73 and 74 Wiring harness Help!!!

[purple70rt]

Hey Guys,  I bought a big lot of 73 and 74 RR stuff.  It has a nice underdash harness, but I am not sure if it's out of a 73 or 74.  I want to use it in my 73 GTX, but do not want to if it's off of the 74 due to the seatbelt interlock system.  I have never dealt with this, but from what I hear it is a pain in the rear.  Is there any way I can tell what year it's for?  Any special plugs for the seat belt stuff?

Thanks In advance!!!!

Dale

[Nacho-RT74]

74 does have the interlock seatbelt system with around 4 extra plugs than earlies doesn't have, but the best way to difference is that 2 of those extra plugs are conected on a big plastic box. The control box is the easier way to difference.

Circle number one is the interlock control box. this one is bule, but mostly are orange... I have seen them also yellow. Uses 2 white plugs
Circle number two is the plug to multibuzzer function ( seatbelt, key in and lights on warning buzzer ).

There is anoter plug around, similar to the "wafle" kind to rear harnes on driver side kick panel, but this one is to passenger side kick panel. This plugs on to a harness located undercarpet to seatbelt and seats sensors.

[Nacho-RT74]

If is a 74 harness I would love that you take a pic of all the harness extended. I removed that system because I didn't have the complete parts of that so I Untaped and remove all that stuff from the harness. Now that I'm getting all the system ( specially buzzer and rest button down the hood ) I'll install again and I want to re-tape everything just like original was, but don't remember where was all the harness "arms" splicing from tape hehehehe.