This kit will easily adapt your OEM wires to work with Eva 0-4000RPM Electronic Tach R5503 on '91.5, '92 and '93 Dodge Cummins.
Not sure if your truck is a 91.5? If your truck has a FACTORY intercooler, it is a 91.5 truck.
The factory plug is found under your dash next to the steering column, this allows you to plug into that harness.
Comes with everything shown.
Isspro part number: R8912-92