steering wheel harness

2005 TOYOTA SIENNA
110,000 MILES • 3.3L • V6 • 4WD • AUTOMATIC
Avatar
PCULQUI
  • MEMBER
  • 354 POSTS
I am sending 2 pictures of the harnesses in the factory radio. I installed an aftermarket radio and it works well. The steering wheel controls are not working due to the fact that one of these 2 harnesses need to be connected to the KEY1, KEY2 and ground of the aftermarket radio.
The vehicle has an audio player in the back which means one of these harnesses belong to it and the other to the steering wheel controls.
So the question is, which of the below harnesses is the steering wheel controls and which colored wires belong to the steering wheel controls?
Images (Click to enlarge)
Attached Media
Attached Media
Attached Media
Attached Media
Nov 10, 2020 at 9:21 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
Hi,

I thought this would be an easy one to answer until I tried looking up the wiring schematics for the systems. I need to know which system was in the vehicle originally.

As far as your pics, the black connector's wires look rather heavy for what would be needed. However, we'll try to figure it out for sure.

Take a look at the attached pic and let me know which stereo this vehicle came with from the factory.

I will watch for your reply.

Joe
Image (Click to enlarge)
Attached Media
Nov 10, 2020 at 12:53 PM
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,113 POSTS
Looking at the wire colors you are looking for a yellow wire as the ground, a light green as switch one and a blue as the switch two. Looking at the wiring it appears you can verify the ground and switch 2 wires by connecting a VOM across them set for continuity and then pushing the mode button. That should make a zero ohm circuit. Also, to test the switch two wire you can connect to the light green and yellow and push the seek plus button and complete the circuit.
Image (Click to enlarge)
Attached Media
Nov 11, 2020 at 3:24 AM
Advertisement
Avatar
PCULQUI
  • MEMBER
  • 354 POSTS
Can you repeat the part "Looking at the wiring it appears you can verify....." in a more non-tech vocabulary so I can follow you.
Nov 11, 2020 at 5:47 AM
Avatar
PCULQUI
  • MEMBER
  • 354 POSTS
6-speaker system circuit (with out Navigation with rear seat audio).
Nov 11, 2020 at 5:54 AM
Avatar
PCULQUI
  • MEMBER
  • 354 POSTS
Can I crimp the yellow wire with the black wire in the same 20 pin harness in the pic I sent to provide power?
Nov 11, 2020 at 5:55 AM
Avatar
STEVE W.
  • CERTIFIED EXPERT
  • 15,113 POSTS
The diagram shows the three control wires. The way the switch works however is to provide a certain resistance between the three wires when none of the switches are pushed. That would make it difficult to test them as the resistance isn't shown. However by pressing the switches you can remove that resistance and create a solid circuit. So if you connected a meter between the Yellow wire and the light green wire like the red line and push the seek plus button it would show a short. Then if you connected the meter to the yellow wire and blue wires like the black line and pushed the mode button it would show it as a short. The issue I see with your radio could be in how it works with those controls. If the unit uses just an on off switch then the factory steering wheel controls will probably not work because the various resistance levels used with the OEM stereo may confuse the aftermarket one.
The yellow wire in that harness you show isn't power, it is the signal ground that only connects between the factory radio and the control switch.
Image (Click to enlarge)
Attached Media
Nov 11, 2020 at 10:25 AM