Rear turn signals & Audio not working

Subscribe
Jun 9, 2019 | 05:29 PM
  #1  
Hi, I just acquired a 2008 CLK550 and have been using this forum to trouble shoot several issues for about a week now and have learned a lot. However, I still have two major problems I need help with. Forgive me if my terminology is not spot on, but I'm a recently single female, trying to fix my car on my own and this whole car repair thing is new to me.

Problem #1 - Rear turn signals not working. I have checked and/or replaced all of the fuses in the car. I replaced the bulbs. The brake, back-up and reverse lights work fine. The left turn dashboard indicator flashes and clicks rapidly and the right one blinks at a normal rate but neither light works. I have checked for any disconnected or loose wires in the immediate area of the light assembly and found nothing.

Problem #2 - No sound from the audio system. Everything appears to be working per the display, Navigation and CD's can be loaded and ejected, can operate scan and seek for radio, but no sound. There is a CD changer in the glove box that doesn't seem to work. Nothing happens when you press to eject magazine and it isn't recognized in the display window (unless it's noted as Aux in the upper right corner of the display) Again, I have checked and/or replaced all fuses but that's as far as I got. I read here that all components are on a continuous loop and if one of them is not working/connected it affects the others. Should I start further trouble shooting by pulling and checking the CD Changer? I am so fed up and frustrated at this point, UGH, but taking to a dealer isn't really an option right now. Any help or suggestions would be appreciated.
Reply 0
Jun 9, 2019 | 10:10 PM
  #2  
Welcome tot he forum!

The turn signals are not powered through a fuse. They are controlled and electronically fused by he rear SAM (Signal Acquisition Module, a small computer in the trunk which is part of the fuse panel there). Since you have replaced the bulbs, my guess is that it's a wiring problem. Check the bulb sockets for corrosion. Check the wiring harness on the tail light assembly for any obvious issues. Try swapping bulbs from side to side.

The radio problems sounds like the MOST fiber optic loop is "broken". The CDC could be the culprit. You said you replaced the fuses, but check #20 (in the trunk) to make sure it's good - it controls the CDC. If you suspect the CDC is bad, you can remove it and bypass the it on the fiber loop. Removal is easy - there is a single screw in the "roof" of the glove compartment housing holding its front right corner in place. Remove that and you can pivot out the whole CDC. You can by a MOST fiber coupler/bypass adapter to complete the fiber loop once it's removed.
Reply 0
Jun 9, 2019 | 10:17 PM
  #3  
Rodney, Thanks so much for your response. I'll give those suggestions a try and cross my fingers.
Reply 0
Jun 10, 2019 | 05:22 PM
  #4  
When I replaced the #20 fuse for the CDC it sparked and stayed lit up, so I guess something made it blow, correct? I got another fuse which also sparked but its not the kind that lights up when blown. CDC still doesn't work. Why is it sparking and how do I determine if the second fuse is blown too? Dumb question, but does that mean there's an electrical short in the wiring?
Reply 0
Jun 11, 2019 | 09:24 PM
  #5  
Yes, there is a short in the wiring, or maybe a failure inside the CDC itself. I'd remove it and see if you can find any obvious issues with the electrical wiring plugged into the back of it.
Reply 0
Jul 12, 2019 | 06:49 PM
  #6  
"recently single female"

Just gotta say that's a great phrase to throw into a post.
Reply 0
Jul 12, 2019 | 10:49 PM
  #7  
Quote: "recently single female"

Just gotta say that's a great phrase to throw into a post.
You know, it matters not to me what gender, color or marital status a forum member is. I'm just excited to see so many people trying to tackle things for themselves instead of paying exorbitant rates to shops with mechanics who half the time do more harm than good,
Reply 0
Jul 15, 2019 | 04:10 PM
  #8  
Quote: "recently single female"

Just gotta say that's a great phrase to throw into a post.
Wow, I thought this forum was a place to get helpful info for DIY auto repairs, not a review site for posting unsolicited critiques...
Reply 0

MB World Stories

The Best of Mercedes & AMG

Explore
story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

 Verdad Gallardo
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

 Verdad Gallardo
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

 Verdad Gallardo
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

 Verdad Gallardo
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

 Verdad Gallardo
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

 Verdad Gallardo
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

 Verdad Gallardo
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

 Verdad Gallardo
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

 Verdad Gallardo
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

 Verdad Gallardo
Jul 15, 2019 | 04:14 PM
  #9  
Update: The SAM was burnt out and had to have it replaced, but I have turn signals and audio now, Yahoo.
Reply 1
Jul 15, 2019 | 06:06 PM
  #10  
Quote: Wow, I thought this forum was a place to get helpful info for DIY auto repairs, not a review site for posting unsolicited critiques...
My apologies. A part of me thought that was amusing. I see now that it isn't.
Reply 0
Jul 17, 2019 | 09:21 PM
  #11  
I appreciate your apology. In that post, I was merely trying to convey my desperation by establishing the fact that I am attempting to tackle these repairs on my own and am completely void of any knowledge re: auto repairs. I hoped that any responses would, therefore, be relayed in basic easy to understand terms.
Reply 0
Subscribe
Currently Active Users (1)
 
story-0

6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1

Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2

Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3

8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4

Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5

Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6

Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7

5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8

Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9

10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE