[Phill 34]

Hi Guys, my roadster has been off the road for a couple of years and I have started to fix her up. However the Radiator fan is constantly running once the battery is connected. Obviously this drains the battery,
The coolant temp sensor seems ok as the resistance changes with temperature and was replaced not long before being parked up.
When running turning the AC on Increases the fan speed. Apart from putting a manual sw into the circuit I'm not sure where to look next.

Any ideas guys?

 

[vadsoom]

I’ll need to look at the schematics to me sure, but I can think of a few things that can cause this-

The temperature sending unit is flaky and telling the SAM that the coolant temperature is hotter than it is in reality.

There is a wiring or grounding problem that’s resulting in wonky readings.

Coolant levels are low and there is an air pocket that’s causing strange temperature readings.

The cooling fan relay is sticking.

 

[Phill 34]

Thanks Vadsoon, I've ordered a new coolant sensor on the off chance the resistance is off.
Do you know which relay controls it, if it inside the SAM the part number would be useful or can it be swapped with another for testing?
Before re wiring
Many thanks

 

[vadsoom]

Phil,

I’m not home today, but will have a look at the schematic when I get home.

 

[Phill 34]

Hi Vadsoom
Did you have chance to look? I e changed the coolant sensor but no difference. Just can't seam to narrow it down further TIA.

 

[vadsoom]

Phil,

You are working on a 451 ICE, correct?

If yes, the relay is built into the SAM. There isn’t much that controls the operation of the fan, so I think probably the relay contacts are stuck shut. What do you think?

 

[Phill 34]

Thanks for the photo of the circuit diagram. Next step will be to take the SAM apart and check the connections
The SAM label is attached
Thanks again for the help

 

[vadsoom]

In my experience, wires seldom go bad unless they are being flexed or exposed to water or other chemicals. If the fan is running, the wires to the fan are ok (complete circuit). It might be worth checking the ME-SFI module to see if it got wet before digging into the SAM.

 

[jwight]

He's got the 452 roadster in the UK. Evilution should be able to help.

 

[Phill 34]

Thanks Vadsoon. I'll check that out too.

 

[vadsoom]

Thanks, Jwight. I missed that

 

[forumoto]

How did you resolve this problem buddy, I have same issue with 451, the fan does not turn on, when I command it with scan tool from the SaM it won’t turn on, sometimes I disconnect the batter negative and put it back, it come on direct without me turning the key to ON. I got the sam replaced because of this, the old sam, it wasn’t coming on at all, but when I got used sam install. I remembered I was able to command the fan and it came on, both from Sam and Pcm/Ecm module , I leave the car for 3 weeks and the battery went dead, I jumped started it and this direct thing started with the fan, but it doesn’t not switch on everytime I connect the battery terminal, I need to remove the terminal couple of tile before I will get it to work direct on, no fault codes on the SaM with this issue or Pcm. Assist please