Would someone be good enough to explain the differences between the harness for dual fans for years '89 and earlier and '90 and later? I see several early year harnesses for sale but they specify those years only. It leaves me thinking the '90 and later is different. I have dual fans I would like to install on a '92 that has a single fan and would like to use the correct factory wiring. Also, is there a different area on the car the two different harnesses plug into the original wiring harness?