Some one know how speed signal is on 312D 1997? im thinking about up to speedometer cluster, is it same as Can and obd? or is it only power going from wheel sensor-ecu up to cluster?
im thinking to make a new digital speedometer cluster...
Nonono... Thats not a t1n....Victor,
It may not even be electrical, let alone CAN!!!
Reading page 94 of the old service manual here...
It states to remove the Gearbox disconnect the mechanical speedometer drive cable.
SO first place to look would either be on your gearbox or on the back of the speedo head for a drive cable.
omg! what a job u did for me there! tnx a lot!Fascinating....
i'm only starting the dig, butyou (theoretically) have a 1-day/2-drivers recording tachograph, ABS and ABR, 4-wheel drive and "basic fittings for a radio" (so you may have the speed-pulse signal presented on a connector)
Here's your datacard: View attachment 91412
Oh, what fun.... here is the schematic and legend for your instrument panel: View attachment 91413
(yes, the MB stupid software issues the pages in backwards order... "cut and tape")
The sensor for the speedometer is item G4 at (lower horizontal scale) location 76.
(engine RPM is B72 at location 60)
Connector X41 is the speedometer connector, and X49 is the speedo calibration and seal connector.
(note that X49 shows up elsewhere)
((i thought that the fuel level sensor (B3) came in X41 at location 46, but that's really X4.1))
The "tachometer sensor" can enter by either X41 or X49... so you'll have to look at yours.
The drawing says that X41 is only a 2-pin connector (with twisted wires to the sensor)
X49 has many pins (note the zig-zag line on the edge of the shell, indicating "more elsewhere")
"tachometer" is the generic term for anything that measures something rotating.
Wire color codes are in German, so "sw" (swartz) is Black.
The speedo sensor looks like a simple coil pickup (i'm trying to find it elsewhere)
Found it: it's MB part number A 005 542 58 17 "sender unit, speedometer"
Item number 53 in the diagram below my signature (scroll all the way down for the image)
((the drawing hints at a 4-wire cable))
M111 (not listed in the Legend) is the engine wiring harness
Given the datacard, here's the schematic for the "flat tachograph": View attachment 91417
Here the (a?) speed sensor seems to be G3, but the "speed sensor connector" is J149 at location 12, which corresponds to the mess at location 70 on the instrument cluster drawing. I'm not sure if that's an input or output from the IC. (i suspect it's an output from the IC, and that G3 is a redundant/confirming sensor for the recorder)
View attachment 91419
... i think your project will prove very interesting...what do u think about my thought on this?
My pleasure ... i learned quite a bit about the differences in the 1997's way of doing things.and again, thanx a lot for all of youre help!