What's this plug?

[Kungpaodog]

It has 8 pins. The bottom left three are 12v switched power, the top right is ground, the red is the brakes lights, and i don't know what the rest do. It's below the passenger side tail lights, beneath the factory "woofer."

Can I use the switched power for other accessories?

Edit: I'm not sure how to embed photos from Google. Link:
https://goo.gl/photos/nHE1kFeG4Ct6W2CTA

 

[inkpot]

The correct trailer harness plugs on like a jumper between two of those plugs.

 

[bryson]

The correct trailer harness plugs on like a jumper between two of those plugs.

The trailer harness plugs in between the tail light plugs- the one pictured is not the tail light plug. Tail light plug is a 6-pin (3 over 3) plug, and if I'm not mistaken, only 5 pins are used. It's in that same bundle pictured, but it's higher up.

@Kungpaodog - did you unplug that one, or was it unplugged when you found it? I'd guess it is for rear AC or some other accessory that the US 80s didn't get. Maybe it's for the ambulance/barn door equipped 80s - the brake light signal could be for the 3rd brake light on the ambulance doors maybe?

Oh, and I see near the bottom of your pic that there is a Scotch-Lock on the harness - I'd guess that was where someone tapped in for trailer wiring at one time. That may be a place to start testing.

 

[Kungpaodog]

I found old 4 pin wiring on the driver's side, and the 3 over 3 plug for the taillights, but this one is a mystery. Yes, it was unplugged when I found it, and I don't have any systems that are on the fritz, so I think it's been unplugged like this since it was built.

 

[bryson]

I wouldn't worry about it. There are plenty of unplugged/unused pieces in our 80s.