atspring

I realize this thread is rather old and cold, but this is the first info I've seen that might address my car. I have a 2008 C350 I purchased new. April 2008 German build with Navi. Acquiring Signal messages didn't start until 2016. Dealer couldn't find anything wrong. Problem is more common in the morning. Antenna is loose. In the next couple days I'll see if I can tighten the antenna and post results.

atspring

Last night I tried to get a Torx bit on the retaining screw by way of the rear dome light opening. That didn't work, nor could I really tell what size I needed.

Tonight it took about an hour and a half to take down the headliner (major PITA). The retaining screw was loose enough to tighten with my fingers. After removing the screw the antenna didn't want to come off and I didn't want to force it.

Two cables lead to the antenna. I assume one for GPS and one for Sirius. Neither cable looked compromised in any way and there was no sign water having got in.

I would expect the antenna to have it's own ground plane element so that grounding to the roof isn't required. Also, looking at how it's mounted I don't see that it would be getting a decent ground. The screw fits in a plastic block which pushes outward on four metal prongs on the antenna base thereby locking the antenna in the hole in the roof. Just the same, when I put the screw back in I tightened it down pretty well

The Torx socket on the screw head was somewhat rounded out and looks as if it was damaged during assembly, something that is not supposed to happen with Torx. I need to put a few more things back in place in order to drive the car tomorrow and see if there is still a problem.

While I was taking things apart I uncovered the Sirius module to see what type of antenna connector it takes (Fakra). At around $350 for a factory Sat Radio antenna, I may try an aftermarket antenna on the rear shelf.

atspring

Tightening the retaining screw may have done the trick.

Today I never got "Acquiring Signal". Also, there is an area in my commute where I've lost the Sirius signal almost every trip for several years. No problem today either direction.

While one day does not a trend make, I put most of the car back together this evening.

Anybody who wants to try reaching the retaining screw from the rear dome light opening, I believe I used a T20.

Good luck.

Augster

Can you tell me where the satellite module is located and how to access it (if it's not self-explanatory)?

I'm trying to verify that the previous owner of my girlfriends 2010 C300 with factory Nav/Sat physically took out the module because the SAT input option is not available when cycling through inputs and Sirius told her that the ESN (which was written in her owners manual) registered for her Vic is active with someone else.

And what resources did you refer to that guided you in removing headliner and accessing sat module?

TIA

Josh.A.Hussey

May be able to help you out Auguster with your vin.

ChrisBrown

One note - depending on where the module is in your vehicle, check for water leakage. On my C - it's tucked away in the right side of the trunk against the chassis under the liner. However, I figured out that water leakage from a cracked grommet ended up getting the module wet - that killed my first one. When I replaced it with the used module from a W211 E class, I wrapped it with a black garbage bag first before wiring it up so that it was sealed from any water from the rain or car washes.

These are sensitive modules (and expensive), so when you take a look (depending on the location) that no water may have leaked into it's location.

Augster

I already performed a VIN lookup and confirmed the original factory options included "Sirius Satellite Radio," along with Navigation and COMAND package.

Just can't find it in the input list.

I'll look in the trunk; in my 2008 BMW, the satellite module was also located in the trunk. But I think her's has been removed because my girlfriend has had the car now for at least 6 years (she only wondered about satellite radio when she saw it in operation in my new truck during our 2,000 mile road trip in it) and Sirius just told her that the ESN of the sat module belonging to her car is currently active.

Josh.A.Hussey

Shouldn't jump to conclusions.
I wasn't going to see if you had the package, I was going to get you an exploded view of where the module is. All good though, good luck!

Augster

Well, silly me! Why didn't you say that in first place for rocks like me!

I was also about to ask if there's online resources to get such information and parts lists, like there are for BMW's (e.g. RealOEM).

EDIT: Found one site: MBFans.me.

Got an exploded view and part number lists, including succeeding part numbers. Sat module, item #200, located in what appears to be right rear trunk area on a bolt-on shelf bracket, suggesting it's horizontal (e.g. on trunk floor, similar to my 2008 BMW 335i). I'll find out how it's really mounted soon enough now.