Anthony489 said:

Hi

The temperature sender is a thermistor (thermal sensitive resistor) and can be connected either way round.

The connections run from door/mirror connector P060B Pins 1 and 2 to Junction D237 Pins 3 and 4, then to Junction D226 Pins 7 and 8 and finally to the Body Control Module Pins C2 and C2.

For the older vans, the wire colours were HV (Grey/Green) and HR (Grey/Red). Yours may not be the same, but will be thin (0.5 square mm cross sectional area core)

You could struggle to find "proper" connectors as these things are often custom designed for big users like Fiat and not on open sale. Your best bet is to remove the two relevant vehicle wires from the connector and butt join them to the sensor wires. Maybe a good idea to do a temporary job with a "chocolate block" connector to check it all works before doing anything more permanent.

Click to expand...

I fitted the ambient sensor a few days ago
Been keeping my eye on it .. because when fitted I noticed the temp did come on the dash but it’s at 56c
I thought maybe because handling it
Anyway I noticed it’s not dropping
Maybe a few c that’s it
It’s below freezing today and still no change on the dash
But I noticed if I remove 1 wire from wago clamps but quickly put it back in I can get different readings
Is this a set up measure trying to get it close to the temps maybe ? It’s so strange
So if quickly try to move the wire connection from the wago clamp but not completely to lose power
Let’s say the reading shows at 56c I do the wiggle of the wire the temps drops to 46c
Then do the same again with the wire it’s drops in the 30s
Then 20s
Keep doing it it’s just drops
I got it to below freezing the ice icon came in the dash followed by drive careful on Icey roads bla bla
But as I say the first connection if I just place the positive wire in the wago clamp
Same with negative in a another clamp that’s the first reading I get in the 50s every time
It drops by a few c if left alone and sticks
it seems by tripping it a little as mentioned seems to reset it down and down
Wire out completely and back it starts over again
So for blabbing on
Why is this happening
I thought it would be connect and done thanks

Hi

This behaviour is puzzling. I would expect the software to do a bit of averaging/smoothing so that readings change very gradually and don't jump around. If you disconnect and reconnect rapidly it may just average out the sensor reading with the brief open circuit reading. The normal setup is just a Negative Temperature Coefficient (NTC) thermistor, which has a resistance that goes down as the temperature goes up. At 25 degrees C it would be typically 10K (10,000 ohms). A high temperature reading would be given by a low resistance, a very low temperature reading by an open circuit.

All I can suggest is that you double check your wiring. You could also try connecting the sensor the other way round, just in case Fiat have changed to some sort of polarised sensor. I haven't used Wago clamps, presumably they have a springy blade that presses on the stripped wire core ?

If you have an ohmmeter, check the resistance of the sensor (while it's disconnected from anything else) and note the temperature.

Anthony489 said:

Hi

This behaviour is puzzling. I would expect the software to do a bit of averaging/smoothing so that readings change very gradually and don't jump around. If you disconnect and reconnect rapidly it may just average out the sensor reading with the brief open circuit reading. The normal setup is just a Negative Temperature Coefficient (NTC) thermistor, which has a resistance that goes down as the temperature goes up. At 25 degrees C it would be typically 10K (10,000 ohms). A high temperature reading would be given by a low resistance, a very low temperature reading by an open circuit.

All I can suggest is that you double check your wiring. You could also try connecting the sensor the other way round, just in case Fiat have changed to some sort of polarised sensor. I haven't used Wago clamps, presumably they have a springy blade that presses on the stripped wire core ?

If you have an ohmmeter, check the resistance of the sensor (while it's disconnected from anything else) and note the temperature.

Click to expand...

Yes it’s very strange it’s below freezing today and it’s showing 38c no change
I have tried to swap how the wires are but no change
It picks temps up that are high
Really strange