to show the voltage differences between the old and new switches, doing nothing else but changing switches. (Even if the voltage readings are still wrong, at least they are moving in the right direction)

Something must be connected.

Everything off (including dome light) and we see maximum battery voltage. It's like an air compressor tank that was filled. We can check the pressure on the tank itself, or we can check at the remote filter. or end of a 100 foot hose. Pressure at the end of the hose is same as the other two locations.

When the key is on, current flows through the ignition points or amplifier, and it is flowing through the voltage regulator - rotor circuit.
Measuring at the middle of the feed for those circuits, the 12 volts you see could be true battery voltage under load. We don't know.

Lets look at this on the schematic used earlier.
Arrow is your meter's red probe.
Voltage at that connection will be battery voltage.

Turn the key to Run.
Current flows through that connector to the switch and then thorugh the rotor, the ECU, and some through the coil.

If the voltmeter black probe is touching a chassis ground, then the voltage at the arrow is battery voltage less any drops due to resistance in the circuit up to the red probe, and any in the ground after the black probe.

We could assume the battery voltage is still 12.6 Volts; and we could assume the ground connections are perfect.
In we case we can conclude there is a 0.6 Volt drop between the battery positive and the probe.
But we don't know that for sure. Better not to assume those things.

One check would be to measure the battery positive to ground under the same condition.
Another check would be to measure voltage drops directly along the flow path.

So if we saw this.

Then we know there's little voltage drop in the wiring up to the connector.

But if this,

Then maybe there is resistance in the wiring, but it could be in the ground connections.

Then measure drops directly.
(If using an analog voltmeter, or your DVM probes don't handle reverse you'll have to put the + probe on the higher voltage location)

.3 V drop under 5 -6 amps isn't great but IMO isn't terrible.

Should get about the same reading at the welded splice.
You can measure that using the alternator output wire as a probe extension because there's no current flowing in it.

 

[RedFish]

Splice these two together or do away with the black wire from the switch altogether?
View attachment 1715376729

I leave the extra black wire alone where it is in the new connector. It dead ends there. Can't cause a issue later.
I put the orange wires together outside/beside the original harness connector. Orange is for the little light at column shift indicator. Floor shift builds wouldn't have it. Factory could have gave it a separate connector. Unused port in the switch connector was a penny saved.
Anyway... black to orange will blow a fuse. Connect orange to orange.
And by the way, the black wires are different gauge/size. Another member had connected his large gauge in harness side to that extra smaller gauge on new switch side. It didn't work.

 

[mopower76]

I’ve now gotten away from the under hood wiring, for now after tracing all wires I’m fairly confident the under hood charging Harness is OK and the problem lies under the dash. I was using my voltmeter to tone test wires from point to point. (I’m sure this isn’t the right way either but it’s what I know.)
When toning wires from bulkhead to ignition switch and from bulkhead to fuse block I figured out that the red wire at the ignition switch J1 would have continuity tone to ground at the fuse box at the bulkhead and at the switch connector.
I can’t find a solid breakdown of the fuse box/block to figure out what fuse is what in each location.
What I have found online doesn’t paint a real clear picture of what goes where and tracing the wiring with the red wire showing continuity at multiple points it is almost impossible to pinpoint where to start.
I’m starting to feel like the seatbelt interlock system cars are different enough that schematics for a regular dart are not the same.
Sorry to jump out of charging into dash harness but I’m positive it is directly related to all of my problems.
Thanks

 

[mopower76]

Just thought I’d send a thank you to everyone that has contributed in this thread.

After further investigation and talking with you guys and other electronics and charging experts I figured out that running the new Denso style hi output alternator with a stock style electronic voltage regulator can be problematic.
I decided to go with a heavy duty fully adjustable voltage regulator from Quick Start.
After installing this system with grounds from the alternator to the voltage regulator and from the battery directly to the alternator case voltage is steady at 14.25 under most all conditions with fans and other accessories running.