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Author Topic: Steering Wheel Controls Problem  (Read 253 times)

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Trey

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Steering Wheel Controls Problem
« on: 05/23/18 03:00 PM »

Does anyone understand exactly how the steering wheel controls work?  I was having some problems with the stock head unit, where steering wheel buttons would occasionally do the wrong thing.  Like "seek up" would switch the radio band, for instance.  Now with a new head unit and PAC module I get intermittent errors of buttons doing the wrong thing.  It is configured correctly.

There are more buttons than there are wires, so it has to be more complex than simple open or closed 12v circuits. I'm wondering if the system works based on different output voltages coming down the harness from the steering wheel to the head unit (or module).  Maybe each button applies a different resistor value, so it results in a different voltage that corresponds to a specific command.  If the copper button pad gets old or the semi-metallic rubber feet buttons get worn, perhaps it could result in higher resistance when pressed, and maybe a different command is interpreted.  I cleaned the contacts, but the problem continues.  Anyone knows exactly how this works?
« Last Edit: 05/23/18 03:25 PM by Trey »
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2004 Silver Birch AV 4x4, Leather, CD-Changer, DVD, chrome steps
MODS: TRUXXX Leveling Kit, HIDs, Full-Time Amber DRLs, All-8-on-Hi-Beams Mod, A/C Vent LEDs, Metalcast Engine cover, Headlight and Backup Light Strobes, Sail Panel LEDs, 81-LED Lighted Bowtie, Color-changing LED Headlight Accents, Black Flames, 20" Dub X-Wang Wheels, Power Locking Tailgate, Train Horns, Line of Fire, Smoked Taillights.

MS03 2500

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Re: Steering Wheel Controls Problem
« Reply #1 on: 05/23/18 06:33 PM »

You are correct each button sends its own signal thru clockspring over to the radio via the Class 2 bus.

I would get a new button for the one you have a problem with, then see if it's the button or something else.

They sell Dorman replacements for 20 bucks a piece or 70 for a set.

Make sure the pins in the main harness are in good cause the data circuits are real touchy.
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redheadedrod

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Re: Steering Wheel Controls Problem
« Reply #2 on: 05/27/18 09:51 PM »

The Radio controls are Resistance based. They are NOT serial Data...

Attached are pictures taken from service manual on O4.

First two are pinouts of the buttons.

Next two are from service manual diagnostic section. Explains what you should see

Last two are for the BCM.
First of the BCM shows "Steering Wheel Radio Controls Supply Voltage"
Second shows "Remote Radio Control Signal".

The BCM reads the resistance from these buttons and converts to VPW datastream which goes to the radio.

Rodney (Was bored so stopping by. May not be back again for months so good luck!)



 
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2003 Cladded Black Z71 - PC installed otherwise mostly stock.
4 Light Brake/Turnsignal
All on high and FTDRL (BCM friendly version)

MS03 2500

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Re: Steering Wheel Controls Problem
« Reply #3 on: 05/27/18 11:04 PM »

How come the pinout show 5 pins when it only has 4.

Welcome back Rodney.  :D




PS one of them is not here used, only 3 wires are there.
« Last Edit: 05/28/18 12:05 AM by MS03 2500 »
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redheadedrod

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Re: Steering Wheel Controls Problem
« Reply #4 on: 05/28/18 07:00 AM »

How come the pinout show 5 pins when it only has 4.

Welcome back Rodney.  :D




PS one of them is not here used, only 3 wires are there.

I cut and pasted from the service manual.. Heck, '03 didn't even have the steering wheel in it. Although it said go to the "entertainment" page it wasn't there... In '04 this is what was there. Maybe '05 has it all right...

So glad I didn't spend $700 for this... lol
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2003 Cladded Black Z71 - PC installed otherwise mostly stock.
4 Light Brake/Turnsignal
All on high and FTDRL (BCM friendly version)

old skool

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Re: Steering Wheel Controls Problem
« Reply #5 on: 05/28/18 08:44 AM »

I was having the same problem. Did you use splice connectors on your wiring? I went back in and soldered all my connections and that seemed to help. I still have some intermittent times where the buttons don't respond at all for some reason.
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Trey

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Re: Steering Wheel Controls Problem
« Reply #6 on: 10/07/18 10:59 AM »

Thanks for the excellent info, everyone.  Yes, I soldered all my connections between the factory harness and radio harness and steering wheel module.  I still get some errors.  I think the original button pads are just old and have some built-up resistance to them, depending on how firmly and completely they are pressed.

 
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2004 Silver Birch AV 4x4, Leather, CD-Changer, DVD, chrome steps
MODS: TRUXXX Leveling Kit, HIDs, Full-Time Amber DRLs, All-8-on-Hi-Beams Mod, A/C Vent LEDs, Metalcast Engine cover, Headlight and Backup Light Strobes, Sail Panel LEDs, 81-LED Lighted Bowtie, Color-changing LED Headlight Accents, Black Flames, 20" Dub X-Wang Wheels, Power Locking Tailgate, Train Horns, Line of Fire, Smoked Taillights.
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