Cluster ground plug in

[Denver9]

Attached is a picture of the printed wire cluster harness on my 74 Chevy C20 pickup. Can anyone please tell me WHERE the ground plugs into the printed wiring harness? Sorry for the crummy picture. I hope you can use it.
- Denver9

[hatzie]

Originally Posted by Denver9

Attached is a picture of the printed wire cluster harness on my 74 Chevy C20 pickup. Can anyone please tell me WHERE the ground plugs into the printed wiring harness? Sorry for the crummy picture. I hope you can use it.
- Denver9

That's the printed circuit not a harness.

That being said... There are several grounds on the instrument panel plug.
The GM wiring manual for your 1974 will show the pinout. Look in my signature for the manuals.

The other end of the ground wires is a ring terminal on the kick panel above the parking brake pedal.

[Denver9]

There is what appears to be a flexible ground strap in the cable (harness) that comes from the firewall connector and plugs into the printed wiring on the instrument panel. I would like to know WHERE it plugs into the printed wiring. BTW: I respectively submit that the printed wiring IS a harness; it just happens to be a "printed wiring" harness for convenience. My vehicle is a 1974 Chevy C20 3/4 ton pickup which I have previously posted. You mentioned that all of the ground wires are hooked to a chassis ground terminal. Is that connection made via the hard wired harness or do I need to somehow run a separate wire from the printed wiring to that aforementioned ground terminal? If I sound a bit confused, I definitely am, and I am seeking help to remove that confusion.
Thank you in advance,
-Denver9

[Corts60]

As mentioned, there are several grounds in the connector that plugs into the printed circuit. Unless someone has been in there cutting wires, just plug in the connector and send it.

[hatzie]

1974 ain't the 1960's. There's no ring terminal on the printed circuit or instrument cluster... if it hasn't been monkeyed with.

The ground wires are black jacketed 16ga copper trailing back into the harness from the cluster plug.
They are spliced to a single larger gauge (12 or 14 IIRC) black wire about 6-8" from the cluster plug. This splice is taped over and bundled into the dash harness.
From the above mentioned splice... that single black wire is bundled into the dash harness and runs from the splice to a ring terminal that's screwed to the kick panel above the parking brake pedal.

[Denver9]

Thank you for that explanation of how the ground wires are handled. I have found the ground connection on the kick panel that you spoke of, thanks. I would stiill like to know the purpose of that flat, flexible, cable or strap eminating from the hard wired harness and terminating in a round shaped flat connector that attaches somewhere on the printed wiring harness with about a 1/4 twist. That connector is a totally different configuration than the lamp sockets. I suspect it terminates in thzt hole just above and to the left of where you see the numbers 331 on the printed wiring harness picture I posted earlier.
Once again, my truck is a 1974 Chevy C20 pickup.
Thanks for any comments that may help.
- Denver9

[ray_mcavoy]

That sounds like you might be describing the fiber optic cable that is used to illuminate the windshield wiper switch ... I believe that was a 73/74 only thing, with 75-up going to a separate bulb for the wiper switch.

Some of the earlier years used a similar fiber optic to illuminate the automatic trans shift indicator on the column. And others used it to illuminate the ash tray.

Anyway, the upper end of that fiber optic cable should be attached to a special socket that that twists (quarter turn) into one of the bulb openings. That special socket should also hold a #194 bulb and be installed into one of the cluster illumination locations ... doesn't matter which one as long as it will reach and is a cluster illumination (not turn signal indicator, high beam indicator, warning light etc.) location.

[hatzie]

Originally Posted by ray_mcavoy

That sounds like you might be describing the fiber optic cable that is used to illuminate the windshield wiper switch ... I believe that was a 73/74 only thing, with 75-up going to a separate bulb for the wiper switch.

Some of the earlier years used a similar fiber optic to illuminate the automatic trans shift indicator on the column. And others used it to illuminate the ash tray.

Anyway, the upper end of that fiber optic cable should be attached to a special socket that that twists (quarter turn) into one of the bulb openings. That special socket should also hold a #194 bulb and be installed into one of the cluster illumination locations ... doesn't matter which one as long as it will reach and is a cluster illumination (not turn signal indicator, high beam indicator, warning light etc.) location.

Yup. Sho nuff sounds like the fiber optic illumination.
You can still buy the fiber optic cable with terminators and maybe the lamp socket. The sheet metal holder for the terminators are junkyard scavenger hunt only.