SL/R129: 1992 R129 300SL



I picked up the car from the previous owner. Drove it home, 50 miles . Basically everything worked: Both Heated Seats, Cruise Control, Radio, Both Power Windows, Heat, Air Condition, Rear Window Defroster, etc. No lights on the dash. All seemed well. EXCEPT, I went to the car wash. The car went through fine. I put the car in park. (Left it running), as they vacuumed. When they were done, I got back in, & put the car in reverse, to back out of the spot, & IMMEDIATELY, the ASR, the ASD & the Snow Chains lights lit up!
I am not concerned; it was maybe a coincidence? Maybe the car does need front brakes? I have not brought the car to my mechanic (good friend) yet. But I always think it is good to "know" a little something beforehand. Since this is a 25 year old car, the dash lights are not the same as todays Mercedes. (My everyday drive car is: 2014 E250 Bluetec 4Matic)
Another friend told me that the "Snow Chains Light" not being able to be turned off, is a Transmission problem. He says, that will not let the car shift into 5th gear. Is that true? Again, I will have my mechanic look at the car next week or so.
Any help you can offer is certainly appreciated!
Start the car and drive-off with the gear shifter in position "4". Attain a steady speed of 50+ MPH. Now propose a bet on whether the transmission will upshift to 5th gear when you move the shifter right to position "D". If he asks for odds, give them. Risk dollars to quarters or even nickels if necessary.



You are in New Jersey -- a state that has legalized gambling. Here is an idea. Get this friend to accompany you in your SL for a brief experiment.
Start the car and drive-off with the gear shifter in position "4". Attain a steady speed of 50+ MPH. Now propose a bet on whether the transmission will upshift to 5th gear when you move the shifter right to position "D". If he asks for odds, give them. Risk dollars to quarters or even nickels if necessary.
If you have lost 5th gear, then I would begin diagnosis by reading codes from the transmission ECU. Depending upon codes that were found I might remove the electrical connector to that ECU and check input signals with a multimeter. On the chance that all the problems you have described are somehow related to a single cause, then I would troubleshoot the transmission problem first, since for me its diagnostics are simpler.



Yes, my mechanic (friend) will read the transmission ECU. I know it's probably (hopefully) minor.
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I have not "fixed" it yet, because it is the winter, & it is not driven in the winter.
However, Spring is coming up really quickly. So I would love to get it taken care of ASAP.
Thanks very much!
Joe
This is the part, it is under a screwed on big black plastic cover on the right hand passenger side firewall Right by the hood hinge - When I go out later Ill take a pic of the cover for you to show you where it is.
here is the location, Its one of these two modules if i recall correctly..this is an internet pic i found
Typically, the transmission starts in 2nd gear. But if the vehicle is at rest and the shifter is moved to "2", then the transmission shifts to 1st gear. It remains in 1st even if the shifter is subsequently moved to one of the other forward-gear positions.
Back in the day Mercedes rationale for the 2nd-gear start included reducing "creep" at idle and improved fuel economy.
Typically, the transmission starts in 2nd gear. But if the vehicle is at rest and the shifter is moved to "2", then the transmission shifts to 1st gear. It remains in 1st even if the shifter is subsequently moved to one of the other forward-gear positions.
Back in the day Mercedes rationale for the 2nd-gear start included reducing "creep" at idle and improved fuel economy.


