The paper insulator prevents the hot side from shorting to the plate; the steel washer on the ground side helps it connect to the plate, but I also moved my dedicated ground wire to the voltmeter stud.
This diagram shows the new R wire going to the ig.sw., but it's effectively the same as what's shown above (C223).
See also:
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https://www.fleet.ford.com/truckbbas/non-html/1997/c37_39_p.pdf 
![voltmeter20.jpg The paper insulator prevents the hot side from shorting to the plate; the steel washer on the ground side helps it connect to the plate, but I also moved my dedicated ground wire to the voltmeter stud.
This diagram shows the new R wire going to the ig.sw., but it's effectively the same as what's shown above (C223).
[url=http://www.supermotors.net/registry/media/843356][img]http://www.supermotors.net/getfile/843356/thumbnail/wiringdiagrameb3g.jpg[/img][/url]
See also:
[url=http://www.supermotors.net/registry/media/870470][img]http://www.supermotors.net/getfile/870470/thumbnail/3gswap.jpg[/img][/url] . [url=http://www.supermotors.net/registry/media/843907][img]http://www.supermotors.net/getfile/843907/thumbnail/alternator3gvr.jpg[/img][/url] . [url=http://www.supermotors.net/registry/media/849725][img]http://www.supermotors.net/getfile/849725/thumbnail/fusesblades.jpg[/img][/url] . [url=http://www.supermotors.net/registry/media/830776][img]http://www.supermotors.net/getfile/830776/thumbnail/fusiblelinkrepair.jpg[/img][/url] . [url=http://www.supermotors.net/registry/media/832986][img]http://www.supermotors.net/getfile/832986/thumbnail/bulbsfuseswire.jpg[/img][/url]
https://www.fleet.ford.com/truckbbas/non-html/1997/c37_39_p.pdf](https://www.supermotors.net/getfile/910358/fullsize/voltmeter20.jpg)