98 500SL SRS Light

[OU1954]

I have a couple of days to decide on buying a 98 500SL with about 85,000 miles on it. The car looks and runs very clean.

What's the worst thing I can expect with respect to the SRS Light?

Thanks,

DAW

[joeym7]

Hi Is the SRS light on ,if so have the veh systems checked for codes,in all the modules.The thing you want also to look out for is ,if the veh was in a crash,were the air bags deployed and if so were they replaced along with the SRS control unit,which on your veh is very exspensive.Thats why its always good to have a buyer check out done so you know what your in for,and the systems checked,it could need just a clearing and or reseting of the module.joeym PS Did the owner have a recorded work history of the veh and did you have a carfax done.It might even be a good idea to have a body shop check it over ,normal charge is about 55 dollars but worth it on this high end veh

[OU1954]

Thanks,

I do have a clean carfax for the vehicle, it was apparently leased by a Doctor who put most of the miles on it, then my son-in-law bought it about 3 years ago and has only added 7,000 miles. He is out of town at the moment but I can find out from my daughter where he had the car serviced. I have had a good look at it mechanically and it clearly has never been in a crash. What I don't know is how long the light has been on.

I do know that the service person has been trying to buy the car so he can "trick it up a bit" and re-sell it, which is a good sign in my opinion.

I think that here in San Diego, Autozone will do a scan, not sure yet.

My wife has a 99 320 ML and we have no intention of going anywhere near a MB dealer.

Her last visit there, for an oil change, cost about $1,300 including replacing windshield wipers I had just replaced. We got the cost reduced but not much. They replaced the front brake pads and they were a long way from making contact with the warning contacts.

So, assuming there has never been any trauma to the car, I guess the only thing to do is find some place to run a scan on it. I have a simple scan toll for my Vette and other GM cars but nothing for MB.

Thanks,

DAW

[jdkirkk]

"Her last visit there, for an oil change, cost about $1,300 including replacing windshield wipers I had just replaced. We got the cost reduced but not much. They replaced the front brake pads and they were a long way from making contact with the warning contacts."

I recently acquired a very nice '96 SL600 w/34k and have considered taking it to a local MB dealer for routine oil changes. I have an excellent independent shop for mechanical stuff but it is not very convenient. Did you specify "just an oil change" and how did the bill get so high? I have experience with BMW dealers and assume the Mercedes dealers are equally bad, but surely they could be trusted to change the oil?
Thanks.
John Kirkman
Munster, IN

[bill streep]

As joeym points out, the computer on this car is staggeringly expensive. Have it checked out before you buy. A good deal could easily turn into a bad one.

[OU1954]

Well, by now I've had the car about 3 months and have done a lot of little clean-up items on it, just little plastic parts, all fluids are changed, new strut mounts, etc.

The remaining item, one I am not sure I can do myself, is the SRS light being on. A CAN diagnosis reports an intermittent connection to the child senser in the passenger seat. That causes the SRS light to come on when someone sits in that seat, but it goes out after two or 3 start-run cycles with no one in the seat.

Anyone know how big a job it is to get to that area and look at the connector?

Thanks,

DAW :(

[joeym7]

Hi Daw If there is a problem with the child seat recognition sensor ,its a big job on your SL ,the seat needs to remove from the veh and completely broken down alot of different size screws-bolts-wire harness,but most of all reistalled in the same way.I would recomend a copy of the complete job with pictures.Iam glad it eas not the SRS mudule as on yours and most MBs is very expensive. It usually takes a can test to verify the sensor problem,did it show up as a code,also make sure there is not a plug loose on the undercarrage of the seat common problem.Did they lat you know if you are to have no children in the seat ,thet can take the system out of the loop.Joeym

[OU1954]

Hi Daw If there is a problem with the child seat recognition sensor ,its a big job on your SL ,the seat needs to remove from the veh and completely broken down alot of different size screws-bolts-wire harness,but most of all reistalled in the same way.I would recomend a copy of the complete job with pictures.Iam glad it eas not the SRS mudule as on yours and most MBs is very expensive. It usually takes a can test to verify the sensor problem,did it show up as a code,also make sure there is not a plug loose on the undercarrage of the seat common problem.Did they lat you know if you are to have no children in the seat ,thet can take the system out of the loop.Joeym

Thanks,

The CAN test reports the following:

on 12/2/05-
AB
031 Fr Passenger seat occ./auto.child.seat recog.sensor B48
028 Communication between seat and child seat

on 03/18/06 (different repair shop)
AB
31 Component B48 (Front passenger seat oddupied and child seat recognition) is faulty
28 Fault in communication between component B48 and component Chnild seat

on 03/20/06 (same shop as above)
AB
31 Component B48 (Front passenger seat occupied and child seat recognition) is faulty.

The difference between the tests is that the SRS light may go off if the car is driven through several drive cycles with no one in the passenger seat.

I was told by the first shop that it was a complex problem.

If it can be solved by checking a connection I'd like to know how to do it. My MB Service DVD for M129 doesn't have much information about much of anything. It does give a lot of wiring diagrams, but they are, for the most part, too small to make any sense.

Any thoughts would be appreciated.

Thanks,

DAW :p

[ALUEB]

Both My Mercedes cars are preowned. My 99 C280 I bought from a dealer in CT. It was Starmarked and had 22K miles on it and still have over a year of original factory warranty left. So I just bought it. I has been 4 plus years this month I bought it and except for maintenancd I had 3 warranty claims. a broken turn signal lens, wouldn't pass Mass state inspeciton, a new MAS and a new O2 sensor. The only "problem" area is the battery, I am on my third battery, in four years. Part of that problem however is mine, as I have a physical handicap and don't drive long distances like I use to. Also, these cars, never really shut off. the computer is monitoring the car 24/7 whether the engine is running or not. I got a trickle charger with an auto shut off feature. But I forget one day to unplug it from the wall socket, tripped a circuit breaker and bent the plug no big deal.

My 79 SLC is a different story. the seller an MBCA member. Lived 120 miles from me. My son drove ime over the first an second time. The car was in very good condition but did need some work. It had ACC type 2 HVAC problems, those old servo's are problematic at best. The owner had all the service records dating back to 1990 and most of the work was done at a MB dealer. Including a top end rebulid of the engine, rebuild of the auto tranny. My son and I test drove it on the first and second visits. Bought it on the second. I drove it back to Chicopee, Mass and it ran well, a bit sluggish for a hugh V8. But the previous owner only drove it 5K miles since having the engine and tranny rebuilt in 95. But he faithfully change the oil every 3 months and the tranny fluid every 2 years. Also for the price I paid, I had a lot to work with. Two days after I bought it I took it to the mechanic I use. He went over the car and it needed very little work, new calipers. pads and rotors in the rear, and new pads up front. adjusted the steering wheel as it was off center and replaced the shifter bushing with the proper metal ones, and slowed down the cold idle a bit.

I put new tires on it today, as the tires on the car were 10 years plus old and dry rotted. I drove it like that since October of last year. It also needs new door, window and trunk weatherstripping. But the most important thing is it is mechanical sound. The V8 purrs, gas mileage is bad, even with new plugs, and cleaning the TB, accelerator linkage, new plugs, checking the timing etc. I had the servo fixed for less then $100 dollars, heat works great. But the AC is luke warm. And it is R12, so a conversion is in order.

Why am I telling you this story? I normallly wouldn't buy a 26 plus year old car like this. But follow the advice the other posted wrote. But with all the info he had and the look ofthe car and the owner had a honest and forright attitude, and he took care of the car very well, I bought it.

As I said follow the advise the other poster mentioned. I took a chance nd got lucky. Yes, I spent about $2k plus so far, but it is a old car, and I have collected some cars newer then the 450SLC that I had checked out and were give a clean bill of health and later spent thousands on repairs.

The best part is, you drive this car, not point and steer like new cars. That alone make it all worhwhile! Good Luck

[joeym7]

Hi Daw IT easy to diagnose the pass seat child recognition sensor,with a scanner like MB or an AST that has live actual reading,it can be tested with and with out some one in the seat,along with a resistance reading,this way you can tell if its the wiring or the sensor it self.I have replace many seat sensor in your type of SL ,did not find many with a loose or bad connection,and as I said prior its a tough job,I would advise getting help,yet get a clear diagnoses first,also check the price of the sensor from the dealer,I believe their the only one you can get it from,if some one knows were else please step in.Joeym

[OU1954]

Hi Daw IT easy to diagnose the pass seat child recognition sensor,with a scanner like MB or an AST that has live actual reading,it can be tested with and with out some one in the seat,along with a resistance reading,this way you can tell if its the wiring or the sensor it self.I have replace many seat sensor in your type of SL ,did not find many with a loose or bad connection,and as I said prior its a tough job,I would advise getting help,yet get a clear diagnoses first,also check the price of the sensor from the dealer,I believe their the only one you can get it from,if some one knows were else please step in.Joeym

The only diagnostic tool I have is the one from Autoengunity and it is not MB specific. Tell me about the other tools.

The scan readings I reported earlier were from two different independents, one in December, and the later two from another shop where I now have my work done.

By the way, this second shop is into desert rally racing and is building the engine (based on a BMW) for a Russian car designed for the Dakar rally next year. I'll be going out to the desert to photograph the test runs in the next week or so. Since Dakar is over for the year, the car will be going to other rallys, but unfortunately not in the U.S. so I won't be there for those runs, just the local testing.

I have snapshots of the car and engine and if I can get releases from the car and engine builders, and the owners of the car, I can make them available.

DAW :o

[joeym7]

Hi I would find a local shop that uses a AST or Baum scan tool they have a MB specific software for them.I prefer the AST has more features then the others,the one I do not like is the snapon,its limited.The good news is you have a 1998 so you do not need someone with the latest very expensive version due to the on board central gateway in 2005 and up.Last time I did a SRS light read out at the dealer it was about an hour labor for codes and printout and reset.The cost will get high if they have to trouble shoot due to a problem other then a part comming up,like a wiring problem.Good luck keep us posted.Joeym