I have a 89 civic hb using the 89 hatch's dash harnessess, (2 connectors) I have a 90-91 usdm si cluster that i want to use. It has the 2 connectors (8 pin and 12 pin) plus a third smaller one on the back. I have the 91 crx service manual, and looking through it all I could come up with for the 3rd smaller plug is its for the hf? Has anyone done this rewiring conversion? I have done some reasearch and all fingers point to not plug and play. I would be willing to swap the 90-91 si cluster and hood for an 88-89 si cluster and hood in good shape or a good idea on how to make this one work. Thanks in advance!

Dose3782