Tach Plug, 92 & 93 trucks
http://www.cumminsforum.com/articles/articles/47/1/Tach-Plug-92--93-trucks/Page1.html
Stan Pacool
By Stan Pacool
Published on 04/3/2007
Hope this is of some help for folks trying to find the stock tach plug.
May also apply to 91.5 and newer as well as the 92 and 93's.
The plug is a small flat plug and is located close to the steering column under the dash. The repair manual calls out "Near the fuse block". I think the plug is grey but can't remember for sure. There are 4 wires going to it -
Black -Ground
orange - Switched 12V
red - switched 12v to signal flasher(don't ask cause I don't know!! )
Gray - tach signal from the PCM
The crankshaft position sensor is where the signal originates and then goes to the PCM and on to the plug. You should be able to check for a reading at the gray wire with a digital meter. My PCM was bad and it took me a year to figure out what was going on. A new PCM solved the problem.
The plug is a small flat plug and is located close to the steering column under the dash. The repair manual calls out "Near the fuse block". I think the plug is grey but can't remember for sure. There are 4 wires going to it -
Black -Ground
orange - Switched 12V
red - switched 12v to signal flasher(don't ask cause I don't know!! )
Gray - tach signal from the PCM
The crankshaft position sensor is where the signal originates and then goes to the PCM and on to the plug. You should be able to check for a reading at the gray wire with a digital meter. My PCM was bad and it took me a year to figure out what was going on. A new PCM solved the problem.