could i use the hu off of a 1999 integra into a 1990 intergra if so how would i be able to use it?

 

im not sure about a oem 99 hu, but for my 97, i got a wiring diagram off the internet for a 90-93 hu and all the wires were the same and i think so is the harness. if not you could purchase a 99 wiring harness and splice the wires.