I need to update the instrument cluster on my'87 D100 and would like to replace the inoperative ammeter with a voltmeter. When was the Voltmeter available in the truck line so I know what to look for? I would be willing to replace all the gauges to get the right look. Thanks for any help.

You will also have to bypass the wiring and only get a low amp under the dash so you don't burn up the harness. Do a search on here that discusses the wiring issues.

I've got an OE voltmeter in my '87 D250 BUT...it came with a complete cluster from a 1992 D250 and I think all the gauges are driven by the computer. It was all part of the conversion to 5.2 Magnum, A518, and the complete cooling, heat/AC and wiring systems. It looks stock, using the original gauge bezel but now it has a 'Check Engine' light and other such stuff. I don't know if the voltmeter could be installed in the earlier cluster or used without the computer.