94 325i tach issue

[gtpike]

I have a 1994 325i convert. My tach and mpg meter have stopped working. I recently changed the spark plugs, started up the car, and the revved the engine. The tach was working fine. Next I disconnected my battery to clear a check engine code in my ECU. I have disconnected and reconnected the battery before, and never had a tach problem. However this time when I reconnected the battery, the tach stopped functioning. Did I do something wrong and what can be done to regain my tach functionality?? Thanks for the help

[Jeron]

Make sure you reattached all of the ground wires when you changed the plugs. Check for water in the ECU compartment.

I think you can disconnect the battery cables and hold them together for a few seconds to reset the ECU, but you should get a second opinion before trying it.

[gtpike]

Update: I rechecked the ground wires and all were reconnected. Now the temp gauge does not work at all either, which is a serious problem. I have not checked for water in the dme, but what I don't understand is how disconnecting or reconnecting the battery could have cause this problem...unless it was one serious coincidence..