Looking for some help with my Focus MK2 1.6 believe it's a 2008-2009

The car was my grandfathers and I inherited when he passed it's the car I both learned to drive in and passed my test so the car has pretty significant sentimental value to me, I've been looking after it best I can regular oil changes spark plugs I replaced the filter and ATF in the gearbox etc 

Anyway before my driving test I was practicing parking and it started screaming it was getting too hot put the heater on full blast to pull heat out temp gauge came down all was well but later discovered the fan control module was bad so replaced it and the fan would come on when the AC was on or when the engine was getting warm problem fixed so I thought... 

Went on a safari with the car and we were in the big cat enclosure windows had to be up so I put the AC on was about a 26C day quite a lot of sitting still or stop start but up until this point the car hadn't shown signs it was getting too hot, anyway car screams it's getting too warm so AC off heat on full temp gauge came down pretty quick and it was fine after that no coolant lost and when we parked up and switched the engine off I could hear the fan kicking on and off for about 60 seconds. 

Now today I have tried to see if I could replicate the fault I put the overheat down to the AC just being too much for the fan and lack of airflow through the radiator, but it would seem the fan just stops once the engine passes about 95c and continues to climb with no fan running even if the AC is on or off so the car got hot coolant overflowed a bit but even then the fan didn't kick on until I switched the engine off at which point it was running at what sounded like full chat. 

I'm at a bit of a loss as to what's happening to my knowledge the fan speed is controlled by the car and it just has the one 50a fuse and the fan seems to be working but not when the engine gets too hot, is it possible it has a faulty coolant temp sensor? or anyone have a vague idea as to what might be causing it? There's no trouble codes and the car runs as far as I can tell just fine it just did a 600 mile drive without much issue besides the slight overheating in the safari.

Any help greatly appreciated I don't have the funds to chuck it in a garage I do have a forscan cable and OBD2 reader and a shed full of tools so I'm happy to try any suggestions.     

Was the fan module the same part number as the one removed?  Sounds like the fan is working for low speed, but switching off when it should switch to high speed.

There are a few different fan setups so it's difficult to know which one your car has.  Sounds like it's one fan with two speeds and an electronic module rather than a simple resistor?

I think there is only one temp sensor for both dash gauge and fan control on this engine.  You can try unplugging that with the engine running to see if the fan defaults to full speed.

I suspect this may be a wiring fault if it's not a module issue, if that's the case, it's likely to be beyond my knowledge base.

3 minutes ago, TomsFocus said:

Was the fan module the same part number as the one removed?  Sounds like the fan is working for low speed, but switching off when it should switch to high speed.

There are a few different fan setups so it's difficult to know which one your car has.  Sounds like it's one fan with two speeds and an electronic module rather than a simple resistor?

I think there is only one temp sensor for both dash gauge and fan control on this engine.  You can try unplugging that with the engine running to see if the fan defaults to full speed.

I suspect this may be a wiring fault if it's not a module issue, if that's the case, it's likely to be beyond my knowledge base.

Hello thanks for replying 

I'm not sure if the part numbers were the same I was in a rush before my driving test so just chucked it into the garage as I didn't have time to troubleshoot, it was replaced with what looked like the same part but I'd imagine they can all look pretty similar perhaps I'll pull it later. 

If it helps at all it's just the one large fan with three wires on the connector plug.

I did have to replace my BCM and code it but it was coded with the asbuilt data from the old one and I don't think the BCM controls the radiator fan. 

I did unplug the coolant temp sensor as I thought the fan would default to max speed it was spinning but just at low speed, I did also find a sort of oily residue in the coolant sensor plug so cleaned it out with some contact cleaner. 

The fan was cutting in and out and was ramping up to a high speed you could hear it and also feel a fair bit of heat being blown under the car when I let the car idle with the AC on for an extended period I was watching the temp on my phone it got up to a 100c stayed up at that temp for a while then the fan would cut in and hover around 90c 

The trouble I had earlier in the day when it was about 32c outside was that it just kept climbing it was at 120c and the fan didn't cut in once, only once I switched the car off to let it cool did the fan cut in like a madman and run for a couple of minutes.

Think I'll need another hot day to see if cleaning that coolant connector has helped at all, may just have to accept in the summer in slow moving traffic I'll have to blast the heater occasionally to keep the engine happy.   

Yeah, the fan modules all look the same so it's definitely possible that the the wrong one has been fitted now.  Unless you still have the old one, there's no way to find out the exact number of the original.

It may also be that we're overthinking this, and it's simply a worn out fan motor that only works for a short time before it gets too hot and stops working until it cools down again.

The fans aren't particularly expensive or difficult to change so it might be worth trying that.

15 minutes ago, TomsFocus said:

It may also be that we're overthinking this, and it's simply a worn out fan motor that only works for a short time before it gets too hot and stops working until it cools down again.

The fans aren't particularly expensive or difficult to change so it might be worth trying that.

Agreed, run the car until the fault, then see if there's still power getting to the fan, if there is it's the fan, if there isn't it's one of the modules that controls it

16 minutes ago, TomsFocus said:

Yeah, the fan modules all look the same so it's definitely possible that the the wrong one has been fitted now.  Unless you still have the old one, there's no way to find out the exact number of the original.

It may also be that we're overthinking this, and it's simply a worn out fan motor that only works for a short time before it gets too hot and stops working until it cools down again.

The fans aren't particularly expensive or difficult to change so it might be worth trying that.

That's a good shout I did have a thought that perhaps the fan isn't kicking on because it's tired and has had enough and the motor has become too heat soaked to kick on and because it does ramp up and down suggests the controller must be getting the right temps and inputs and at least working somewhat, I'll have a look into a new fan certainly couldn't hurt.  

4 minutes ago, DaveT70 said:

Agreed, run the car until the fault, then see if there's still power getting to the fan, if there is it's the fan, if there isn't it's one of the modules that controls it

I'll certainly give that a go and report back when I get chance to test