Help! High speed fan won’t cut off; battery dead now!

[minty2]

Turned engine off and noticed HS fan was still running. Had to leave car for 40 mins, returned to find fan still running but not enough juice left in battery to start her. Waiting for breakdown now. Sigh....
2.5 L petrol auto so can’t push start:-(

[MarkS]

Use a torx screwdriver to unscrew the 80A fuse (FL4) in the engine fusebox.
That should stop the engine fan.

[vitesse]

Quick look at my fuse box suggests fuse 4 feeds the fan but also the auto box, so we'll forget that one. Any chance you can remove peel back the wheel arch liner and reach / separate the two large fan connectors just to get the fan to stop? (or even access them from below through the triangular finisher). I know it's not a good idea to run without a fan, depends how far you are from home.

Regards

[T-Cut]

I'd suggest you check/test/swap the relays in the control box (front bumper off, etc.)

There are lots of threads on the issue, so worth a keyword search.


TC

[minty2]

Originally Posted by vitesse

Quick look at my fuse box suggests fuse 4 feeds the fan but also the auto box, so we'll forget that one.
Regards

Actually, the autobox (and everything else it seems) runs fine without that fuse so I've put it aside and turned on the real-time temp sensing to continually monitor the coolant temp. I'll just kill the engine if I get stuck in traffic. It's not the time of year for getting things like this fixed relatively quickly unfortunately!

[minty2]

Originally Posted by T-Cut

I'd suggest you check/test/swap the relays in the control box (front bumper off, etc.)

There are lots of threads on the issue, so worth a keyword search.


TC

I'll have a trawl thanks.It must be something about the sh1t on the roads that gets to our cars at this time year. First it was an ABS fault that turned out to be a rear wheel plate problem, then the reversing sensor started to play up and now this fan business!

[minty2]

Originally Posted by minty2

Turned engine off and noticed HS fan was still running. Had to leave car for 40 mins, returned to find fan still running but not enough juice left in battery to start her. Waiting for breakdown now. Sigh....
2.5 L petrol auto so can’t push start:-(

So, I decided to order a complete replacement fan unit and await its arrival. I felt that given how awkward it will be getting to the thing just to replace a bust relay (if that's what it is), it would be more prudent to replace with OEM. Not cheap but then not second hand and hopefully will never need doing again! I'll transfer the gold resistor over. Interesting driving without any cooling fan operating and keeping a close eye on the temp via the 19/7 dash monitoring. As long as I'm moving a bit, temp hovers between 93°C and 98°C. Stationary traffic OK for around 5 mins before it begins climbing past 100°C. Managed to avoid major traffic delays so far!

[T-Cut]

Originally Posted by minty2

So, I decided to order a complete replacement fan unit and await its arrival.

That 2-speed unit should be plug'n'play to your system, however the silver resistor will fail pretty quickly and will have to be replaced. When that happens, the slow speed won't run and you're back to square one. You ought to get the uprated resistor before you fit the new fan. Check through eBay again for the gold type or check out the forum traders, electronics outlets (eg Farnell).


TC

[minty2]

Originally Posted by T-Cut

That 2-speed unit should be plug'n'play to your system, however the silver resistor will fail pretty quickly and will have to be replaced. When that happens, the slow speed won't run and you're back to square one. You ought to get the uprated resistor before you fit the new fan. Check through eBay again for the gold type or check out the forum traders, electronics outlets (eg Farnell).
TC

I have replaced the fan but have just discovered that its low speed isn't coming on, even when demanding AC. In AC mode, the high speed cuts in fairly quickly and cycles on and off unless I switch to 'econ' mode when the high speed cuts in at ~105°C and stays on until the temp's dropped to <100°C. It's been doing that since I had it fitted. I've followed Stocktake's advice and checked the gold resistor, which is OK and this is a brand new OEM motor, so what else could be wrong? The fan either wouldn't come on at all or would stay in high speed mode if it was a coolant temp sensor issue. Before I go removing the bumper again, does anyone have any suggestions about what else might be going on? Coolant level is stable.

[SD1too]

Originally Posted by minty2

I've followed Stocktake's advice and checked the gold resistor, which is OK ...

Could you just say how you've checked the resistor please David?

Originally Posted by minty2

... unless I switch to 'econ' mode when the high speed cuts in at ~105°C and stays on until the temp's dropped to <100°C.

That doesn't sound right at all. According to your earlier post you bought a genuine MGR 2 speed system complete with control box for petrol engines. We're going to have to examine the loom connectors I'm afraid. You might be able to access these without removing the front bumper.

Simon