Alfa 33 16v Radiator thermo switch question

[Spoonano]

Hello, After having my radiator out for water pump replacement my thermo fan is no longer coming on, I may have possibly connected the wires to the thermo sensor backwards and wondered if there is anyway of testing or if anyone knows the correct way to connect them.

Considering wiring a switch via a relay as it seems it turns them on at 92 degrees which is a little hot for the climate in Australia.

Thanks
Dom.

[LoneWolf33]

Hi, the sensor consists a bimetallic contacts (similar to a switch), the wiring order is not really important.

If possible check the coolant temperature with an external probe, because the coolant gauge in the
instrument cluster can't be trusted especially when the lights are on. The gauge might be fooled by voltage
drop between the instrument cluster and ground.

[BigAl33]

Test the temp from the CTS, there is a graph on what resistance = what temp

Multimeter set to 20 kOhm, should get

-10C = 9 kOhm
0C = 6 kOhm
+10C = 3.8 kOhm
+15C = 3 kOhm
+20C = 2.5 kOhm
+25C = 2.1 kOhm
+30C = 1.7 kOhm
+40C = 1.2 KOhm
+60C = 600 Ohm
+80C = 330 Ohm
+90C = 220 Ohms

[brit01]

because the coolant gauge in the
instrument cluster can't be trusted especially when the lights are on

yep this is a real pain.
I installed an extra earth from the cluster connector (but not so well done as you lonewolf which I want to get around to doing) but made very little difference.

When moving under average ambient temperatures my cluster gauge reads about 82/83 degrees but jumps up to about 86/87 when lights are turned on. alfa electricians!!!

[brit01]

Hi Dom,

I've just purchased a new radiator sender switch that turns on at 88 and off at 79.
(mine currently is 80/90) so this new one will help keep things cooler when the summer days start exceeding 35 degrees.

We'll see

[Spoonano]

Thanks for the info guys, if it can be wired either way it may be the sensor that is not working at all, could that happen from removing and refitting the radiator?

Brit, where did you source the alternative sender from? is there a part number I could possibly source in Australia? sounds like a much saner temp for it to come on rather than 92!

I was thinking about wiring in a switch with relay to turn it on and off manually, are there any thoughts on that?

Thanks
Dom.

[brit01]

http://www.ebay.co.uk/itm/1406813686...84.m1439.l2649

hi mate
this is the one I just purchased.

88/79 instead of my current 90/80.