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Old 29th June 2017, 10:34   #21
frankgoldstar
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Dear Simon,

I do have a DVM, which is where the equipment becomes more comprehensive that the understanding.

As soon as I plugged the "new" fan assembly in, I ran the voltmeter round the connections in the control box and found 12v on practically everything.

This confused me, but the line in one of Arctic's postings about switching the negative side it sort of made sense.

Now you have confirmed the relays are 12v, i can at least energise the coils and see if they click.

I was going to pull the PCB's out of the housings, but bearing in mind a comment that getting them out had often destroyed them, I chickened out.

Other than powering the relays and bearing in mind the tentative diagnosis from Artic that the PCB could be U/S, is there any way to test the PCB inside the box?


Best regards, Frank
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Old 29th June 2017, 10:53   #22
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Frank,

Don't try to remove the PCB or energise the relay coils; there's a simpler way.

Place your voltmeter across the small relay's contact terminals; red probe on the slate wire and black probe on the black wire. Select a 20 v DC range.

Ask an assistant to turn on the ignition and press the windscreen demist button. If the meter shows 12 volts then the relay is not operating. If this is the case it's unlikely to be a faulty relay but you can substitute the second small relay alongside the one you're testing to prove that.

In your shoes the next thing I would check is that there is +12v on the thin yellow wire, that the thin black wire is connected to earth and that there is continuity along the thin blue/red wire from the chunky connector to the PCB spade terminal. Do you need help with this?

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Old 29th June 2017, 11:13   #23
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Dear Simon,

thanks for the testing procedure.

It is not really possible to do it just at the moment as the car is in the open and, this being Manchester, it has been grey, gloomy and raining for the past two days.

Hence me thinking about testing in some other way.

At the moment, it is frustrating to look at the car dripping water with the front off on the ground.


Best regards, Frank B
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Old 29th June 2017, 12:30   #24
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I believe I now have the correct wiring for both old (CDT) and new (CDTI) fan control in these images.

Many apologies for the earlier mistakes.


"New" CDTI fan and control wiring

https://www.facebook.com/photo.php?f...9970030&type=3

"old" CDT fan and control wiring

https://www.facebook.com/photo.php?f...9970030&type=3

Anyway, as far as I can see, the only difference between the old and new setup is the forth connector with the grey wire is on the PCB connector, whereas on the old control box the grey is crimped in with the brown blue connector on the PCB.

I seem to remember a reference to this in one of Arctic's postings, so I will try to find that and see if I understand any more than now.

Best regards, Frank B

Last edited by frankgoldstar; 29th June 2017 at 12:36..
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Old 29th June 2017, 14:10   #25
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HI Frank.
I can not see or access those links for your pictures, as I do not have FB.

Another thing I noted before you finally get sorted which you will, is that the gold resistor you have soldered into place will need to de-soldered and some heat shrink added otherwise water will get to the joint and blow the resistor.

1

You could at the same time try adding the resistor to your original fan and see if it works.

The PCB can be changed over carefully without any damage I have done this quite a few times, all you need to do is be very careful, first remove all the wiring with the spade ends using long nosed pliers.

Once these have been removed you will see that the relays are held in by tiny clips using a small screw driver tease them back and at the same time lift the relay a little, I will go out to my shed in a while and find a control box and take a few photo's of how to do it cheers Arctic.
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Old 29th June 2017, 14:21   #26
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Dear Arctic,

thanks for the information.

I am still getting to grips with how all this posting of images thing works, so I keep screwing up.

I will try again.

I did actually coat the resistor connections in silicone rather than heat shrink, but if you think this is not a good idea, I can always redo it.

It is brightening up a bit here, so if I can prise our elderly cat off my knee, I can go and have look.

Still frit about the PCB, but I can try again - gently.

Best wishes, Frank
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Old 29th June 2017, 14:30   #27
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Default Wiring iimages

I have tried to add the images of the wiring, but it does not seem to work.

I copied the link address and entered the URL in the paste image pop-up, but it still does not work.

What am I doing wrong?
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Old 29th June 2017, 14:51   #28
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Frank,

At the top of this page, in the main menu with 'User CP' on the left and 'Log out' on the right, can you click on 'Image gallery'? Is there an option labelled 'My images'?

Simon
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Old 29th June 2017, 17:50   #29
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Dear Simon,

thanks for the guiding hand on the image posting.

I have uploaded the "new" CDTI wiring arrangement.

Now it has stopped raining for a little while, I went and had a look at the car.

I hooked the wiring up to check some of the things you had posted about as copied below.

You wrote:
Don't try to remove the PCB or energise the relay coils; there's a simpler way.

Place your voltmeter across the small relay's contact terminals; red probe on the slate wire and black probe on the black wire. Select a 20 v DC range.

Ask an assistant to turn on the ignition and press the windscreen demist button. If the meter shows 12 volts then the relay is not operating. If this is the case it's unlikely to be a faulty relay but you can substitute the second small relay alongside the one you're testing to prove that.

In your shoes the next thing I would check is that there is +12v on the thin yellow wire, that the thin black wire is connected to earth and that there is continuity along the thin blue/red wire from the chunky connector to the PCB spade terminal.


I checked for continuity on the blue/brown control wire between the flag connector and the plug connector and it was fine.

I also checked that the thin black wire had continuity back to the body.

To check the yellow wire had 12v (it did) I turned on the ignition and pressed demist.

I only got as far as doing the dab with the meter and the fan started running. No idea if it was slow or fast, it scared the pants off me just starting to whizz up.

Mindful of the warnings about mini helicopters, I whipped the probe off quick.

The fan stopped ok, but I had not actually seen whether I had inadvertently shorted out something on the back of the PCB, so I stopped probing the small connectors.

I had not find 12v across the grey and black wires on the relay.

At least that seems to prove the fan will run. Why it did is a different box of frogs.

As the old control box was available, I swapped the control boxes over, although it is the wiring that is slightly different, not the boxes.

No joy there.

I will go and have another look after a quick munch.

Update. As I had taken the CDTI PCB out of the box, I carefully, I pulled the relays and put 12v across the coils. All three clicked nicely.


Best regards, Frank B

Last edited by frankgoldstar; 29th June 2017 at 18:24.. Reason: Update
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Old 29th June 2017, 20:24   #30
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Quote:
Originally Posted by frankgoldstar View Post
I only got as far as doing the dab with the meter and the fan started running. No idea if it was slow or fast, it scared the pants off me just starting to whizz up ... I whipped the probe off quick.
The fan stopped ok ... so I stopped probing the small connectors.
OK Frank, that's good. The fan started and stopped as you applied and withdrew the meter probe. That tells us that you have an intermittent open circuit on the PCB.
Quote:
As the old control box was available, I swapped the control boxes over, although it is the wiring that is slightly different, not the boxes. No joy there.
Did you preserve the different wiring when you fitted the second control box?
Quote:
I pulled the relays and put 12v across the coils. All three clicked nicely.


Simon
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