I have a 93XJ with basic instrument, cluster i.e. speedometer fuel gauge an idiot lights. I have found an 87 cluster with full gauge package, is my jeep wired (– wiring harnesses in dash) to accept this full gauge cluster?

 

The wiring isn't the issue, its the gauges and then the sensors. If im not mistaken, you have a drive by wire speedo vs the older drive by cable setup.

commonly referred, gauges will need gauge type sensors vs the dummy light sensors currently in there. Same goes for the speedo.

you'd be best to find the 91+ (if I'm right in referring to old system vs renix being the crossover year for the speedo) gauge cluster with functional gauges and then replace the according sensors for your model year

 

What he said. You want a 91-96 cluster.

 

I have a full gauge cluster that will work for you, I bought it for my 88 that has mechanical speedo so it won't work. PM if interested.

 

It even comes prewarmed and with some oil pressure!