stock sub-amp: what does the "enable" input wire do?

[saxon]

Looking at the wiring diagram for a stock subwoofer amp from a 1995 Audiophile system. Diagram shows two power wires (pos. & neg.), to output wires(pos. & neg.), two input wires(pos. & neg.), and an "enable" input wire (connection #2 on left side of amp image).

Image of 1995 Audiophile subwoofer amp wiring diagram: http://www.explorerforum.com/forums/showpost.php?p=1070491&postcount=2

What's the 'enable' wire do? Or more importantly, what signal is it supposed to provide to the sub-amp? Is it supposed to be a 12v source from the HU?

I'm trying to hook up the stock subwoofer amp & subwoofer speaker to a Kenwood HU in a 1991 Audiophile system. The stock amp is by-passed, the door speakers all sound great, and the subwoofer speaker is good but I can't get the subwoofer to work via the stock amp. I'm not running anything to the "enable" input, though and perhaps the amp is looking for some signal before it turns on?

 

[jwrezz]

I believe it's a "trigger" 12v source. When the HU turns on it sends a trigger to the amp to turn it on. I can't be sure on the voltage tho. I'd assume 12v. Most heads have a 12v output to turn on an amp. It is NOT a 12v source to supply the amp w/ power tho. Good luck