thermal trip sensor faulty

[bigsi]

Today i managed to finally get to the bottom of the cooling fans issue.

I was able to disconnect the two connectors to the thermal trip sensor on the underside of the front cooling pipe as advised to do, i inseted a paperclip between the two and my fans fired into life!!

So it looks like i need a new sensor, upon checking i see that mine has a green ring around the top so i assume that is the one to ask for when replacing?.

I was pleased to see that one of the cooling fans i though was dead has now sprung back into life, so i will remove the fans and shroud and clean, service and replace them.

I will be starting on the cooling system next week and replacing all the pipework, and cleaning and also bathing the radiator in a cleaning tank, i will put a feed line into one of the feeds and an output on another and let it cycle clean it for a few days.

The thermostat seems to be working fine as i was able to get the heater working in the cab.

i have noticed that the fan fail light hasnt come on, i would have thought that with the thermal trip not working it would come on?

The guage for the temp is also a little wierd, as the temp climbs just above 90, if i tap the guage it drops to a normal 90 or just below, so prehaps the guage needs replaceing as does the temp sensor in the rear of the bay for the guage?

All issues aside a productive day

i now have to find out whether the manifold is cracked or if the manifold gasket is leaking.

[Splashout]

Si Glad to hear that you are getting somewhere.

As for the temp gauge could it not be that this is your thermostat opening normal operating temp is 90 deg so should go slightly above and then thermostat opens and temp drops.

[WayneB]

Simon, thats your Otter switch (not the Thermal trip unit) and the green band signifies its designed to start the fans at 92 degrees c and shut them off at 82 degrees c.

You can get a blue spot one that works at 82 degrees c and shuts off at 72 degrees c if your car is running hotter than you would like.

[USAndretti42]

i have noticed that the fan fail light hasnt come on, i would have thought that with the thermal trip not working it would come on?

The fan fail light only tells the driver that the relay isn't working. A wire goes from the output side of the thermal switch to the warning light and thence through a normally-closed relay to ground. When the fan relay is energized, it energizes relay is also energized breaking the connection so the light doesn't come on. If the fan relay fails, the wire from the light is earthed through the fan warning relay and so comes on. If the thermal switch isn't working, no power goes to the light.