84 -86 engine side -firewall harness plug

[wahl4m]

i got a 83 chevy k-30 chassis -that i put a 85 &later chevy cab on it -is the engine side of the 83 firewall harness plug differant -than the 85 & later cabs ? i cant seem to get turn signals & have gremlins sometimes ? it just seems like the plugs are in differant spots ?? also seems like if i jiggle the inner side of plug-some of the stuff works-sometimes ? both sides of plug look alright !i thought id ask -before i dig into it further ? thanks for any info