Speedometer/tachometer not working on m50b25 swapped e30.

[angelolotino]

Recently bought a 1987 325is that already had the m50b25 motor swapped in. Runs and was able to get it home but the speedometer nor the tachometer worked (needles aren't moving), while everything else on the dash seemed to run fine. I messed around with the speed sensor in the differential and replaced a blown fuse in the fuse box but I haven't been able to test if the speedometer works yet, but the tachometer still doesn't seem to move. I've been looking through the forums regarding the tachometer and found a couple mentioning c104 in the glove box having relation to the tachometer. When I went to go look I noticed I had a green BOSCH 0 261 200 403 ECU and remembered that people have been using the red BOSH 0 261 200 413 ECU on these swaps. Would that be effecting the tachometer from not making any movement? Also, the only time I saw the rpm needle-moving was when I tried to start the car on a dead battery.

Any information helps, thank you!

[e30strokr]

best way to start is find a spare cluster...see if its not that instead of looking for electrical gremlins..... I bought clusters that did not work at all and needed solder reheating

[ForcedFirebird]

In the glove box there's a white three pin connector. Three wires are on there, yellow is the fuel economy gauge, green is drive-away protection (code on the OBC), black is the tachometer.

Many times when people swap early models, they forget to hook up those wires.

The 403 DME is non-vanos, 413 is vanos

[angelolotino]

In the glove box there's a white three pin connector. Three wires are on there, yellow is the fuel economy gauge, green is drive-away protection (code on the OBC), black is the tachometer.

Many times when people swap early models, they forget to hook up those wires.

The 403 DME is non-vanos, 413 is vanos

Found the fix! Thank you for mentioning the colors aswell, made it much easier.