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2003 S500 4Matic

3K views 12 replies 4 participants last post by  louisbr 
#1 ·
Hello All,
I just bought a used Mercedes with 64,000 miles...it runs beautifully, but a few annoying problems.
1. Outside temp reads 140 sometimes, -140 sometimes and no display sometimes. Is it the sensor? Can I change it myself?
2. Trunk lid requires quite a bit of pressure to close. When close, the hydraulic closes it shut, but there is a hydraulic sound for about 20 seconds before the handle goes back in.
3. The middle rear headrest is down, but the other two rear headrests are up and won't go down with the pushing of the button on the dashboard. I hear a sound, but nothing happens.
4. The parking brake handle is unattached from the brake cable. For my car inspection, the station was able to see that the parking brake worked by just pressing enough on the foot pedal, but not up the first click.

Can I repair any of the above items myself? I am not very mechanical.
 
#10 · (Edited)
Thanks much for your detailed response.
I have power assisted doors and trunk, but no power trunk closer....no red button. Holding the headrest button doesn't help. The parking brake pedal is attached, but the plastic release handle on the dash has been detached from the cable. With the temp sensor, I'm worried it could be some other problem since the display sometimes shows nothing.
The sensor sometimes reading nothing and sometimes reading 140 argues the sensor is bad or there is a short in the wiring. I'll bet on the sensor. It should be a cheap fix. It's almost certainly not the display which would be much more complicated. I could be wrong, but I'd start at the sensor end of the chain.

I'm a little stumped with the trunk problem. You have an automatic trunk release, but it doesn't open the trunk full open and there is no power assist to close the trunk? Maybe it's a model year issue; my '04 has soft-close doors and power trunk opening and closing assist as part of a single option. So the trunk latches okay and unlatches remotely, but it's hard to close by hand? Don't know why it would be difficult to close by hand unless you are pushing against the hydraulics that open and close it.

The headrests are also a mystery. Their release isn't hydraulic, it's an electrical switch, I think. Could be a fuse. Shouldn't be overly complicated to figure out and fix.

The parking brake release may be as simple as reattaching it. It may involve replacing a part or two and one end of the cable or the other, but it should be straightforward. It's a mechanical piece; no hydraulics or pneumatics involved.

I'd find an indie shop that specializes in MRZ cars. Shouldn't be hard in your area. Let them trouble-shoot the problems. I really don't think they are going to be expensive fixes. None of those problems are likely symptoms of some sort of massive electronic systems collapse. A couple of hundred bucks and you're back in perfect shape.

I see you have a Silver Arrow as well. The R129 forum on this site is very friendly and very savvy about the R129 chassis. People will want to steal your SA, but you'll get lots of good advice from them.

Did you take my advice and check in with the W220 forum? They may have a $10/5 minute fix on the tips of their fingers. I would check there rather than this forum anyway; the W220 is not common enough that readers of this general forum would necessarily be able to help. It is also the flagship car, so it usually gets new electronics and drivetrain changes first so people will smaller versions may not be familiar with the new stuff.
 
#11 ·
The sensor sometimes reading nothing and sometimes reading 140 argues the sensor is bad or there is a short in the wiring. I'll bet on the sensor. It should be a cheap fix. It's almost certainly not the display which would be much more complicated. I could be wrong, but I'd start at the sensor end of the chain.

I'm a little stumped with the trunk problem. You have an automatic trunk release, but it doesn't open the trunk full open and there is no power assist to close the trunk? Maybe it's a model year issue; my '04 has soft-close doors and power trunk opening and closing assist as part of a single option. So the trunk latches okay and unlatches remotely, but it's hard to close by hand? Don't know why it would be difficult to close by hand unless you are pushing against the hydraulics that open and close it.

The headrests are also a mystery. Their release isn't hydraulic, it's an electrical switch, I think. Could be a fuse. Shouldn't be overly complicated to figure out and fix.

The parking brake release may be as simple as reattaching it. It may involve replacing a part or two and one end of the cable or the other, but it should be straightforward. It's a mechanical piece; no hydraulics or pneumatics involved.

I'd find an indie shop that specializes in MRZ cars. Shouldn't be hard in your area. Let them trouble-shoot the problems. I really don't think they are going to be expensive fixes. None of those problems are likely symptoms of some sort of massive electronic systems collapse. A couple of hundred bucks and you're back in perfect shape.

I see you have a Silver Arrow as well. The R129 forum on this site is very friendly and very savvy about the R129 chassis. People will want to steal your SA, but you'll get lots of good advice from them.

Did you take my advice and check in with the W220 forum? They may have a $10/5 minute fix on the tips of their fingers. I would check there rather than this forum anyway; the W220 is not common enough that readers of this general forum would necessarily be able to help. It is also the flagship car, so it usually gets new electronics and drivetrain changes first so people will smaller versions may not be familiar with the new stuff.
Thanks again for all of your suggestions. I just joined the Forum yesterday and still don't know what I am doing. I did post a thread on the W220 Forum but have gotten no replies as yet. I also took your suggestion and updated my profile, which up until then, I didn't know there was a place for that. Once I get this car in good order, I'll check out the R129 forum. I'm in Florida for a couple of weeks, but when I get back up North, I'll check with an indie shop.

My trunk actually opens fine....with the key, with the remote and with the button on the door. There is only resistance when closing it. At least I don't have to worry about it falling on my head. Maybe it has something to do with the springs. Could they be gas springs? Could they only have a problem in one direction?

I will try to start with the sensor for the ambient temp fix. I can see the sensor in the bumper grill by the driver side headlight, but I don't know how to get at it. On my SA, it was easy....the grill piece just popped out, and the sensor was attached to the grill, and the wiring just plugged into the back of the grill. I don't think the grill piece on the S500 pops out.

On the headrests, I'm hoping that someone can tell me how to release the rear headrests without the switch working. I would just make sure they stayed down in the future.

With the parking brake, the plastic handle is in its track on the lower part of the dash, but I can pull it all the way out since it's not connected to anything. It doesn't appear to have anything broken on it. With a flashlight, while the handle is out, I can see what looks like the cable parts that should attach to the handle. However, I'm afraid to go in there with pliers to try to pull it out in order to try to attach....I'm afraid I'll pull too hard and snap the cable.
 
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