Water Temp sensor and Fan Sensors

[D2BBA]

Hi peeps,

Following the bursting of a coolant pipe on Saturday im going to fully sort the rest of my cooling system.  First things first though, I need to solve a long standing problem:

My water temp gauge doesnt work (nor does the coolant buzzer).  This aint a biggy as I have a Greddy gauge and a Commander to watch the temps.  Odd thing is my fans dont come on when required either.  I use the AC button for low fans and have a simple fan overide for high speed.  This flattens the battery when left for a while, so its time for a proper fix!:Hammer

Question really is where are the sensors located?  Are they both next to the water pump, behind the SMIC? (green and black conector).  

Also wondering if replacing the thermoswitch for an FC one will help whilst im on?  I\'ve already done the thermostat.  Does the switch help to dictate fan speeds?

Sorry for long post!
Chris

[ro284]

Iv\'e done that thermoswitch mod Chris, if you search Thermoswitch mod by
ro284 it may help,
cheers Bob

[ianelvar]

There are a few sensors for coolant temp and level. The two on the back of the filler neck ( quite a pain to get to ) are the ECU temp sensor, and fan thermoswitch. The one on the front is the coolant leven sensor. The temp sensor for the gauge is on the left hand side of the block tapped into the rear housing. It\'s hidden right by the oil presure sensor. Mine didn\'t work till i fiddled with the white connector between the engine loom and the dash loom, which is hidden right up near the big grommet where the engine loom goes through the bulkhead.

[D2BBA]

Cheers for that fellas!:)

Any idea what I have to strip to get to the back of the coolant neck.  I take it the SMIC comes out, which will be removed to access the thermoswitch anyway.

Ta
Chris

[Frankie]

I\'ve also done the FC thermoswitch mod.  Its quite tricky to get to. You have to remove the crossover pipe, intercooler pipes and the alternator to get at it.  

And you\'ll need a closed end 17mm spanner to take it out as a socket set will not fit.  The space is very limited and the connector and wire will be very brittle.

Pulling the alternator is the most time consuming part and be careful when removing it as there are 2 small oil lines running underneath it.

[D2BBA]

Quick update guys...

Stripped everything down and found that both the ECU temp sensor and thermoswitch on the back of the filler neck are knackered.  Sensor on the front is OK but wiring is shot.  Im going to check the wiring now following Pip at WGT\'s advice.  

I have new silicone hoses, a set of fans and a temp sensor on the way, however I cant find anywhere that stocks a new thermo switch.  Can anyone help?  If I ask Mazda im gonna need a part number too!

Ta
Chris

[ianelvar]

I\'ve got a spare filler neck which should have one attached. Want me to look for you?

[nikp]

Actually - i believe the temp sensor that\'s by the oil pressure sensor is the sensor that\'s used for the temperature gauge.

The other sensor is used for the turning on of the fans.

[ro284]

Rx motors would have a Thermo Chris, My wiring had also broken down from the Thermo and the fans did not come on all all, untill i rewired the feed from the Thermo direct to the Fan relay (no3 i think)
Bob

[ianelvar]

Actually - i believe the temp sensor that\'s by the oil pressure sensor is the sensor that\'s used for the temperature gauge.

The other sensor is used for the turning on of the fans.

Very true, but if the ECU temp sensor is knackered that\'s not good either.:eek

[nikp]

Very true, but if the ECU temp sensor is knackered that\'s not good either.

Not at all!

The coolant alarm uses the temp sensor that is by the oil pressure sensor. If that\'s not plugged in, the alarm goes off. The coolant alarm is basically a metal rod that uses the water to ground itself - so if the alarm never goes off, maybe it\'s been grounded somewhere. The wire goes directly from the coolant level sensor to a plug that is located near the power steering pump. I have read that\'s it\'s meant to be a white plug, but i found mine was in fact black. Not sure if that helps really! :p

[D2BBA]

Think they must all be duff lads.  Fans never come on unless i overide them or hit AC.  The water gauge and alarm also dont work even when i lost all water!!!

Called RX but only 2nd hand FD switch

[nikp]

Have you checked the fan relays first?

[ro284]

Well it\'s good to know the fans are working, when you overide the sensor are you connecting the relays direct to a supply or supplying the fans direct to test them? i would have thought a second hand Thermo would be ok, i used a 90 deg one S/H from RX The one i took outwas 106 deg, the wire from that to relay 3 had broken so rewired it, have you got a good earth on the engine?
good luck
Bob

[D2BBA]

Have you checked the fan relays first?

Yeaj, checked relays and they all work ok, must just be ALL the sensors instead!

Chris