X300 cooling fans not running

[tuscan24]

1994 x300 3.2 Sovereign 87k

I've now had the car six months and use it 3-4 times a week, love it.

Always warms up quickly and temp sits consistently on normal. Yesterday after 30 mile run on motorway, had to sit in 30 mins of stopped traffic. Temp rose almost to red then fortunately traffic cleared and temp quickly dropped back to normal.

I've never seen either fan running and guessing they don't normally need to run,

I'm guessing faulty sensor to ecu, faulty relays, or both fans failed (it's possible to move the blades by hand)

Any advice please ?

Regards Phil

[naki]

Two things.
There's a thermal switch embedded in the rad. This gives a signal to the fan relay to start the fans.
Either one or both of these may have failed. But also check the plug is fixed on the thermal switch, and that its clean, undamaged/ free of corrosion.
Located bottom left of the rad, inside the engine bay. Back side of the rad.

The relay is big and white. It's behind the lower spoiler. Near side.

[tuscan24]

Thanks naki

I pulled the plug off the radiator sensor, its all nice and clean, no corrosion and fits tight. I was expecting to find two wires in the plug and wondered about shorting them with the ignition on to see if the fans would run. However there are three wires, one black and two whites, so i'm unsure what to try.

I haven't found the white relay yet, do I need to dismantle things to get to it.

I've done a couple of hundred miles this weekend, with no overheating problems, is it normal for the fans only to run in extreme circumstances. ?

many thanks for any help.

Phil

[tuscan24]

OK, now I'm very embarrassed !

Thought I should check the fuses, both 30amp fan fuses blown! Looked in spare fuse compartment, all present except the 30 amps! So guessing this has happened before.

Bought 2 new ones and fitted outside Halfords, drove home expecting them to be blown. Both still intact and both fans doing spurious little bursts of activity. Temperature still normal.

Any thoughts ?

regards - Phil

[BrianG]

If the X300 has the same fan circuit and wiring loom as its later X308 brother then check for broken wires running through the left hand wheel arch. I had a similar problem with blown fuses and fans not running. The relay control circuit is quite strange as it switches the fans from a series connection for slow speed operation, to parallel connection for full speed operation. This can short out the supply and blow the fuse if one of the wires (sorry, can't remember which one) is broken. It's not easy to get at the loom but a careful check may reveal the same sort of problem.

[tuscan24]

Thanks everyone for the advice, Since I fitted two new 30 amp fuses at the end of September, everything is still working correctly. Temperature gauge is nailed on 'N' after warm up, fans run just very occasionally for a few seconds after switching off.