My car will be a drag car only, so I want to bypass the rear hatch key with a button. I have it ran in Parallel with the hatch release button from the inside of the car so both of them work. I tested them out and they both function correctly. However, they only work with the ignition on. I want the one on the outside of the car to be hot all the time. Any help would be appreciated

 

That is really weird that your's only works with the key on , the hatch release button on mine only works with the key off . I always figured it working only when the key was off was a safety feature , having it only openable with the key off would prevent it from being opened while driving . I do know that the wiring on my car is factory unmolested , so I think mine is correct for 1989 , has your car had any kinds of wiring alterations in the dashboard area ?

I couldn't find a 1991 specific wiring diagram , but I found this one for 1992 . If they are both wired the same it appears normal function for yours should be that as long as the shifter is in park or neutral (for automatic) or the parking brake engaged (for manual shift) the button should be active irrespective of key position . Since you say yours only works with the key on I'm left to wonder (If yours is the same as 1992) if someone for some reason moved the orange constant power wire feeding the hatch release relay's coil (top left of the drawing) from it's constant source of 12V to a switched source instead , for whatever unknown reason .

 

Would VATS play any factor in this? When I bought the car and there wasn't a VATS chip in the key, nor was there a fuse in the VATS spot in the fuse block.

 

Here's a schematic that's a bit easier to follow: from the 85 shop manual,....... If you 'tap' into your factory wiring on the ORANGE and the BROWN wires then the exterior button should work just like the factory mounted button.