Temp Gauge HELL

[Royalratch]

Old 318iS owner here, so we’re talking about the mighty M42.

My TEMP GAUGE doesn’t work, stays on ZERO no matter how long I idle or drive. All other gauges / meters / clock lighting work just fine. It does flicker for half a second when ignition ON then stays still.

Here’s what I’ve tried so far to get it to move:

Tightened nut on back of gauge
Grounded Brown temp sensor plug
Grounded Pin 4 of C101
Tried 2 x other clusters

Next thing to try is probably fit a new temp sensor but I can’t see that solving anything given the above? If it was a rotten C191 plug then Grounding Pin 4 should have worked?

Help much appreciated. Car runs perfect but obvs not keen to go out with a faulty temp gauge…

[martauto]

Are you getting any voltage at all going to the gauge ?

Mart.

[Royalratch]

Are you getting any voltage at all going to the gauge ?

Hi. I ‘assume’ yes as the gauge flickers from dead (off the divisions) into the bottom of the blue with ignition on. It just doesn’t move past that.

How to check voltage?

[Royalratch]

I don’t find any sign of a C191 plug, only this junction box, which looks to be clean inside.

[Royalratch]

ONE AT A TIME FFS

[Royalratch]

Are you getting any voltage at all going to the gauge ?

Mart.

Good talk

[martauto]

Are you getting any voltage at all going to the gauge ?

How to check voltage?

A multi meter will do.
The Wiki might give you some idea of how much voltage should be at the gauge.
Brian is your man but he`s in short supply these days.

Mart.

[Royalratch]

Bump

[clivej]

Apparently this can be a symptom of a dead Service Indicator light battery. Can you reset your SI lights?

[Royalratch]

Apparently this can be a symptom of a dead Service Indicator light battery. Can you reset your SI lights?

I’ll give this a try mate - wouldn’t this affect other gauges in the cluster tho?

[clivej]

Yes it can also cause the tachometer to malfunction. That's according to the Haynes manual anyway. There used to be a link on here about replacing the batteries but it doesn't seem to work anymore.

[Royalratch]

Yes it can also cause the tachometer to malfunction. That's according to the Haynes manual anyway. There used to be a link on here about replacing the batteries but it doesn't seem to work anymore.

Doubt it’s this mate, everything else works fine. Fitted new sensor so now it can only be about tracing the break from sensor all the way to the cluster - which will be gross.


There’s appears to be no C191 plugs on M42 engines…