Well I assume by "booster" you mean new head unit that will replace the big factory one. The back of your stock radio will have a 16 pin harness that contains power, ground and speakers wires and possibly a 20 pin connector that controls the rear seat radio controls. To install your new head unit you will need to disconnect all connectors on the stock radio and buy a 16 pin wiring connector from walmart (Scosche FD16, Metra 70-1771) that wires up to your new HU and then snaps to the factory one. Now you have new tunes to all 4 speakers with improved power from the new HU. The 20 pin connector remains disconnected and the rear seat controls are unusable (heat/air controls work fine though).
To add a sub you can do a couple things. You can splice into the rear speaker wires (see below), either behind the dash or under the door sills, and connect to an amp with high level/speaker level inputs. Then wire the sub box to the amp. Plus of course new power wire to the battery and new ground.
If you new HU has subwoofer RCA outputs then no splicing, just rca cables to the new amp
1998 Explorer XLT Premium System w/ amp integrated into radio chassis
my truck came with rear seat controls but NO subwoofer,NO power
antenna, NO CD changer.
Stock AM/FM CD Cassette "Dual Media" part# F87F-18C868-CC
Typical harness to add aftermarket stereo - Scosche FD16, Metra 70-1771
Typical harness that connects into radio and would be needed if
stock harness was damaged - Scosche FD16R, Metra 71-1771
pin#-stock---------------aftermarket---function
1----DrkGreen/Orange---grey/black---RtFrnt-
2----White/Green-------grey---------RtFrnt+
3----Brown/Pink--------purple/black-RtRear-
4----Orange/red--------purple-------RtRear+
5----empty-------------empty--------(amp turn on for audiophile unit?)
6----Pink/Black(thin)--empty--------(pwr antenna?)
7----Black-------------orange/black-grounding dimmer
8----Pink/Black(thick)-orange-------illum/dimmer
9----Black/Green-------black/white--amp ground
10---Blue/White--------white/black--LftFrnt-
11---Orange/Green------white--------LftFrnt+
12---Tan/Yellow--------green/black--LftRear-
13---Grey/Blue---------green--------LftRear+
14---Black/Green-------black--------Chassis Ground
15---Yellow/Black------red----------switched Acc 12V
16---Green/Purple------yellow-------batt constant 12v
*Looking at stock Black connector w/red
leading edges.
____ _______ ____
| | | | | |
-------------------------
|1 |2 |3 |4 |5 |6 |7 |8 |
------------------------
|9 |10|11|12|13|14|15|16|
-------------------------
*I checked all wires but could not find a
12V source that was switched when the
radio was turned on for my "remote"
external amp turn on. I ended up
using the yellow/back switched Acc.
