Tachometer Wire

[landonms10]

I have a 91 Sierra that has the moonie gauges in it, obviously with no tach. I recently bought a gauge cluster with the needles, and a tach that came out of a 91. Will it be a clean swap between the two? Or will I have to do something to make the tachometer work?

 

[PlayingWithTBI]

Will it be a clean swap between the two? Or will I have to do something to make the tachometer work?

FWIU you'll need to hook your tach to the white wire coming off the coil.

 

[texas tough]

I mounted my tach on top of the steering column, worked out good. why are u replacing the original gauge cluster display? if its not working its likely a bad solder joint, easy fix. I know they fail alot due to this, because you cannot find one still in a gmt400 in a salvage yard.

 

[landonms10]

I mounted my tach on top of the steering column, worked out good. why are u replacing the original gauge cluster display? if its not working its likely a bad solder joint, easy fix. I know they fail alot due to this, because you cannot find one still in a gmt400 in a salvage yard.

I’ve decided to replace it because I wanted one with the needle gauges and a tach.

 

[DerekTheGreat]

FWIU you'll need to hook your tach to the white wire coming off the coil.

I've heard '91's without the tach are actually wired for them? That the swap from moonies to tach is a direct one for those unicorns? It certainly wasn't like that for the '88 and '89 trucks I converted, had to run the wire like you said and move some wires in the harness around.

 

[Donald Mitchell]

Here's a thread on this. https://www.gmt400.com/threads/89-to-91-instrument-cluster-swap.23804/

 

[landonms10]

I've heard '91's without the tach are actually wired for them? That the swap from moonies to tach is a direct one for those unicorns? It certainly wasn't like that for the '88 and '89 trucks I converted, had to run the wire like you said and move some wires in the harness around.

Yeah, I plugged it in last night, perfect fit and worked.

 

[DerekTheGreat]

Confirmation of what I thought was perhaps a myth. Very cool and good to know.

 

[Danny CainOBS]

@landonms10 nice!! Did you happen to get any pics of your install and looks? Was curious,
Looks like I’ll be playing this same game in the next week. Just won a bid on eBay.