One thought I had, if this is a not used plug, isn't it dangerous to be left open? Should this be sealed some way, if nothing else, in case car got slightly flooded this is a pretty low spot (my car got caught in flash flood in 1980 ) - or is this a plug he would be likely to use in the future for something else?I know i'm late, but light blue/red stripe is standard in the Mustang for instrument illumination.
In this case, it is the PRNDL light plug. 2 wires in each side
As for the EVTM, I like this PDF version as it contains all 87-93 EVTM's and you can search it. $28 I do have paper copies as well but i rarely use them now. Above image taken from the '93 EVTM
