Driver's side radiator fan permanently ON

[nawarne]

Gents,
I went to jump in the car this evening and the O/S fan is running continuously as soon as ignition is switched on. (Mk1 Tuscan S - 04 reg')

Coolant level is good - very little needs to be added to cause a change in the swirl pot level.

I thought maybe a stuck relay? If the ecu temp sensor has gone open circuit, should both rad' fans not come on - i.e. replicating an airlock at the temp sensor?

Edited to add: temps seem normal...although if coolant level is good and fan is running, you'd expect that, I guess.

Any thoughts?
Nick

Edited by nawarne on Thursday 10th May 18:34

[VARLEYHYD]

Aircon trinary switch fault?

G

[The Surveyor]

Does your car have Air-con? I can recall this being linked to the Trinary Switch (or something like) if it's not just a dodgy relay!

Try swapping the relays over and see if the other fan starts to run.

Paul

[nawarne]

VARLEYHYD said:

Aircon trinary switch fault?

G

Good shout Graham,
I ran the aircon on Tuesday, and the fan(s) kicked in, albeit briefly, when I switched the aircon off on the controller.
Car was on the drive, I was just giving all the electrics a check. I wonder if this is the cause?
Nick

[nawarne]

The Surveyor said:

Does your car have Air-con? I can recall this being linked to the Trinary Switch (or something like) if it's not just a dodgy relay!

Try swapping the relays over and see if the other fan starts to run.

Paul

Cheers Paul for the reply.
I had a spare relay in the 'toolkit' in the boot (part of Europe touring kit).
I substituted the 'good' relay in each of the positions - with no change. The fan did stop when I pulled relay '51' (on the fuse/relay board)...so guess it does look like the trinary switch.
Nick