i have a 96 with the dummy gauge and i pulled out a full gauge from a friends totaled jeep which is probably a 90 definitely pre 96. is the gauge a direct bolt in or do i need to change some things like how it reads the oil pressure since what i have now is just a light?

 

the 97+ is direct swap... i'm willing to bet that so is -96. besides, it's not a hard job, so it's worth a shot just to find out.
if i remember correctly, my hatch light kept staying on, so i just pulled the bulb out.

 

yes it is a straight swap. the only hard part is getting the ungodly clips off your cluster. putting them back in is easy

 

i thought you also have to change the sensors from the light sensor to the guage sensor...

 

as far as i kno its a pretty straight forward swap. they made the clusters universal . so if you have a base model. you still have wiring for everything else. and vise versa. My Jeep was 2wd. and base model. and now its converted to 4wd 5spd. and all my wires for lights and warnings are in the dash already

 

lights and gauges actually receive the same exact signal.