I was able to find this on another forum..but I'm not sure what plugs he's referring to. (Granted, I havent taken the cluster out to look) but I'm guessing there's plugs that go to the back of that harness?
" Here is the info i used to get mine working from a 4 cyl to a v8 worked perfect.
Regardless of whether an Explorer or Ranger cluster is used, a ground wire will need to be reconfigured for the V8 swap. It is the dash harness that determines how the tach reads, not the cluster. In the case of a 4-cylinder dash harness, it needs a ground wire added for the V8 tach calibration; Rangers originally built with a V6 need the ground wire moved from one cluster connector to another to correct for the V8 firing frequency.
Tachometer ground differences for 4, 6 or 8 cylinders
8-cylinder: "Selector" ground configuration:
pin 8 of the 10-pin: (NOT connected to anything)
pin 16 of the 16-pin: (wired to chassis ground)
6-cylinder: "Selector" ground configuration:
pin 8 of the 10-pin: (wired to chassis ground)
pin 16 of the 16-pin: (NOT connected to anything)
4-cylinder: There is no "Selector" ground
pin 8 of the 10-pin: (NOT connected to anything)
pin 16 of the 16-pin: (NOT connected to anything)
The above should be correct for these RBV's:
1996~2003 Ranger/
1996~2003 2-door Explorer Sport
1996~2001 4-door Explorer
2001~2003 Sport Trac "
Welcome Visitor! Please take a few seconds and 
