Thermosensors

jschrauwen · Post by **jschrauwen** » May 2nd, 2005, 8:10 pm

Are the 2 (green and black) thermosensors located by the coolant filler neck interchangable. My green one is broken and I was able to find a black one that looks identical but not sure if it has a different rating.

PATDIESEL · Post by **PATDIESEL** » May 3rd, 2005, 12:57 am

the parts manual lists them as the same part number.

jschrauwen · Post by **jschrauwen** » May 4th, 2005, 4:58 pm

PATDIESEL wrote:the parts manual lists them as the same part number.

OK, that's strange, when I called Mazda just to get a price, they specifically asked if it was the black or green one. A quick continuity check on both shows me that they both have different resistance values. So I don't know what's the scoop. Same part number for 2 different coloured sensors with 2 different resistance values. Then again one of my sensors could be toast and be giving me erroneous readings. Any one have insight on this - Mazda like usual doesn't get into any depth with stuff like this. There solution to most problems is replace it. Nice if one could afford it all of the time and at $50.00 cdn a pop that's pretty pricey..

jschrauwen · Post by **jschrauwen** » May 6th, 2005, 7:46 am

lakersfan1 · Post by **lakersfan1** » May 6th, 2005, 10:32 am

Stands to reason it's different resistance if one is broken.

babyblueMX3 · Post by **babyblueMX3** » May 6th, 2005, 11:06 am

I think I have one laying around the garage if you want it..lemme check and get back to you..

georgechicken · Post by **georgechicken** » May 7th, 2005, 4:35 am

One thermosensor was used on the 92 and 93 models only (maybe 94 also...) as a dedicated sensor for the fan... It would provide input to the ECU which would in turn power the radiator fan to a higher or lower power level in response to the coolant temp. the other sensor was for ECU data and gauge display purposes. Sorry, cant tell you which one was green and which was black off of the top of my head, but im almost positive that the fan thermosensor was the one right by the filler cap on the timing belt side of the motor. Good luck!

Daniel

kiwi_MX3 · Post by **kiwi_MX3** » May 7th, 2005, 5:54 am

Can you post the restance values John and ill measure mine up
on the K8 and KLZE..

lakersfan1 · Post by **lakersfan1** » May 7th, 2005, 10:41 am

georgechicken wrote:One thermosensor was used on the 92 and 93 models only (maybe 94 also...) as a dedicated sensor for the fan... It would provide input to the ECU which would in turn power the radiator fan to a higher or lower power level in response to the coolant temp. the other sensor was for ECU data and gauge display purposes. Sorry, cant tell you which one was green and which was black off of the top of my head, but im almost positive that the fan thermosensor was the one right by the filler cap on the timing belt side of the motor. Good luck!

Daniel

Neither of the ones you're discussing are black. The black one is for the temp gauge in your gauge cluster.

Then 92 and 93 have a green one (clearly visible) for the fans. Then all years have another green one towards the top of the neck for the ECU to determine timing based on the water temp. Then the 94+ just use the same signal input from that one sensor for the fan turn on also.

georgechicken · Post by **georgechicken** » May 7th, 2005, 8:29 pm

cool... a bit of info i believe I was unaware of... thanks!

Daniel

lucky13 · Post by **lucky13** » May 7th, 2005, 10:20 pm

hay jschrauwen do you have a code, for your thermosensor to be borken. I think mine is borken and I have a code on.

jschrauwen · Post by **jschrauwen** » May 7th, 2005, 10:46 pm

lucky13 wrote:hay jschrauwen do you have a code, for your thermosensor to be borken. I think mine is borken and I have a code on.

Sorry no code. Haven't tried pulling codes yet with the KL31 ECU. It only got broke when I was trying to remove it to clean it - excessive engine heat made it quite brittle - I believe.

LF1 - I retained the filler neck portion from the K8 as part of the obligatory carry-over with a ZE swap. The wiring harness plastic connectors for the thermosensors that are located on that filler neck portion are also correspondingly colour coded for the 2 thermosensors (green and black). They are both identical in size and shape and both are 2 wire units. The green one is positioned approx at the 2 o-clock from the filler cap. The black one is postioned at the 5 o-clock. Bothe 2 wire connectors feed into the larger wiring loom that runs along/beside the cam belt cover to the rear of the engine.
So you say the green one is utilized to turn the fan on. Is that the drivers side fan because that one triggers on and off as the engine temp rises and falls while driving in the city? The reason I ask is that I can't recall the last time the fan on the passenger side ever came on. How is that one triggered or when should that one come on?

Kiwi (Matt) - I don't have the readings any more unfortunately - threw the piece of paper out - sorry.

I have secured a second hand green one from the scrapyard but I'm not sure as to it's integrity. Had to use a heat condusive locktight to repair a possible crack between the plastic and metal. Hate to spend $50.00 on a Mazda replacement.

lucky13 · Post by **lucky13** » May 7th, 2005, 11:26 pm

Well I have a code and it's 69. I think thats the thermosensor. The thing is today I saw both fans on. The connector for the passanger fans is just wires connected to the fan's connection. So I don't know how to take that dame code off.