Water Temp Gauge Problem - Gary

[David Nock (RIP)]

First up some Pics so we see what\'s going on.

[David Nock (RIP)]

On the wiring diagram I\'m using (Haynes Best), you can see the water temp and fuel gauge both share the same voltage regulator. I don\'t for one moment think that the regulator is faulty but we said we would explore it.

The back-of-dash pics show that 3 leads disappear over the edge of the cluster (Screwdriver pointer) and they go inside the unit. I think they\'re the connections to the V Regulator and I also think it\'s an electronic gubbins inside the cluster. (It came as a surprise to find that other things like diodes etc are not on the back but are inside).
I also saw some screws up above the instrument cluster....that means the whole dash might not have to come out to get the instrument cluster out from the front??

So back to the circuit, the wiring to the temp sender unit comes off one of those two big circular plug assemblies that you can see in the middle of the cluster (Like an old style radio valve base - these are X-05 and X-06).

From there the wiring goes straight to the connector X-01 which is lying on the nearside inner wing. On the S3/12A it\'s a yellow wire with brown bands which goes from X-01 straight to a bullet connector on the end of the water temp sender.....that\'s it. We know that colour code for certain from Ian\'s S3 problem, but the Haynes colour codes do seem incorrect in places.

Just a thought Gary. Is the sender an angled upwards thing on the 13B, next to the oil pressure switch? I wonder if they\'re a different resistance to the 12A because of the electronics on the later engine? Worth checking out?

I still think that from connector X-01 back to the dash, it\'s solid stuff that doesn\'t often go faulty. So I would check and recheck the sender end of the wiring.

Hope that helps.....Dave.

[gnj37]

Sorry was sleeping for a few days  bought a rally car  that\'s  sorted  i will now get back to Mazda things

[David Nock (RIP)]

Bit more on this, I stumbled across the Water Temp Sensor resistance check in Haynes yesterday.....This is for an S1, doubt it will be much different for S2 or S3;.... 13B could be different though.

Take the bullet connector off (Sensor on the left of the Engine near to the Oil Filler).
Connect an ohmmeter between sensor top and block.....Between 105 and 233 ohms is the cold reading......20 to 50 ohms is the reading with the engine warmed up.

So it seems to reduce resistance from around 200 down to 20 ohms as it goes from freezing cold to full hot.

Also on nearby pages it confirms that the whole dash does not have to come out to get the instrument cluster out if you need to.

[A7RXY]

A bit of light bedtime reading then David ....................

[David Nock (RIP)]

Funny that you should say that Dibs. We went for a trip out in Gus yesterday. (The roads were dry and clear for the first time in a month).

The trip fired me up to think \'come the better weather I\'m going to get that faulty fuel sensor out\'. So I thumbed through Haynes last night and then .....I carried on with the Mazda S1 workshop manual in bed!

Best of all Haynes suggests that the sensor will just come out sideways without dropping the tank. Since that ring of blxxdy awful flange screws were last out only a couple of years back when I changed the tank, I figure I can do it fairly easily.

[A7RXY]

I look forward to hearing how easy it is in reality, call me a pessimist but tried to remove the horizontal panel behind the rad, and only two of the bolts would undo the rest just snaped, so out came the reverse taps, and yes that snaped, time for a cuppa me thinks...............

[CHC (RIP)]

Snap Dibs - when I did JAZ the same thing happened to me (but only one).  I ended up drilling out and retapping .... what a sod!

[CHC (RIP)]

Bit more on this, I stumbled across the Water Temp Sensor resistance check in Haynes yesterday.....This is for an S1, doubt it will be much different for S2 or S3;.... 13B could be different though.
 
Take the bullet connector off (Sensor on the left of the Engine near to the Oil Filler).
Connect an ohmmeter between sensor top and block.....Between 105 and 233 ohms is the cold reading......20 to 50 ohms is the reading with the engine warmed up.
 
So it seems to reduce resistance from around 200 down to 20 ohms as it goes from freezing cold to full hot.
 
Also on nearby pages it confirms that the whole dash does not have to come out to get the instrument cluster out if you need to.

Yeh, now I think back to JAZ, the \'clock\' probably should come out without removing the complete dash. Either way, the main difficultly is limited access alround and especially to extract the speedo cable, having conquered that element, the clock assembly then pushes forward and you just uncouple the two large \'disc\' connectors (one black, one white). I just can\'t remember whether this next bit is actually necessary but by dropping the steering column from the dashboard supporting frame (two studs), it may give sufficient access to withdraw the clock assembly without removing the steering wheel & shround.

[gnj37]

Taking fuel tank out was easy i am kicking myself that i didn\'t check fuel sensor then mind i saw the state of the screws and thought i will leave well alone but the tank its self is fairly easy just you need a bit of help when putting back in with fuel neck