I just replace the harness that runs from the headlight to under the dash. I have a 91si hatch and the harness i replaced it with is off a 88-89 rex, everything works right but the only thing wrong is the cluster lights wont turn on is there any way to rewire or should i just get a 88-89 si cluster..Thanksss

 

Here are both the pinouts. Figure out if there are any differences, and rewire.

http://crxcommunity.com/viewtopic.php?t=6184
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/88-89-crx-hf-cluster-wire-diagram-2286204/

 

Are you sure it's a gauge cluster problem? You've already checked the bulbs and the headlamp combination switch?

Also '88-89 tachometer gauge clusters are not all the same. There are some differences in wiring depending on year, trim level, and whether or not the cluster was manufactured by Nippon Seiki or Nippon Denso.