Thread: p38a auto cooler temp sensor??

Gents & Ladies

I wonder if someone could help me. I own a 300tdi Disco automatic that I have just recently fitted with an auto cooler out of a p38a rangie. Issue I have is that I wanted to run the temp switch off the side of the new cooler instead of the old inline switch that the Disco had.

I had to get new cooler lines made up for the new cooler, so intentionally had the old inline sensor left out. Trouble is now, it appears that the temp sensor I have seems to be short circuit all the time??

Can any of you p38a owners tell me if the sensor works like a normally closed switch (which means the sensor I have may be operational) or it works like a normally open switch (and closes when it's too hot, in which case the temp sensor I've got is cactus)?

Any help greatly appreciated

Cheers

Goldey

Originally Posted by goldey

Thks for the reply guys.

I spoke to the suppliers, they said that it is a newer model sensor that changes it's resistance as it gets hotter. The body control module then interprets the voltage on the sensor (due to the increased resistance) and triggers the over temp warning when the sensor reaches a predetermined limit. Sounds plausible, however not very helpful to me. I definitely need to know if this sensor that I have is a variable type or a fixed on/off type (like my old sensor).

This new sensor is attached to the side of the cooler tank. It looks like a solid state flat type surface mount thing that sort of confirms what the wreckers were telling me.

Cheers
Goldey

Take it out and put it in a pot of water on the stove with a multimeter attached to the terminals. (attach fly leads so meter leads dont end up in the pot!)
As the water gets hotter, an analog sensor will show an increasing resistance.
If its a std sensor it will show open circuit until it gets to its trip temperature. WHen it trips, you will see a resistance reading of only 1 or 2 ohms.