Steering Wheel Controls Not Working

CMcraz23 · Jul 21, 2009, 06:05 PM

Sometimes my volume controls and my Up and Down arrows dont work right. The volume plus lowers the volume....its like the control i hit does the reverse.

any ideas?

i go this thursday (7-23) for my oil change and state inspection. how would i tell them this or what to look at?

thanks!

jer301 · Jul 21, 2009, 06:22 PM

Hmmm. I am an Electrical Engineer by trade and this sounds like a ground problem. if the radios ground pin in the harness or Ground conductor is loose, and the volume buttons use a linear feedback input, without the reference ground this type of thing can happen. This happens in PLC type interfaces all the time. Iwould explain this to the dealer exactly as you stated in the thread. I'm sure they will check the radio wiring harness connections and possibly the slip rings in the steering wheel. Of course i am probably biased b/c 95% of the problems I find with systems at work can be fixed with proper grounding methodology.

CMcraz23 · Jul 21, 2009, 06:28 PM

yeah its odd...it just started to happen and it only happens selectively....

thanks i will let them know

kalpakiotis · Jul 22, 2009, 05:23 AM

I agree with jer301. Its always a stupid ground, or loose connector...

CMcraz23 · Jul 29, 2009, 01:55 AM

They looked at it and didnt notice anything.....oddly it hasnt done any acting up lately...

jer301 · Jul 29, 2009, 04:41 AM

maybe if they took everything apart and put it back together it fixed the problem. loose connections and ground faults can me very hard to find. while they are loose they fault is intermittent in nature so it is difficult to show the dealer until the equipment fails completely. The only way I have ever been able to find them is by testing the wire by ohmeter checks.

CMcraz23 · Aug 1, 2009, 05:38 PM

well hopefully it doesnt happen again.

thanks for your help

jer301 · Aug 7, 2009, 05:25 AM

Quote:

Originally Posted by CMcraz23

well hopefully it doesnt happen again.

thanks for your help

Well looks as though I may eat my own words a little on this one. steering wheels that have controls built in do not use slip rings to send the signals where they need to go and they don't use linear (analog) controls either. in fact one of the other Engineers I work with worked for ford and all car companies use something called a clock spring to mount controls in the wheel. the clock spring allows the wheel to rotate and the controls to maintain electrical connection. The buttons themselves send digital signals which are Multiplexed together by a Multiplexer.

Here is a link for the description of a multiplexer:

http://en.wikipedia.org/wiki/Multiplexer

A MUX must have three things to work correctly, Voltage (VCC), Ground reference (GND), and a clock signal. My co-worker told me that these can fail from time to time but more than likely a connection was loose and you were loosing either the clock signal or ground. Basically, this points to loose connection. Hope this helps.