Battery Measures 15.5 vdc
I don't get you. You are sort of on the right track BUT IT IS ALMOST NEVER THE ACTUAL VOLTAGE REGULATOR that is the problem
IT IS ALMOST ALWAYS voltage drop in the system
OP: HERE IS HOW to measure for voltage drop "and why."
With the engine not running and with the key in "run" Hook your voltmeter to the VR ign terminal. This is same as the "key" side of the ballast resistor. Hook the other probe to the battery POSITIVE post. This will give you a VERY low reading, the lower the better. You very likely will read somewhere around 1 1/2V which is a HIGH reading. What you are reading, there IS the voltage drop FROM the battery, through all the harness, switch, connections, and bulkhead connector...........to the VR. That reading is ADDED to the VR setpoint. That is, IF the VR is "correctly" working at a nominal 14V, and you measure 1.5V in your test, then you can EXPECT the battery to "run" at 15.5
Review the "MAD" article, even if you do not "do" the modification, this article gives a good overview of part of the problem with the harness, as well as a simplified diagram:
Catalog
The diagram gives a good simplified view, although it does not show the ignition switch and "run" (IGN1) wiring.
The functional path is from BATTERY, through FUSE LINK, through BULKHEAD CONNECTOR, AMMETER, WELDED SPLICE, IGNITION SWITCH CONNECTOR, THE SWITCH, OUT THE SWITCH CONNECTOR (on dark blue, "run" IGN1)---------back out through BULKHEAD CONNECOR to the underhood loads and VR
All the capitolized words are points for concern for voltage drop........bad connections..........You must chase them through that path
One way "out" of this is to install a relay to run your underhood loads. Electrically cut the "ignition run" wire coming out of the bulkhead, use the bulkhead end to trigger a relay, fed, say, off the starter relay, and then the relay feeds the underhood end of the cut wire. I say again "that is just one way"
I don't get you. You are sort of on the right track BUT IT IS ALMOST NEVER THE ACTUAL VOLTAGE REGULATOR that is the problem
IT IS ALMOST ALWAYS voltage drop in the system
OP: HERE IS HOW to measure for voltage drop "and why."
With the engine not running and with the key in "run" Hook your voltmeter to the VR ign terminal. This is same as the "key" side of the ballast resistor. Hook the other probe to the battery POSITIVE post. This will give you a VERY low reading, the lower the better. You very likely will read somewhere around 1 1/2V which is a HIGH reading. What you are reading, there IS the voltage drop FROM the battery, through all the harness, switch, connections, and bulkhead connector...........to the VR. That reading is ADDED to the VR setpoint. That is, IF the VR is "correctly" working at a nominal 14V, and you measure 1.5V in your test, then you can EXPECT the battery to "run" at 15.5
Review the "MAD" article, even if you do not "do" the modification, this article gives a good overview of part of the problem with the harness, as well as a simplified diagram:
Catalog
The diagram gives a good simplified view, although it does not show the ignition switch and "run" (IGN1) wiring.
The functional path is from BATTERY, through FUSE LINK, through BULKHEAD CONNECTOR, AMMETER, WELDED SPLICE, IGNITION SWITCH CONNECTOR, THE SWITCH, OUT THE SWITCH CONNECTOR (on dark blue, "run" IGN1)---------back out through BULKHEAD CONNECOR to the underhood loads and VR
All the capitolized words are points for concern for voltage drop........bad connections..........You must chase them through that path
One way "out" of this is to install a relay to run your underhood loads. Electrically cut the "ignition run" wire coming out of the bulkhead, use the bulkhead end to trigger a relay, fed, say, off the starter relay, and then the relay feeds the underhood end of the cut wire. I say again "that is just one way"
