89-91 tach versus 92-93 tach

[bgilbert]

Thought I'd post a couple part numbers and pics of two OEM/dealer add-on tachs. The first is an early tach for 89-91 and will not work with the 92-93 trucks due to a different plug. It's part number is 56004110. The second is for 92-93 trucks, it's part number is 82400714. Don't buy the wrong one and find out the hard way .

[revemup15]

Cut it off and use butt connectors

[RCCUMMINS89]

Never knew the above, thanks Bill.... come in hand if one were trying to "restore" something.

[RCCUMMINS89]

But now everybody knows bill has at least 2 tachs

[Mark Nixon]

I've mentioned the differences several times.
If you search, you'll even see where I have mentioned it.

In actuality they ARE the same tachs, just the plug is different.
As you can see the connector pins are even the same shape, just the plug housing is different.
Just remove the housing and connect them to the OEM harness the same way Autometer does with theirs.

BTW, the 1989 and MOST 1990 engines DIDN'T come with notches in the damper for the tach to read off of, either.

Mark.

[bgilbert]

I've mentioned the differences several times.
If you search, you'll even see where I have mentioned it.

In actuality they ARE the same tachs, just the plug is different.
As you can see the connector pins are even the same shape, just the plug housing is different.
Just remove the housing and connect them to the OEM harness the same way Autometer does with theirs.

BTW, the 1989 and MOST 1990 engines DIDN'T come with notches in the damper for the tach to read off of, either.

Mark.

Yeah I knew you have been saying it for years Mark, but didn't know if you've ever posted a pic of the two plugs. I thought it would be beneficial for those looking to buy a high dollar tach thinking it will be a plug and play to see what 'plug' to search for.

Philip and I have been thinking the two tachs operated off of different voltages? Has anyone ever done what you suggest, removing the plug and splice it in? revemup15, do you have experience with this? We sure hate to fry or ruin a high dollar piece.

[RCCUMMINS89]

But now everybody knows bill has at least 2 tachs

And doesn't trim his fingernails very often

[Mark Nixon]

Bill, I also have had both tachs side by side, even the wiring color codes are the same.
If you look at the underdash harness, though the early version is a bit more confusing to sort out, it ends up being the same layout, the connectors are just shaped differently.
The early style CPS just doesn't have a low voltage wire added in to tell the ECM there's a problem.

In the early version, the tach plug piggy-backs to something else in the harness, but I forget what it was.

Mark.

[Mark Nixon]

Couple of pics, courtesy of DTR, posted by BobS on 1stgen:

Early under dash wiring shots:




Late under dash harness/pigtail shot:




Mark.

[DodgeFreak]

I had an 89-91 tach in my 92 before i sold the tach, I just made jumper wires for it. Seemed to be right.

[bgilbert]

I had an 89-91 tach in my 92 before i sold the tach, I just made jumper wires for it. Seemed to be right.

Thank you, very good to know.

RC, that was the girlfriend's nails lol.

[RCCUMMINS89]

LOL... well that explains it.

[turboram]

My local dealer said he remembers seeing a nib tach for a first gen on the shelf not long ago.... he is looking for it for me

[apexfd]

Is there a good tach kit for Early trucks?

[rockbuggy4x4]

If one were to put a tach on an early model (89-90) they would need the later dampner? And does anyone know if the under dash plug is there?