Sports Coupe - Poor phone/radio reception

[The Dent Guy]

Are Sport Coupes known for breaks in the wiring at the hinge of the tailgate?

My car has telephone pre-wire option with the stubby ariel on the top of the tailgate.

Problem is, for the last 2 or 3 months my bluetooth SAP phone device has dropped calls and not received calls whilst the signal strength was 3 bars or less. If the signal is between 3 and 4 or 5, then the device works fine.

Before this problem, the device worked fine on 1 or 2 bars of signal.

Similarly, i have noticed the radio reception isn't that good these days and have noticed that when i pull up onto my drive at the end of the day while the radio is tuned into a strong station, when i start off in the morning having not touched the radio, the reception is very poor, bordering on non existent until i change the station. Also thr general reception for the radio whilst driving around is generally quite poor now.

Initially i thought the problem was the bluetooth cradle, but now im thinking there may be a break or weakness in the wiring at the hinge of the tailgate. I noticed there is a black rubber conduit at either side of the top of the tailgate.

Is there a test for audio antenna and phone ariel connection?


EDIT...... think it might be worth noting that i open and close my tailgate a fair bit on a daily basis!

 

[television]

203 aerial amps are always going down,, the other thing is that the inner wires can break where they plug in

 

[The Dent Guy]

203 aerial amps are always going down,, the other thing is that the inner wires can break where they plug in

Yeah i read this in the forum too.

But, Is there a way to do a continuity test for both radio and phone antennas?

 

[The Dent Guy]

203 aerial amps are always going down,, the other thing is that the inner wires can break where they plug in

Did you mean where the wires plug into the ariel or back of the audio system in the dash?

 

[The Dent Guy]

Update.....help!!

The radio appears to be reasonably ok - BUT - its the poblem with the phone reception thats bugging me. Between 1 and 3 bars wont make or receive calls and drops current calls with a common sequence ie. when the signal strength drops to 3 bars the other person loses my voice but i can hear them fine, until the call is finally dropped - probably by the caller.

Done a few tests....

1. Put the heated rear demister on whilst radio on - then whilst attempting to making a call in low and high signal area = no difference at all.

2. Opened tailgate and repeated test 1 above = no difference at all.

3. Bought new SAP V2 device from MB main agent = no difference at all

4. Checked wiring at the tailgate hinges - did continuity test for off side (2 cables)= ok, for near side (loads of cables in thick harness going to rear SAM) = managed to test 2 ok, couldn't test others but i see no reason for break in the wires)


So - i am considering booking the car in to the MB dealer for a Component "short" test for £35 (0.3 hrs) to see what they might find.

The other thing is, whilst searching the forum i found something called "the antenna cable loss compensator". Whats this? and could this be the problem? How does the pre-wire phone system connect to the audio 20? Could it be that?

All help appreciated - i understand that the most likely people with the knowledge is Richard, Miro and Alfie.

Cheers guys

 

[richard]

The compensator is/was a little booster for the GSM1800 mhz (orange. t-mobile) networks - but they have since (in 2006) stopped bothering to fit it. It is sort of known as the 'e-net compensator'

The rear-window defroster thing affected FM / AM receoption when the antennas were broken because those antennas are in the rear window.

The GSM antenna is seperate, but I don't know where it is on the Sport Coupe.

The anntenna lead goes from under the UHI connector (where there is a plug/socket pair), to the compensator (if you have it), and to the antenna - so not a lot of places for trouble,
The compensator has a male and female socket, so some cars will have a compensator, some won't and the leads will just be connected together, and later cars wont even have a male/female connector set for the compensator (i.e once they dropped it from the wiring loom).

If the cable is broken near the UHI connector (or it is unplugged), you usually end up with no signal - especially so with SAP. - so i'd be looking at the antenna and e-net compensator end. If you can find the compensator, then you could just unplug the coax'es and connect them together.

What operator are you using ?

Richard

 

[GTEvo]

The GSM antenna is seperate, but I don't know where it is on the Sport Coupe.

The GSM antenna is stuck to the tailgate glass right at the top. It is an inductive device so the wire from the UHI will terminate at a pad stuck to the inside of the tailgate glass, directly under the external antenna.

I recently had my tailgate glass replaced (alarm fault) and the guys fitting it had a hell of a job picking up the exact position to stick the new external antenna. Also, the tailgate trim was very difficult to refit

If the external antenna looks fine, maybe the internal pad has started to detact.

 

[crockers]

when you say 2 - 3 bars of reception where is that showing? On your phone or on the display. If its the later - then the aerial is getting the signal...

A weird one - hope its a simple fix....

 

[The Dent Guy]

Would a "short" test at MB find the fault?

What operator are you using ?

Richard

Am using Orange - just renewed 18 mth contract too

The GSM antenna is stuck to the tailgate glass right at the top. It is an inductive device so the wire from the UHI will terminate at a pad stuck to the inside of the tailgate glass, directly under the external antenna..........

If the external antenna looks fine, maybe the internal pad has started to detact.

When i removed all the trim yesterday, i could only barely see the underside of the ariel - looked like a circuit board. But its encased by the tailgate.

2 options here - either drill a big hole or replace the glass....i don't fancy doing either

when you say 2 - 3 bars of reception where is that showing? On your phone or on the display. If its the later - then the aerial is getting the signal...

The signal strength is on the audio 20 display.

Today, i was beginning to lose people at 4 bars - but also noticed that the signal was varying wildly....from 5 bars to 2 in a matter of meters (literally), although i was driving between Gloucester and Chepstow which is up hill and down dale a heck of a lot.

Would a "short" check at MB dealer show up a fault with either the pad coming away or the 'e-net compensator'? Not a lot of money i know, but would i be just throwing away £35?

Or could it be the audio 20?

 

[Diesel Benz]

Couldn't you test the phone set-up with an external GSM antenna. I assume you have a short coax cable from the UHI connector (hidden somewhere, depending where your UHI connector is), find an adapter that fits directly to this connector. The phone should work quite well even if you lose the antenna compensator.

The compensator actually might be one that may have failed, or the connectors, you could try to by-pass that too.

The radio is there for voice only (OK, the user interface), it cannot cause dropped calls.

 

[The Dent Guy]

UPDATE 2

Just returned from MB Chelt and Glos.

The guys in the workshop seem to think that the compensator was only on early examples and for this rerason they have assumed that my car does not have one. Is it possible to check for sure from the chassis number? They said if it did exist then it would be located in the C pillar or quarter panel (they didn't say which one).

Also, i was informed that the "short" test would not be of any use. They said it can only tell if there is a breakdown in the communication between the control modules around the car - which in turn won't tell me where the fault is located.

They have intimated that it "might" be the control module on the underside of the GSM antenna. This is £240 +VAT and can't be replaced without replacing the rear screen at £160 +VAT. Then there's the labour at £105 +VAT per hour.

The head of service told me that in all his experience he only ever heard of the control module blowing (under the GSM antenna). He said if this component goes, then several things happen.....The range for the remote locking is drastically reduced (although the infra red eye in the drivers door still works) and the radio reception is non existant. Neither of these are apparent with my car, except for occasional slight hiss on radio reception.

The only option they are offering, is to have the fault properly diagnosed. They admit this is vitually an open cheque book. I can limit the amount of time they spend but, they still suggested minimum 3hrs.

You can see where this is going.......north of a grand!!!

As GTEvo said, if the external antenna looks fine, maybe the internal pad has started to detact. Is it adviseable to see if its a little lose and maybe put some glue down there?

Any ideas?

 

[Diesel Benz]

EPC should tell if your car has an antenna compensator. PM your VIN for someone with EPC access if you do not have yourself.

I did not check where the compensator would be in your car, you could check it from the car if it is easily accessible.

I don't know which parts the module at the antenna would have but it would not have anything else for the GSM antenna except perhaps some passive coupling or filtering components, likely a straight connection. If it has a GPS antenna integrated, it would have a preamp for that, perhaps some other parts for other purposes. Who knows if some solder contact could still be an issue.

I've once installed a glass-through GSM antenna, if the device on your car is similar, then it probably would be possible to glue it again, if the hidden part has lost contact. But if it has, the signal should be pretty close to zero. But it could be pushed by a panel or something and then losing proximity at times...

I assume you don't have IR reflecting glasses in the car. In that case even an after market antenna at a decent place in the car would do (if you don't drive a lot at very poor network coverage areas, I would assume you cannot find those from the UK). Better than a huge bill from fixing the OEM set-up, but I wouldn't give up with that one yet.

 

[The Dent Guy]

EPC should tell if your car has an antenna compensator. PM your VIN for someone with EPC access if you do not have yourself.

I did not check where the compensator would be in your car, you could check it from the car if it is easily accessible.

I don't know which parts the module at the antenna would have but it would not have anything else for the GSM antenna except perhaps some passive coupling or filtering components, likely a straight connection. If it has a GPS antenna integrated, it would have a preamp for that, perhaps some other parts for other purposes. Who knows if some solder contact could still be an issue.

I've once installed a glass-through GSM antenna, if the device on your car is similar, then it probably would be possible to glue it again, if the hidden part has lost contact. But if it has, the signal should be pretty close to zero. But it could be pushed by a panel or something and then losing proximity at times...

I assume you don't have IR reflecting glasses in the car. In that case even an after market antenna at a decent place in the car would do (if you don't drive a lot at very poor network coverage areas, I would assume you cannot find those from the UK). Better than a huge bill from fixing the OEM set-up, but I wouldn't give up with that one yet.

Cheers Diesel Benz

I dont know if i have IR reflecting glass - i assume not.

And Im sure i dont have access to EPC (whats EPC?)

Can anyone with EPC help if i PM my VIN?

 

[martin grimmer]

Hi
if its any help my w203 facelift coupe has had a similiar problem when i purchased my car i noticed the radio freq was intermittent and the ultrasonic remote did not work, however the UHI phone and signal did. the problem with my car was Mercedes had a bad batch of glue in there Bremen plant during the manufacture, this glue was used to adhere the probes to the rear screen for the remote alarm amp and the radio aerial. this glue fault resulted in the probes coming away from the aerial causing the problems, if you lift up the hatch look at the top where the roof meets the rear glass and look behind the cover you might find what i did the probes hanging there detached from the glass causing the problem.
in terms of repair the cost of the new amplifier was around £85.00 plus fitting however if this is not done by a MB dealer you can damage the rear windscreen contacts which result in a replacement screen which is £156.00 plus installation, like i say it can be done without replacing the screen but the fitters need to have done it before, the MB dealer i had repair mine messed it up resulting in a new screen totalling a cost of over £600.00+ inclusive of labour but i was lucky my nearly new merc coupe was under warrenty good luck hope this helps

martin

 

[The Dent Guy]

Update 3

It's fixed :bannana: ....... and for free too!!

Many thanks to all who helped but, HUGE thanks to both Richard and Diesel Benz

Despite MB main agent saying i didn't have a compensator, with a little help from my friends above, i discovered i do have one. And sure enough, when i disconnected the 2 co-ax cables and plugged them directly into each other, (by-passing the compensator), it works fine - even with as little as 1 bar of signal.

The compensator is under a plastic cover (bolted down) just behind the rear seats on the boot floor. I've attached 2 pics - one is close up, for all to see the location and the co-ax now by passing the unit.

If the part is no longer fitted (since 2006) then i figured i dont need to replace it. Just priced up a new one from the stealer.......wait for it........... £299 +VAT

Thats £351 to replace something that isn't needed.

Thanks guys.....really appreciated the help.

 

[richard]

It's fixed :bannana: ....... and for free too!!

Perfect !

If you're in that part of the car again, i'd disconnect the power from the compensator also. Just because youre not using it, so why power it.

[edit, my comment below only applies to pre-facelift]
if you ever need to replace on on a pre-facelift, ask me - theres a B6 xxx xxx xx part you can buy from dealer, which consists of that plus a W203 complete phone loom thats a stack cheaper than the compensator on its own!! - It was for retrofitting compensators, the idea was you needed to take 1 piece of coax out of the new loom (to go from the compensator to the antenna) and bin the rest of the loom !!!

R

 

[daveyjones]

could anyone tell me i have a clk 2004 with no radio reception,i know that the radio is fine ,i also know that the airal amp is located by the rear window. my problem is that before i owned the vehicle the rear screen must have been replaced because now the amp is no longer fixed to the rear glass.my question is could someone tell me where the correct place to secure the amp or is it trial and error. please help it's driving me mad