[Pontiac1976]

Yes you need the 84 up wiring and 87 truck 88-89 Suburban Crew cab and the Colum with the option you're looking for. ** but your 81metal dash backer for the head light switch is not going to be in right place, no foot button high beam-84-87 face bezel, foot high button highbeam-81-83 face bezel, 88-91 face bezel large radio cut out, 83yr metal dash backer last year wiper on dash, 84yr is the best for cab Colum. But it deepens on the option want fuse box to dash all wiring in the cab the option the better than you will have merge your truck engine wiring with the newer cab dash wining do not cut anything it you want a/c do not have it all the wiring engine bay and cab. lots more work buy truck for the parts is the easist.