Can anyone tell me why there are 5 different terminals on the thermostat housing? I believe the main plastic connector will go to the ECU (emerald pin 33) and Battery Negative but I don't know what the other 3 would be for. They can't all be for the temp gauge.


Thermostat Wiring

The housing that's been installed doesn't seem to match the one for the kit:

http://www.kitspares.co.uk/index.php?route=product/product&path=43_28&product_id=740&car=43

Although I don't know what the two different sensor positions are on the standard one either tbf!

Id recon:

The single spade sensor will be for the temperature gauge.

The one with the junior timer (black plastic) connector the ecu temp feed.

The one with exposed terminals for the cooling fan.

quote:

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Originally posted by r1_pete
Id recon:

The single spade sensor will be for the temperature gauge.

The one with the junior timer (black plastic) connector the ecu temp feed.

The one with exposed terminals for the cooling fan.

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I'd imagine that the two 2 pin ones are the sensors - so one for the gauge and one for the ECU. I'd have thought the single pin one is for the fan relay.

Either look for ID on the housings or put a multimeter across them; when cold the sensor should read a (high) resistance, a switch should read infinite resistance (open). If you can't get a definitive reading put them in hot water and measure again - most temperature sensors will decrease in resistance gradually (negative temperature coefficient) as they heat up, the switch should go from infinite to low resistance very rapidly at a specific temperature.

Edit: The ECU can control the fans - that's the set up I have - but you can also have a thermal switch to do it.

[Edited on 3/1/17 by Badger_McLetcher]

As the first reply IMO,
The single spade will deffo be a gauge
Junior timer to ECU
Twin spades looks like a rad fan switch

The large double spade is definitely the rad fan switch you can use this if your ecu doesn't control it. If it does just leave as is or take it out and blank off hole

There's disagreement in the ranks....

Well as long as I know the junior timer is the ECU. Trial and error will have to do for the others!

Put a meter accross the spades on the double, if its an open circuit then its a switch, if it has a resistance over it then its a sensor.

But as others have said its likely to be a switch.

other way is to whip it out, put 12v across it with a bulb in line then dunk it in boiling water

As above for testing the twin one.

The single one is deffo a gauge as it works by altering the resistance on the negative side of the gauge,the path through the sender to Earth on the housing.

Hmmm apparently I'm the only one who's come across single terminal switches! I'd go with the communal experience on that one

Either way the rest of my post stands - put a multimeter across them and find the resistances.