Was working under dash and now tach doesnt work

[NeedaE30]

I was just finishing up putting my interior back together got the lower drivers kick panel back on and each side kick panel on started the car and the Tach and MPG guages now do not work, they worked 10 minutes prior to this i checked the fuses and i have none blown, i removed the cluster, removed all connections and reconnected everything reinstalled cluster, still no tach or MPG, disconnected battery still no tach or MPG,, Is there any wires or connections under the steering wheel above pedals, by the ECM that i could have touched or fucked up that would cause this problem?

temp and fuel work i have 5 green lights on the service indicator check panel works Check engine light does not work and never has since i owned the car.. not sure what do to here it was literally just working then 10 minutes later after installing the kick panels it doesnt work, WTF 27 year old bmw!!

i also tried getting my central locking fixed today, i tried disconnected the drivers side electrical plug that goes between the door and the body that has the reubber seal cover it in the door jam, yea i found it impossible to disconnect this connector infact some of the side edge piece that the rubber grommet goes under has broken off because it was so brittle, i ended up leaving it alone, now my central locking works o.O but tach MPG dont, i dont think this has anything with tach mpg unless some wires for the gauge cluster end up going through the drivers door o.O

[jlevie]

What car? Cars built before 9/87 route the tachometer and econometer signals from the engine harness to the cluster via C104, near the DME connector.

[NeedaE30]

its 07/87 325is

c104? k ill check thanks

[NeedaE30]

trying to find out what this connector looks like, google isnt helping, its under the cluster above the pedals? my ecm is located by the drivers kick panel not in the glove

[NeedaE30]

well every single connector is connected under the dash and i see no broken wires, i am at a loss as to where to go from here i have checked all ground connections in the car have disconnected the battery and replaced all fuses associated with the tach, all connections seem to be where they should be,

the only other thing i can think of that i did was cut out some aftermarket piece of wiring that a previous owner installed and spliced into the headlight switch, it wasnt connected to anything other than the headlight switch so i find it hard to believe that removing this broke the tach, it was working when i stopped the car about 10 minutes prior to installing kick panels and tying to disconnected c405.. i've read that you dont even need an si board to have a working tach so if its the si board why do all gauges work except tach and mpg?, tho-ugh the check engine light in the car has never worked, its not the bulb because that is new, so maybe the cluster is just fucked??

[jlevie]

Unless the car has had it's electrical system extensively rewired, the DME (aka ECU/ECM) will be above the glovebox. The engine harness won't reach anywhere else. C104 is a three pin while Molex type connector. One end is attached to the engine harness with a few inches of wire and will be close to the DME connector.

[NeedaE30]

Unless the car has had it's electrical system extensively rewired, the DME (aka ECU/ECM) will be above the glovebox. The engine harness won't reach anywhere else. C104 is a three pin while Molex type connector. One end is attached to the engine harness with a few inches of wire and will be close to the DME connector.

hmm i guess i thought the big silver computer/exu box looking thing above my pedals was my ecu/ecm/dme guess not, well i didnt go anywhere near the passenger side but i will double check this connector thank you sir

[accident]

That's your ABS module on the driver side.

[jlevie]

hmm i guess i thought the big silver computer/exu box looking thing above my pedals was my ecu/ecm/dme guess not, well i didnt go anywhere near the passenger side but i will double check this connector thank you sir

As accident said, that is the ABS module. If you weren't working under the right side of the dash, C104 is probably okay. That suggests that the connector on the right rear of the cluster has been disturbed, of if the battery was disconnected for a while that the SI board in the cluster died (old batteries).

[NeedaE30]

As accident said, that is the ABS module. If you weren't working under the right side of the dash, C104 is probably okay. That suggests that the connector on the right rear of the cluster has been disturbed, of if the battery was disconnected for a while that the SI board in the cluster died (old batteries).

ok abs module that makes sense thanks for the clarification, i thought it might be one of the connectors on the back side of the cluster either blue or yellow, but i have check , checked reconnected and reconnected some more, all of the connectors on the back of the cluster.. the battery was dead for about 5 months this winter, but when i put a new battery in she fired right up and everything worked, tach was working for a few weeks until i shut the car off, installed kick panels, and tried to disconnect c405.. im friggin confused

[NeedaE30]

figured it out