Looking and doing a search Can I say safely that the coolant sensor is U/S? will it stop the ac condensor fan from coming on?

I know the fan tests ok, swopped the relay round, fuses good. so only the sensor

 

The coolant sensor is monitored by the ECU for a number of things, including the temp gauge. If you don't have a scanner, a parts store can read your codes and tell you the coolant sensor reading at the same time, usually free. Fan should spin freely (it is electric) and come on when coolant gets to 212F or under certain conditions stted in the RAVE shop manual.

What is happening with your truck?

 

Thats the thing there are no codes, I did say that the fan was checked using a remote battery and it works.

Something is missing between the fan and the ecu, i changed over the relay, and just about to jump the relay pins to see if the fan will work from that.

 

have you tried unplugging the cooling sensor and see if the fan shut off?

 

If you unplug relay, and short the pins in the base connector that relate to pins 30 and 87 of the relay, fan should run. The relay coil gets + battery from the main relay, and the relay coil is grounded by a green & white wire that hits pin C0636-31 of the ECU. So no junctions other than back of socket under hood and the ECU itself. Of course, if the green and white wire is skint or rubbed against ground, it would hold fan on whenever truck was started.

If coolant sensor was bad the heat gauge would show strange, and OBDII port would have wierd coolant temp data.

RAVE says -

If the engine coolant temperature gauge receives no input or the input is out of range the

temperature gauge will read cold and the high coolant temperature warning lamp will be illuminated.

Will also throw codes, but truck will run with it unplugged, assumes default temp of 185F. BTW, makes me think Rover likes the 185F temp range instead of the 200 plus range...

If relay contacts are fried, consider that the fan is starting to short out, those extra current spikes of a "locked motor" can toast the contact points.

Fan is supposed to run as follows, and you may not see it run normally if it is a cool day.

 

Thats the thing the a/c fan dos not run, the temperature gauge reads in the middle. the fan runs when i jumped the two relay pins.

Going to get a new sensor and try that.

One other thing, looking at the parts book and rave, it shows the sensor as being a square plug, Am I looking at the correct sensor as this one has a round plug and sits between the alt and ac pump on the inlet manifold?

Going to remove the alt as this is the only way to get to it?

Thanks

 

Before you do all that....

1. The sensor is working, because the gauge is working and there are no codes (like for out of range sensor).

2. The RAVE shows it as a round sensor, here is the pix from the electrical library.

3. The program logic is that IF coolant is under 212 F AND AC is not on THEN no electric fan. IF AC on AND outside temp under 82 F THEN no electric fan. It would be quite possible in cool weather for fan not to come on. (captials for logic tree, not shouting at anyone)

4. Do you have an OBDII scanner that shows the temp in digital fashion?

5. Does the same scanner show the coolant temp as ambient for a cold start, warming up to a logical value (180 - 205 F)?

6. You should be able to poke a straight pin into the green & white wire and ground it to make relay operate to make fan run. The ECU supplys a ground to make relay pull in. Wire could be broken somewhere. ECU could be bad. All sorts of evil ideas pop up.

 

BTW - what prompts you to be looking at this?

 

No sure of your Q

But I am looking into why the A/C condensor fan does not run with the AC on.

 

OK. As long as you know that it won't run that fan unless AC is on and outside temp is above 82F. So not quite that warm by the sea wall today.