SL/R107: Speedometer not working while Odo works fine
Thread Starter
Newbie
Joined: Aug 2022
Posts: 4
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380 SL 1985
Speedometer not working while Odo works fine
Hello, on my 85 380SL, 75 000 miles, the speedo stopped working 2 or 3 times while driving but was eventually coming back on at the right speed indication. I removed the cluster panel to change some bulbs and check if the wire was well pined and a little bit after reinstallation, the speedo stopped working for good while the odometer keeps on rolling fine. On my old 964, the speedo was going down to zero if the ABS was faulty or any other major security issue was detected. I have no ABS on the Benz but do you know if some similar could happen. I can't understand why the speedo would not work while the odo does...
Many thanks for any advice.
Many thanks for any advice.
Junior Member
Joined: Jul 2020
Posts: 70
Likes: 11
From: Monroe, GA
1985 380SL
I dont have any direct experience with speedometer issues, I have only replaced gears in the odometer in my car. Attached is some technical info on the electronic speedometer that may help you diagnose your problem.
The 85 380SL does have ABS brakes standard, but there is no connection to the gauge cluster other than the warning lamp.
The 85 380SL does have ABS brakes standard, but there is no connection to the gauge cluster other than the warning lamp.
Thread Starter
Newbie
Joined: Aug 2022
Posts: 4
Likes: 0
380 SL 1985
Thank you very much. I am going to check the fuse first !
Actually, the cruise control is innoperative, there might be a link to the faulty speedometer ?
My ABS is definitely not working on this car given the amount of gum I left on the road at my last emergency brake ;-), but I think I read I have a faulty speed sensor on the report.
I guess I need to check all this too...
Actually, the cruise control is innoperative, there might be a link to the faulty speedometer ?
My ABS is definitely not working on this car given the amount of gum I left on the road at my last emergency brake ;-), but I think I read I have a faulty speed sensor on the report.
I guess I need to check all this too...
Thread Starter
Newbie
Joined: Aug 2022
Posts: 4
Likes: 0
380 SL 1985
Thank you very much. I am going to check the fuse first !
Actually, the cruise control is innoperative, there might be a link to the faulty speedometer ?
My ABS is definitely not working on this car given the amount of gum I left on the road at my last emergency brake ;-), but I think I read I have a faulty speed sensor on the report.
I guess I need to check all this too...
Actually, the cruise control is innoperative, there might be a link to the faulty speedometer ?
My ABS is definitely not working on this car given the amount of gum I left on the road at my last emergency brake ;-), but I think I read I have a faulty speed sensor on the report.
I guess I need to check all this too...
Junior Member
Joined: Jul 2020
Posts: 70
Likes: 11
From: Monroe, GA
1985 380SL
My car also had no functioning cruise control or ABS when I got it. A common problem for the cruise control is the circuit board that controls it. The solder joints come loose, but can be re-soldered. See the video here:
. I did this on mine and the cruise control now works normally. On your car, a non functioning speedometer may also be a cause. The cruise control receives its speed signal from the speedometer, which in turn receives its signal from the sensor on the tail of the transmission. Perhaps re-soldering the connections on the speedometer circuit board could fix yours.
The most common failure in the ABS is the front wheel speed sensors. These are no longer available for the '85 and older cars, but a Volvo sensor can be modified to work. I did this with my car and I now have a functioning ABS. I have attached a document with the details.
The most common failure in the ABS is the front wheel speed sensors. These are no longer available for the '85 and older cars, but a Volvo sensor can be modified to work. I did this with my car and I now have a functioning ABS. I have attached a document with the details.
