Also posted on the Mav forum and it seems that the most common theory is 4 positive speaker feeds off the radio then a common ground like sunfire posted.

 

Thanks. Yep 11 months at work in our body shop. Weekends and after work. Original paint Texas car but was full of dents. No rust anywhere. Has a nice sleeper stock look but its not.
Plan on installing one of those Secretaudio systems in the trunk eventually. Dont like new systems visible in an old car.
Looks like the radio is a common ground system.

 

Well got the old Pioneer Super Tuner in the MAverick today and it works great. All 4 speaker neg go to the common ground.

 

Looks about right.....

Keep it coming.....

 

Where are the airbags? What's that chrome thing hanging on the front? J/K

Very nice clean ride.

 

Very cool ride, love those dog-dish wheels too.....

 

Hey, the chrome ones were extra when the car was new......

Next time you guys have a meet Mavman let me know, I'd love to check it out...

 

Looks like I got into this thread a little late but yeah the old Pioneer decks had 4 speaker positive and a single speaker negative with 4 bullet connections on it.