Need help hooking up gauge cluster with Tach

[1984Silverado4x4]

OK ive gotten it in this far and everything works except the tach which I need your guys help hooking up.

in the pictures theres two sets of wires. I dont know where either goes. would i be able to make connector for one set of wires to hook it up to the distributor?

Or do i have to buy one somewhere?

Which set of wires goes where?

[tvblazer78]

Can anyone help on this? I would like to know about this too.

[BLE 'BURBAN]

White lead to the coil.
Black lead to ground.
Pink lead to ignition "ON" power source.
That other section of wires with the quick disconnect in the middle of it is anybody's guess.

[77gmcjoe]

Originally Posted by BLE 'BURBAN

That other section of wires with the quick disconnect in the middle of it is anybody's guess.

I wondered about that myself.


That cluster is gonna look good in there!

[1984Silverado4x4]

Maybe this picture will help with the other set of wires

[jdmaffeo]

My tach cluster didn't have those extra wires. It might be something that someone added on. Shift light? I dunno...

[BLE 'BURBAN]

Where did you get the cluster? And can you go back to the donor vehicle and trace the wires to their source?

[1984Silverado4x4]

Originally Posted by BLE 'BURBAN

Where did you get the cluster? And can you go back to the donor vehicle and trace the wires to their source?

I found it at the junkyard lying on the floor of a truck that still had its cluster so those are all the wires I can get

[1984Silverado4x4]

Originally Posted by BLE 'BURBAN

White lead to the coil.
Black lead to ground.
Pink lead to ignition "ON" power source.
.

I assume those are all places on the distributor?

[BLE 'BURBAN]

Originally Posted by 1984Silverado4x4

I assume those are all places on the distributor?

Only the white lead goes to the distributor.
The pink goes to your fuse block to a terminal that has power ONLY when the key is turned on. And the black lead just goes to a good ground.

[BLE 'BURBAN]

Here's a thought..... Could this cluster have come out of a truck with a diesel? I've heard that those models with a tach picked up the tach signal from the alternator and perhaps those extra wires on the backside are for that purpose?

[1984Silverado4x4]

Originally Posted by BLE 'BURBAN

Here's a thought..... Could this cluster have come out of a truck with a diesel? I've heard that those models with a tach picked up the tach signal from the alternator and perhaps those extra wires on the backside are for that purpose?

So that means I might have to hook it up to the alternator too?

[77gmcjoe]

Originally Posted by BLE 'BURBAN

Here's a thought..... Could this cluster have come out of a truck with a diesel? I've heard that those models with a tach picked up the tach signal from the alternator and perhaps those extra wires on the backside are for that purpose?

That really doesn't look like any kind of factory harness (the one with the red and yellow wires) to me. I'd say it's something that someone has added, although I really can't imagine what it would be. I believe you're right about diesels getting a tach signal from the alternator, but if it were a diesel cluster, I doubt it would have the harness plugged into the tach that included a coil lead. Also, a diesel would have a lower redline, I would think.

Just my opinion, but I'd ignore the oddball wires. Hook that baby up!

[1984Silverado4x4]

Originally Posted by BLE 'BURBAN

Only the white lead goes to the distributor.
The pink goes to your fuse block to a terminal that has power ONLY when the key is turned on. And the black lead just goes to a good ground.

How Do I hook it to the fuse block?

[BLE 'BURBAN]

Go to your local NAPA auto parts store and ask someone knowledgeable there (manager assit manager, senior salesman for a G.M. FUSE BLOCK IGNITION "ON" TERMINAL LEAD. Part # to follow as soon as I can find my extra ones I have in my tool box.

[boxrodz]

Maybe a picture would help.
The top arrow points out a terminal lead that may be similar to BKE 'BURBA's description. Use this type of terminal to tie the pink wire to the ignition power bank on the fuse box. The second arrow shows the stock location for the pink wire (ignition power) for the tack.

BTW, The black wire can be tied into the 6-terminal Bus Bar Ground located under the dash. The white wire on the stock setup runs to a tach filter before tapping into the distributor. My guess is the tack filter is a RC circuit that filters out unwanted frequencies and voltage spikes. The tack filter may be needed to make the tach operate smoothly/correctly.

[BLE 'BURBAN]

Ok here are the belden part numbers for the fuse block terminal connecters for G.M. vehicles 1977 and newer
BLACK = BATTERY POWER AT ALL TIME PART # 784800 & 784801
CLEAR = POWER ONLY WHILE KEY IS TURNED TO "ON" OR "ACC" PART # 784802 &784803.
Please note that one of each of these part numbers is of a "piggyback" design so you can plug in more than one lead to a given outlet on the fuse block and the other style is just a single lead plug in. Go look at them, detremine which will best suit your need, and put'r ta use dude!

[1984Silverado4x4]

Originally Posted by boxrodz

tack filter may be needed .

I assume you can get one of those from an auto parts store?

[BLE 'BURBAN]

No tach filter needed. The white lead simply runs straight through the firewall and plugs into the tach lead terminal on the distributor cap.

[BLE 'BURBAN]

Here's a pic of the terminal lead you want to get it is NAPA's part number 784803

[xtreme80]

If you can't find a good ground either, that little bolt in the bottom left corner of the fuse box works well. That's where my tach is grounded. And BLE 'BURBAN is correct, there is no filter needed. The distributor has a slot next to the power wire for a tach hookup. You just connect the tach lead to that.

[1984Silverado4x4]

WOOHOO!
It works!

I really appreciate all the great tips and help you guys gave me.

Now does anyone know how I can turn the odometer ahead so the mileage is the same as on my old gauge cluster?

[BLE 'BURBAN]

Originally Posted by 1984Silverado4x4

WOOHOO!
It works!

I really appreciate all the great tips and help you guys gave me.

Now does anyone know how I can turn the odometer ahead so the mileage is the same as on my old gauge cluster?

Easy just unbolt the speedo head from the whole assembly and swap it out with your original speedo head unit.

[1984Silverado4x4]

Originally Posted by BLE 'BURBAN

Easy just unbolt the speedo head from the whole assembly and swap it out with your original speedo head unit.

The original speedo wont fit in the new cluster.

Ive already tried that

[BLE 'BURBAN]

Originally Posted by 1984Silverado4x4

The original speedo wont fit in the new cluster.

Ive already tried that

In that case, disconnect the speedo cable at the transmission end and with a variable speed reversible drill, close the drill down on the INTERNAL cable in the speedo cable. Put the drill in reverse and squeeze the trigger.

Or let me get home and take some pics and I'll show you the fast way to do it.