According to http://www.installdr.com/Harnesses/GM-Wiring.pdf the connector for the rear speakers is separate from the front speakers. If the connector for the rear speakers is loose or disconnected, the rear speakers would not work while the front ones will. The amp in the head unit (dashboard radio) powers the front door speakers. The rear door speakers and roof (pillar) speakers in the rear are powered by a second amp under the drivers seat. Either this amp is bad or is not hooked up.
6.5 componets up front and 4x10's in rear
It varies depending on model year but most Ford Crown Victoria's have 5x7 / 6x8 speakers in the doors and 6x9 speakers in the rear deck. Station wagon models have 5x7 / 6x8 speakers in the rear cargo area. The links below have a lot of useful info on the subject for 1992 and up Crown Victoria models... Front speakers: http://www.autoclinix.com/Mercury/Front%20Speakers.html Rear speakers: http://www.autoclinix.com/Mercury/Rear%20Speakers.html Depends on the year of the car, and which speakers.
rear cab speakers are usually 5x8s or 3x6 front dash speakers are 5" i think its been awhile.
6.5" up front in the doors and 5.25" in the rear doors. if yours has the speakers in the rear pillars by the hatch, those are 3".
you match them with the same colors
ok so your rear deck is going to have to come off. 1. you have to put down both seats 2. you should see about 6 little plastic screw like pieces you pop out the inner part of them and then pull out the rest of the piece then go in your truck and look up and you should see 3 Orange clips and squeeze them with pliers then go ahead and pull up on your rear deck and pull toward the front of the car and it should come out but be careful as the rear brake light will have a plug in it and you need to make sure you unplug it or you could damage your wiring harness then you should see your speakers with 4 screws unscrew them and then they come out you have to disconnect your speakers wires and then put in your new speakers and cut the speakers wire and solder on your new speakers.
While researching some upgrades for my '92 gmc pick up, I was referenced to a fitting guide that listed 4"x6" speakers. I think the rear speakers are the same size, as I havnt found any listing for other size speakers. Hope that helps.
The speakers in a 1985 Toronado are a pair of 4x6" in the dash up front, and a pair of 4x10" in the rear, under the package shelf (access through the trunk).
I don't know but really, it won't matter in the least as long as you mate up the rear and front speakers in the same color code. If you decide the Red is neg in the rear, then it has to be negative in the front too.
Usually 6.5" in the front doors and 6x9 in therear deck. Best to check the stock ones before purchasing speakers. They could end up being 5.25" in the front and 5x7 in the rear deck.
Crutchfield.com states that you can use up to 6"x8" in front doors and the same for rear deck.