Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 6th, 2021. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Kenwood head unit doesn't dim with headlight switch

Recommended Posts

The double DIN Kenwood unit in my C2 coupe doesn't dim with the headlight switch or the dashboard dimmer knob. The factory gauges do dim down as expected. I can manually dim the Kenwood via the touch screen menus but then it is too faint for daytime driving. The deck (DNX6990HD) is pleasing in all other regards. I just spoke to Kenwood and Crutchfield, they were apologetic but could not provide technical advice.


My real concern is that the digital dimming function in the 997 is in some way incompatible with the orange/white wire on the Kenwood that expects (I suppose) a variable dc voltage like it would get form a "normal" car's dash dimmer potentiometer.


A visit to my local car stereo shop produced a four figure quote for pulling everything out and starting over from scratch. Anyone happen to have experience with this? 


Link to comment
Share on other sites

As the illumination is by LED's then the dimming is not variable DC but by pulse width modulation. This is varying the amount of time the LED's are illuminated by flashing them too fast for our eyes to see the "flashes" this reduces the average time they are on hence the effect of dimming them. I assume the headunit you refer to is non OE? If so then it will not work unless it has been designed to work with 'dimmed' LED circuits.

Link to comment
Share on other sites

Given the popularity of adding/replacing the factory "stereo" with units that have HD, blue tooth and GPS built in, I suspect that this is an issue that has been encountered (if not discussed) before. 


If I can figure out how to pull the head out of of my dash I will "scope" the dimming signal if it is available in the stock radio connector. I'll start looking for a radio connector break out diagram for 2005 997.1 with Bose.


If the dimming signal is PWM--as jl-c predicts--then I will build a little ac-coupled DAC to provide the dc levels that the radio (presumably) expects. Based on yesterday's phone call to Kenwood I don't think they will provide the details on what the signalling of the orange-white wire is supposed to be. Surely there is a Kenwood car stereo forum where I can get that information.

Link to comment
Share on other sites

Looks like the Kenwood radio doesn't support variable dimming from the dashboard control. It simply switches from "bright" to "dim" when it detects the headlights are on. This should make debug easier but the end result will not be quite what I expected.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.