what are you guys tapping into to run a tach on these 1st gens?

 

if you run an isspro like this Isspro 4k Tach they run off the dampner via magnet and receiver they work slick too

 

A while ago I looked at the installation instructions for the receiver and magnets. However, for trucks like mine with a cam position sensor at the outside surface of the dampner they would not work. What am I missing?

 

In your '92 CTD, look under the dash, right above the fuse-box, taped to the steering column. There, you'll find a four-wire plug. Connect the 4K ISSPRO tach there. DO NOT use the ISSPRO adapter as it isn't needed.

READ: Let's Screw-Up Your Steering Column With A New Tachometer and Gear Shifter! - Dodge Diesel - Diesel Truck Resource Forums

 

I found the connector. However, the 4 plug wire colors on mine are grey (with blue tracer), black, orange, and black again. No red wire? I wonder if the factory just used a black piece of wire instead of red??

The OEM factory tachometer plug offers the following:

- 18ga Black = +12vdc for gage lights
- 20ga Orange = 12vdc Common
- 18ga Red = Switched +12vdc
- 20ga Grey w/light blue tracer = Tachometer Signal From PCM

I read through that thread completely. Great documentation you did! How has that ISSPRO tach worked out for you since you have had it now for a few years?

 

The tach still works just fine.

I would suggest you skin the insulation of the wires a bit just to see if the outer surface has faded. You may find the colors are there just under the surface.
Else, look at the 1st schematic image of the 3rd post in that thread and check the tach-plug at the top right. You'll notice the plug has a unique shape. Hold your plug like the plug presents in the image to see where what wire is from top to bottom.

 

Ok, I think I just found my answer in this tach install sticky link below at 1stgen.org
It is in fact a black wire but it is listed as the color red in the service manual. Someone just got their wires crossed


1stGen.org • View topic - tach install

 

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