Next is the 14pin Externally amplified Stereo
Here is a picture of the back of a 14pin stereo
And here is a picture of the 14pin connector that plugs into the 14 pin radio
Here is the pinout of the 14pin connector
1:AMP
2:ILL+
3:+B
4:MUTE
5:FL
6:FR
7:ANT
8:LL-
9:ACC
10:GND (SLD)
11:SGND (FADE)
12:BEEP
13:RL
14:RR
Next is the 15pin Externally amplified Stereo
Here is a picture of the 15pin connector on the back of a 15pin Stereo
And here is a picture of the connector that plugs into the 15pin stereo
Here is the pinout of the 15 pin
1: AMP
2: ILL+
3: ACC
4: +B
5: MUTE
6: FL
7: FR
8: ANT
9: LL-
10: (normally unused)
11: GND (SLD)
12: FADE
13: BEEP
14: RL
15: RR
You can easily add a aftermarket head unit and continue to use the Factory amplifier.
You will need to buy a “Toyota amplifier integration harness”
I think it is made by Metra and the part number is 70-8112
It looks like this
Next is the 20pin Externally amplified Stereo
Here is a picture of the 20pin connector on the back of a 20pin stereo
Here is a picture of the 20pin connector that plugs into the stereo
Here is the pinout of a 20pin
1: +B
2: ILL+
3: AMP
4-6 (typically unused)
7: MUTE
8: FR
9: FL
10: GND (SLD)
11: ACC
12: LL-
13: ANT+
14, 15: (typically unused)
16: FADE
17: BEEP
18: RR
19: RL
20: GND (ground to chasis)
The 20pin externally amplified system can also use a Amplifier integration Harness
I believe it is made by “Metra” and the part number is 70-8113