Temperature Gauge Sensor

[New S Wales 2010]

Temperature gauge stopped working altogether. Suspect the sensor may need replacing but anyone know how to check if it is working ?

The WL-T manual is very helpful on the "Water Temperature Sensor" (two wires) but says nothing about the gauge sensor (single wire). Not even where to find it, although I worked that bit out for myself !

The wiring could also be faulty, so I would like to check the circuit with a test meter. Does the circuit include wires to the ECU or is the sensor simply connected direct to the gauge ?

Any advice welcome as I don't want to change the sensor if the fault is really in the wiring or the gauge itself.

[Driver+Passengers]

The single wire for the dash temp sender should be the one towards the top of the head on the driver's side, yes?

As far as I know it should go straight to the dash, ECU is not involved in that circuit.

You could probe voltage at the contact with the wire in place and the keys on, mine measures 4-7V. Also try removing the wire and then measure the resistance to ground.

Edit: this may help... http://www.g8dhe.net/bwm/bwmanualp.htm?1995/Page_54

[Northern Bongolow]

as matt says just remove the wire, connect this wire to earth and the gauge should read full/hot with the ignition on.
the wire goes over the rocker front edge and can be pulled, or the usual one is the connection to the top of the sender is corroded, quick light clean and spray is usually enough.

3 screws hold the gauge to the clock cluster, these connect to the ness terminals on the rear track, these screws if overtightened can break the guage wires internally that are connected to the screws mounting posts. as a rule of thumb dont tighten the screws too tight as this spins the posts and winds the wires round the posts and snaps them off.

the temp gauge does not go through the ecu.

[New S Wales 2010]

Thanks guys. Great advice.

Shorting the wire down to ground proved the guage was working. Replaced the sensor and now all is fine.

[NickAndLiz]

Which sensor did you use to replace it with? Been driving around, meaning to do this for six months... severely slack... thanks!

[Northern Bongolow]

order from mazda or the bongo shop has them, its the temp gauge sender unit. its the single wire sender and is located under the drivers seat, front edge of the cylinder head if its the diesel.