Rear sunshade; 95' S 500 Coupe

I just bought a 95 S 500 coupe and the rear sunshade has worked fine until today. It is stuck in the up position. If I turn everything off and press the switch I can hear a faint sound when I press up or down. The sound is not like the motor running. Any ideas?

[KenP]

First, congrats on buying a beautiful auto... I have a '96 S500 Coupe that I've had since January. And, I see this is your first post here... welcome. You'll find this forum to be the very best. Lots of help here from both techs and DIYs.
I'd recommend you also subscribe to ALLDATA online service. You won't find a service manual in hard copy for the W140s (at least I haven't been able to). ALLDATA is fairly inexpensive... its about 25 bucks a year. The organization of the data isn't particularly intuitive, but most stuff is there if you look for it. The rear sunshade is listed under "Windows and Glass".

I've not had my sunshade apart (Mercedes calls it Sunguard), but your problem is either in a faulty Sunguard unit or lack of power to the Sunguard. Be sure to check all your fuses.

Doesn't look too bad to get to... you have to remove the rear shelf. Once you do that, the connector for the Sunguard looks like its on the end of the unit, on the driver's side. If you unplug there, you can operate the switch and see if there's power.
IF there is power, the unit is likely bad. It comes out the top after removing three nuts from the trunk side.

Good luck. Hope this helps. KenP

[wjm]

Hey michiganBenz. welcome aboard. Where in Michigan are you located?

Thanks Ken for the advice. I will try Alldata. I have checked the fuse and it is good. Plus I can hear some faint sound when presssing the button, so I am pretty sure it is getting power. The service manual question was something I was wondering about since I see that they are available for so many other models. With as complex as an S 500 is it is amazing that there is not a printed version out there. I do have a one year Starmark base waranty but I don't think it covers the sunshade. I am going to check just to be sure. I have joined the Mercedes Benz Club of America and I hope that I can find resources of information from them as well. I do have one other problem, the passenger seat belt extender sometimes keeps going in and out when driving without a passenger in the seat. I now leave the belt buckeled since this was driving me crazy. Sometimes it would not do it at all, it would stay in like it should and other times it would go in and out. Have you had any problem with your passenger extender? I live in Ferndale, MI

Thanx,

Chris

[KenP]

Chris,
Hi. Delighted to meet you.
I've done a pretty thorough job hunting for information on the W140 Coupe... there's not much to be had from normal sources.
I don't think you'll get much assist from the Mercedes Club as far as documentation, etc. Nobody I have found sells manuals for these cars.
The three best sources have been this forum (there are several Coupe owners and excellent techs here), the ALLDATA subscription I have, and a set of original Mercedes Parts Microfiche for the W140C that I scored off of eBay. Between the three, I've managed to muddle through everything so far. The ALLDATA site allows you to download and print the pages you need for quick reference later... really handy when checking electrical schematics.
Lest I forget, there's alot of info on JimF's site. (Sorry Jim!)

http://pages.prodigy.net/jforgione/MB_S500.html

You'll also find Phil of the Partsshop related to this site as very knowledgeable and willing to find parts for you at fair prices. The good news is that most of the powertrain and suspension parts for your car are the same as the big sedans. There are lots of those, so used parts can be had. The bad news is that anything unique to the Coupe is usually hard to find... and expensive. Try pricing a headlight! The Coupes are pretty rare, there aren't many in wrecking yards. Heaven help you if you need a hood. None of the body parts will interchange with a sedan.

I haven't had any issues with my seat belt extenders; they work fine. Don't think its a terribly complex system so shouldn't be too awful to troubleshoot. Sounds like the sensor that tells the unit the car door has opened/closed is intermittent.

Anyway, let us know how you make out. I've been pretty much all through my car doing standard stuff... so, if I can help, post here or write me at gearhead285@hotmail.com
Not many of us W140 Coupe owners... we gotta stick together!
KenP

[JimF]

Welcome, Chris to the best site in the world!

Your coupe is one of the rare ones and you will enjoy it.

Re the sunshade: saw my tech 'rassle' with one last month. . . everything was apart. My coupe doesn't have one

Refer to my page (click 'www' icon below) and it may help you fix something if it evers quits.

Thanks Jim for the tip about Alldata, the info there is great. They say that in order to remove the rear shelf I have to remove both rear seats (tops and bottoms) and the c-pillar moldings. What a pain! I have not had the time yet so for now it just stays up. I want to also say hello to Jim, I have seen your site and I think it was your site that lead me to this one. Lots of great stuff there!

[royaiii]

Had the same problem in my 99 S420. Sunshade was stuck in the up position. I had it fixed under warranty and the advisor said that it was a very intense repair and they broke some other part while trying to fix it. I would suggest taking it to the dealer and have it fixed so that if they break any part while fixing it; it will be their problem.

[jkmmrs]

This is slightly off-topic, but it's encouraging to see some discussion on the 140 coupes - I have a 94 S600 coupe with about 46k miles. Anyway, two questions for the group:

1) Has anyone attempted to replace that activated charcoal filter that's somewhat buried and costs over $300 for the part alone? I hardly ever press the switch to filter out bad smells, so not sure if this replacement is even worth bothering with.

2) Anybody had to replace their catalyctic converters? Mine seem to be corroding, altho the rest of the exhaust system looks fine. Is this a DIY job?

Thanks

Jay

[royaiii]

1) No I haven't attempted to change my filter as I think the part is buried in the dash. DIY jobs on a W140 are limited to simple maintenance procedures. Also DIY on a W140 may lead to breaking a small fitting that requires replacing an entire assembly.
2) On my S420, I had both cats replaced, center muffler, rear muffler replaced at around 45k miles because of a sulfur smell. In addition I had the MAF sensor replaced + O2 sensors. I think the best way to have the system replaced is by a muffler shop who can do the job right. Also, it is imperative to have the Mercedes or OEM cats installed as a simple electrical hickup can lead to spending thousands on diagnosis and repair. Having a lift is necessary for this job, wouldnt attempt to do this on stands. I woudnt change the cats for looks alone unless they have a functional problem.

[JimF]

you have a lift!!! My tech is kind enough to let me use one of his lifts so it takes the sting out.

The charcoal filter is one of those jobs but it doesn't need a lift! My car had about 98K when I changed it, about 1 year ago. The filter wasn't that bad but was very dirty.

The pre-filter (also charcoal) located on top of the blower is one that should changed. It's also a little pricey also but is a key filter. Thiss one is easy to get to; 15 min job.

Never have replaced or seen a cat replaced on these cars. I would think that it should last 150K+ miles. This is based on what I see replaced at my tech's shop.

[KenP]

For JimF... hi. Long time no talk. Hope all is well on the left coast.

For michiganbenz ... glad you found ALLDATA useful. I've had my C pillar trims and back seats out... not a hard job at all. To take all that out, all you need is something to pry with (I used a large screwdriver) and a 10mm socket. Go for it.

For jkmmrs... haven't changed cats on my car, but it looks pretty straightforward once you cut the muffler off (Ouch). Bet they're expensive. Wouldn't change unless you believe the cats to be bad internally. My S500 Coupe cats look like stainless steel to me.
Haven't changed the charcoal filter, but STAR magazine ran an entire article on changing it recently... lots of stuff to remove, but very straightforward and you can do it all under the hood. Trickiest parts are taking out the wiper assembly and then having to use a vacuum pump to retract the seal.

For royaiii... couldn't disagree more. The W140 (at least so far) hasn't been bad to work on at all. Its well laid out although very complex. It is certainly not limited to simple maintenance repairs. I can't imagine owning a car I don't work on. I've owned several American cars that are much harder to work on and, frankly, aren't designed to be repaired. My experience with my W140 shows me that most stuff is made to be repaired instead of just being thrown away and replaced.

Regards, KenP