S.I.B. Batteries

[GAZZA3354]

Hiya, i changed the batteries on my 89 318i's service indicator board because the the tacho and the mpg gauge havn't worked since i got the car, but they still won't work!. The original batteries did not leak and the board seems undamaged, any ideas please?

[djsimmy]

same as me. pissing me off i need to find a garage that can do it

[kitch]

Try the connector to the diff/unit in the diff or the cable coming out of the diff, sometimes the vibrations can cause the cable to become brittle and snap inside the insulation.

[E30_Crazy]

Try the connector to the diff/unit in the diff or the cable coming out of the diff, sometimes the vibrations can cause the cable to become brittle and snap inside the insulation.

^^^Pretty sure that would only affect the speedo.

Are your cars facelifts or pre-facelifts?

[Barx325i]

diff sender is only road speed, however the mpg gauge does need a hand with road speed to work out the miles bit

The rev counter is not related to the diff sender no

[E30_Crazy]

On pre-facelift looms, it's a white three pin/wire connector under the drivers side dash. Three wires and a plug come out right from the main ECU plug. The other three wires and corrosponding plug come from farther behind the dash and up over the steering column. Check to make sure no wire have come loose from the plugs, and of course that they are plugged into eachother.

If it's a facelift, then the signals along these wires are fed through the C101 plug to the ECU. If you want to check for continuity up to the C101, it's ECU plug pin 6 to C101 pin 9 (RPM) and ECU plug pin 32 to C101 pin 8 (MPG).

Failing that, I would check the sensors for engine speed. I've just converted from pre-facelift to facelift engine/management, so I'm not sure if it's the front toothed pulley or a sensor on the flywheel or something else.

[GAZZA3354]

Mines a facelift and i'll be checking these items, many thanks for your info