Rad fan, still not working, diagnostic approach?

[Geoff Brown]

If all the peripheral components are working then the ECU must be suspect? As it switches on the fan from signals received. It is not beyond any bounds that the ECU software has been corrupted in the cooling fan department?

Lets put it this way if I can receive an R400D with the incorrect software loaded in the ECU any one can.

[CtrMint]

Sorted. gave it 5mins running, pulled the sensor plug and the fan kicked in, looks like it was that fuse box connection all along!  

Not great from CC there! 

[rj]

The looms are made by a sub-contractor, so apart from pushing the price CC are not to blame for this.

[CtrMint]

Hmm, still think a QA check should have spotted this and I suspect CC do the loom install into the car.  At the end of the day whoever installed the fuse block into the car should have spotted it.  As soon as I unbolted the box it was clear the connector wasn't seated.

[MADMALC]

'The looms are made by a sub-contractor, so apart from pushing the price CC are not to blame for this'

CC do not make anything, which is handy, as it would appear that it absolves them from blame for any issues that appear in their products.  

Nothing appears to have changed at CC over the years, QC is still not what it should be.

Very pleased that you have solved your issue, it is fortunately or may be unfortunately part of the CC experience.

 

[rj]

You had had the relay removed, right? Woul this have pushed the terminal further out?

Not sure it would have been that easy to spot before and given the number of wires I doubt I'd have spottet it myself

[CtrMint]

I thought that, but given the fault existed before I started messing with the relay, and the terminal fixed it i dont think so.
Also I pulled on it multiple times once I'd corrected it and checked with inserting and removing the relay, it stayed put.  I think its clear what the problem is.

 

[rj]

I had a pin falling out on my 2006 Passat headlight. It just happens.

That pin fell out when I had the headlight off for changing the A/C condenser and the car could hardly start as it was one of the can bus wires.

I don't know if the looms are supplied to CC with or without relays. If the first it would hardly be possible to spot.

I

[aerobod - near CYYC]

Good that you found the problem connection. Did the spade connector lock into the block when you pushed it in? It may have been inserted into the slot the wrong way round, so the plastic locking tab may not be holding the spade correctly.

[ScottR400D]

Glad you got it sorted. Another black mark for CC. 

Its alright trying to deflect ‘blame’ from them but they can’t avoid the responsibility. It’s CC who make all the money from these cars and any business with any kind of commitment would have systems in place to, at least, fulfill basic system checks during basic assembly. 

Its fairly clear that CC aren’t like that.  

 

[CharlesElliott]

Glad you sorted it. Yes, it is a PITA and very annoying at the time, but it is all part of building a car and makes you feel even more positive when it is finished!

[ECR]

I've followed your build and the problems you have encountered. You have had quite a few occasions where you were close to throwing the towel in. It's a fact however that overcoming these obstacles (with the help of many Blatchat contributors) has made the car more "yours". I suppose it must be like the pain of childbirth bonding mother to child...

You have also made many new acquaintances during the problem solving and will feel good in their company when you finally meet them at a Club event.

Pain equals gain, and you are surely very close now to that glorious (and nail biting) first drive.

[CtrMint]

ECR I hear what you say completely, I've learnt more than I thought I would and not all mechanical.  I'm sure if it wasn't for the limited physical access I probably would have thrown the towel in already.   What I need now is a smooth test, registration and summer with the car where I can start to appreciate it.  A chance for it to win me back over if you will.  

I went to see a local specialist today, South Coast Performance, the owner is going to set the car up for me and put it through the Manx test.  Assuming I get a few final bits finished this weekend, the car should be going down to SPC on Wednesday.  Then immediately back to Oakmere for the PBC, and official check, plus service book stamp.

I do hope someday to get the car across the UK for a club event, hopefully, put some names to faces. 

 

[rj]

I am also sure that if it was not for your location, a lot of club members would have stepped in and helped you onsite.

 

[Mark w]

All these build issues are complete hassle but the upside is that Caterham owners who go through this learn a lot about their cars and , personally , i find this experience worthwhile.

Tracing an electrical fault on my 620R increased my knowledge of Lambdas, coil packs ,Coil wiring looms ,  ECU settings and the like . At the time it was a complete pain in the Ar$e !  

[CtrMint]

Hmm, 
I thought I'd solved this, and sure the electrics now seem fine, unfortunately, I still can't get the fan to switch on automatically. It only switches on when I disconnect the sensor. 

Derek @CC tells me the fan should kick in at 102C, I'm going to 108C still no joy, it's pretty clear on the dial.  I'm sure the thermostat isn't consistent too based on the temperature of the bottom hose. 102C as a trigger point seems contradictory to many comments and discussions in blogs and forum posts????

Even if the thermostat was dodgy the lack of cooling via the radiator would still cause the temperature to rise so that the fan kicked in.  I'm not sure what to do. 

I've tried lots to sort this, including having the car jacked up at the front too to ensure the highest point of the car is at the front. 

[rj]

Which sensor is it you disconnect?

And how do you read the actual temperature?

[CtrMint]

The connector on the sensor which is plugged into the block near the u bend above the submarine on the hot side of the Duratec.

On the dash and with an OBDII tool, they are both reading the same.

[rj]

What does the OBD tool read when you remove the connector from the sensor?

 

[CtrMint]

Didn't actually check that scenario 

[aerobod - near CYYC]

Unless it has changed for your 420R, Pin 33 on the MBE ECU should be controlling the cooling fan relay (my car has that wire as black/purple). On my R400 the relay is on the MFU board, as opposed to on the fuse block.

if you can find anyone on the IOM who has an MBE ECU cable, you could put Easimap (https://www.sbdmotorsport.co.uk/index.php/products/index/4327) on a laptop and watch the fan signal from the ECU change as it hits the set temperature. If you have the 9A4 or 992 ECU this cable is what you need: https://www.sbdmotorsport.co.uk/index.php/products/index/2663

[rj]

James,

It is an 9A4

CtrMint,

When it kicks in when the sensor connector is removed, then the output is OK. It would be very nice to see what temperature it reads when the fan kicks in. You cold replace the sensor with a 50ohm resistor in series with a 1k potentiometer.

If it's the standard mini timer connector you have for the senor I could even make the circuity up and send it to you but to get any sense from it you need to have access to the OBD.