The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - How do the voltmeters work in these trucks?

kipps · 12-30-2018, 08:10 PM

On the battery light, I realized that I don't know if that light was used or not. Most of the bulbs were missing when I got the cluster. The harness was cut six inches from the cluster. That scrap of a harness had a brown wire that ultimately went to the battery light socket.

The second pic shows the backside of the voltmeter when installed. Note that the right pin does not contact the circuit board. For anyone who's putting one together from scratch -- resist the urge to add that connection. It looks possible, but should not be there.

For that matter, it looks like the oil and temp gauges have a similar two/three pin arrangement with a resistor between the two terminals.

The third pic is simply a backside comparison of the '87 and '91 clusters for interest's sake. Note the speedometer connection on the left of that big plastic box. Top to bottom, it's signal, ground, and hot.

One other comment for future reference; these clusters had completely different pinouts. The wire colors were completely consistent, but the position of the wires in the connector were different.

ray_mcavoy, thanks a lot for the help. As I look through some more of these 87 connectors, I'll probably have more questions.

12-30-2018, 08:10 PM	#3
kipps Registered User Join Date: Jul 2014 Location: North-central Virginia Posts: 1,104	Re: How do the voltmeters work in these trucks? On the battery light, I realized that I don't know if that light was used or not. Most of the bulbs were missing when I got the cluster. The harness was cut six inches from the cluster. That scrap of a harness had a brown wire that ultimately went to the battery light socket. The second pic shows the backside of the voltmeter when installed. Note that the right pin does not contact the circuit board. For anyone who's putting one together from scratch -- resist the urge to add that connection. It looks possible, but should not be there. For that matter, it looks like the oil and temp gauges have a similar two/three pin arrangement with a resistor between the two terminals. The third pic is simply a backside comparison of the '87 and '91 clusters for interest's sake. Note the speedometer connection on the left of that big plastic box. Top to bottom, it's signal, ground, and hot. One other comment for future reference; these clusters had completely different pinouts. The wire colors were completely consistent, but the position of the wires in the connector were different. ray_mcavoy, thanks a lot for the help. As I look through some more of these 87 connectors, I'll probably have more questions. Attached Images Last edited by kipps; 12-30-2018 at 08:18 PM.