stereo rear speakers missing

[slfwilrr]

I have a 98 GMC Sierra K3500 crew cab dually that I can only find four speakers on the front doors. On the rear doors there is a place where there are grills/mesh that looks like speakers should be there but there are no holes cut out for speakers. When I pulled the door panels I did find what seems to be a speaker wire  connector but when I plugged a speaker into it there isn't any sound. Is there a place on the back of the stereo unit that I could check to see if they are hot? 

Where else on this truck would I find rear speakers? there looks like possible speakers on the rear door pillers but there is no sound coming from them. They look more like pressure relief vents?

I'm at a loss to figure out where they might be hid. it's hard to believe that there are no rear speakers on this truck. There is a 6 1/2 speaker and a small tweeter on the each front door but that's all that works.

When I use the fade button there is nothing when fade to the rear

Any help would be appreciated.

[Supreme Pizza]

GM will give you the build sheet for free, which lists what the OEM equipment was. 

 

You can splice rear speaker wires into the front speak wires to get them working, no significant drawbacks. 

 

 

 

 

[SarahsGMC]

The speakers are in the far rear pillars but they're a pain to get to, so most people get 6x9s put them in boxes under or on the seats.  You have to literally tear the whole back of the truck apart to get the speakers out.  I did a full stereo upgrade in my moms 97 Silverado and I did the 6x9 setup under the seat with all new wiring.

[slfwilrr]

I was actually able to fit 6 1/2 kickers in the rear doors. Under the grill, which pops out, I cut a hole in the each door panel and mounted them on the panel and then put the screens back. Kind of like it should have been done since they have the grill already there. And the Kicker are narrow enough that they don't touch the power window motors

Can anyone tell me which wires on the back of the stock radio control the back speakers?

[SarahsGMC]

https://www.the12volt.com/installbay/stereodetail/479.html

 

1998 Chevrolet C/K Pickup Stereo Wiring
Constant 12V+	Orange
Switched 12V+	Yellow
Ground	Black
Illumination	Gray
Dimmer	Brown
Antenna	Right Front
Front Speakers	6 1/2" Doors
Left Front (+)	Tan
Left Front (-)	Gray
Right Front (+)	Light Green
Right Front (-)	Dark Green
Rear Speakers	4" x 6" Side Pillar
Left Rear (+)	Brown
Left Rear (-)	Yellow
Right Rear (+)	Dark Blue
Right Rear (-)	Light Blue

[TBerk]

Sarah,

 

Great info. Is it possible that wiring chart will match a 93' C2500HD?  

 

It has four working (most of the time) speakers already, and while we've swapped some 'better' (but used) speakers into the dash, I'm going to be upgrading the whole mess, also due to the fact that the rears sometimes cut out.

 

(Not trying to hijack the thread, just wondering if those color match other years...)  Thx.