Gauge cluster differences

[krazy_texan]

Ok so I have 2 different trucks my dd is an 86 custom deluxe 10 4x4 with a 4spd the other is a 79 k20 silverado auto trans but it has a factory tach dash the 86 is what I'm going to fix up nice the k20 is going to be my hauler and snow plow how hard wiring wise would it be to put the 79 tach dash in my 86
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[mfwcar11]

not sure on trucks. but on my race cars just a green wire to the distributor,one to Ing, light, grown!!

[JMurray]

I'm kind of in the same boat right now, I have an 82 C10 I put a 87 wiring harness in the dash but still have the 82 gauge cluster, I can't get my gauges to work, I'm assuming the locationg of the contacts on the printed circuit is different I have considered tying to hard wire all the gauges and eliminate the printed circuit.

[ray_mcavoy]

I believe 78 to 87 all have the same pin-out on the cluster plug (except for trucks with the idiot light clusters). But it would be a good idea to double check with 79 & 86 wiring diagrams just to be sure.

It was the earlier years that had some differences in the cluster wiring with ammeters (73-75) instead of voltmeters (76-up) & mechanical oil gauges (73-77) instead of electric oil gauges (78-up).

As for the factory tach wiring, they use a separate 3-wire harness that plugs directly onto the back of the tach. The other ends of the wires go to power (fusebox), ground, and to the "TACH" terminal on the HEI distributor. Just transfer that harness over from the donor truck.

The printed circuit on the back of the cluster will automatically take care of the fuel gauge being re-located to the lower/left corner on the tach cluster. And the auto trans shift indicator just attaches to the cluster with a couple of screws so that's easy to swap.

[rcbildr]

A while back I upgraded the dash in my friend's 83 1-ton (SRW) from lights to gages using the instrument cluster from a 76 or 77 Suburban. Here's the link to my post about that, http://67-72chevytrucks.com/vboard/s...d.php?t=525870, there is some very helpful info that was posted there.

[motornut]

i did it to my 78
the gas gauge wire in the plug has to move
and add a ground for gas
i put the tach power to the pink/black custer power

[Ski-me]

I converted my 89' cluster to a 91' electronic cluster and had to re-pin the connector. Maybe you can see if the 87' and 89' are similar

Hope this helps a little.....

[motornut]

and one for the 78s may help