The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

ray_mcavoy · 02-06-2015, 07:49 PM

Pins #1 and #12 on the cluster plug are both for the "BATTERY" gauge (ammeter) and are both hot all the time. It's basically an external shunt type ammeter that simply makes use of the pre-existing charging system wire as it's shunt.

Pin #1 is the "battery side" of the circuit and originally used a black wire with a white stripe. The wire from pin #1 should run out to a 4amp inline fuse that connects to the pre-existing junction block that should be on the passenger side fender near the battery.

Pin #12 is the "alternator side" of the circuit and originally used a black wire. The wire from pin #12 should run out to a second 4amp inline fuse that connects to the pre-existing factory splice inside the wiring harness near the voltage regulator. You'll have to un-tape the harness to look for the spot where 4 red wires are spliced together.

Both of those wires need to pass through the firewall bulkhead connector. This connector uses Packard/Delphi 56-series terminals and the necessary cavities should already be empty on a truck that was originally equipped with warning lights.

The brown wire that you'll be removing from pin #8 of the cluster plug used to operate the "GEN" light and was part of the "trigger" or "exciter" circuit for the alternator. You can just tape this off and leave it unused because the harness also contains a 10Ω resistance wire that will provide the initial excitation current to the alternator.

02-06-2015, 07:49 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,379	Re: Help with cluster swap idiots to full Pins #1 and #12 on the cluster plug are both for the "BATTERY" gauge (ammeter) and are both hot all the time. It's basically an external shunt type ammeter that simply makes use of the pre-existing charging system wire as it's shunt. Pin #1 is the "battery side" of the circuit and originally used a black wire with a white stripe. The wire from pin #1 should run out to a 4amp inline fuse that connects to the pre-existing junction block that should be on the passenger side fender near the battery. Pin #12 is the "alternator side" of the circuit and originally used a black wire. The wire from pin #12 should run out to a second 4amp inline fuse that connects to the pre-existing factory splice inside the wiring harness near the voltage regulator. You'll have to un-tape the harness to look for the spot where 4 red wires are spliced together. Both of those wires need to pass through the firewall bulkhead connector. This connector uses Packard/Delphi 56-series terminals and the necessary cavities should already be empty on a truck that was originally equipped with warning lights. The brown wire that you'll be removing from pin #8 of the cluster plug used to operate the "GEN" light and was part of the "trigger" or "exciter" circuit for the alternator. You can just tape this off and leave it unused because the harness also contains a 10Ω resistance wire that will provide the initial excitation current to the alternator.