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Old 28th September 2021, 08:09   #1
Pistons_and_processors
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Default Wipers and fan query

Hi all,

New to the forum and first post.
Want to thank everyone who posts as I’ve already found a wealth of information on here as I’ve being doing jobs to the car.
I have a couple of queries I could do with assistance on. I’ve had a look and found similar issues but no definitive answers.
1. Rain sensing wipers. Mine currently don’t work correctly at the first setting that should be the intermittent rain sensing. I just have ‘on’ permanent wiping. I’ve switched the relays round and checked fuses but no change. Additionally the prism (on the glass) doesn’t appear to have any damage or deformities.
Any suggestions before I take off the sensor body and swap it over?
2. Engine fan and AC. My engine fan comes on (really high speed) regardless of outside temperature when I put on the AC. If the AC isn’t on the Fan kicks in around 100Degrees to cool the engine normally.
Having had a ZT a few years ago in don’t remember that happening. Any ideas or now just a querk of a ageing car?!

Thanks
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Old 28th September 2021, 11:20   #2
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Swap the ecu on the rain sensors (the black unit that’s clipped to the screen)

The Dan sounds like your low speed has failed, can you see a silver resistor behind the grille on the plastic fan housing?
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Old 28th September 2021, 11:27   #3
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Quote:
Originally Posted by Pistons_and_processors View Post
2. Engine fan and AC. My engine fan comes on (really high speed) regardless of outside temperature when I put on the AC. If the AC isn’t on the Fan kicks in around 100Degrees to cool the engine normally.
Hi Gavin and to the club.

If the fan's triggering at 100˚ then the fault must be elsewhere. The symptoms you describe suggest excessive air conditioning refrigerant pressure. This may be caused by loss of fins on the condenser or previous incorrect charging. Book a home visit from a local self-employed mobile air con. specialist. Do not go to Fast-Fit outfits or general garages offering air con. service.

Simon
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Old 28th September 2021, 16:32   #4
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- - - the Fan kicks in around 100 Degrees to cool the engine normally.
Hello Gavin, how frequently does this happen? A diesel rarely hits 100C under 'normal' circumstances. Coolant inventory OK?
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Old 28th September 2021, 17:00   #5
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Thanks for the reply’s.

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Originally Posted by T-Cut View Post
Hello Gavin, how frequently does this happen? A diesel rarely hits 100C under 'normal' circumstances. Coolant inventory OK?
TC
Oh this has only happened whilst the car was static having a carbon clean, still took over a hour before it happened! More interested in it concurrently running when the AC is on.

“ The Dan sounds like your low speed has failed, can you see a silver resistor behind the grille on the plastic fan housing?”
I’ve had a look through the front upper and lower grills and couldn’t see a silver resistor. Where should it be located?

I’ve a wiper ECU to swap over so will give that a try.
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Old 30th September 2021, 10:49   #6
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Hi guys.

Quick update a change of the ECU sensor box has resolved the wiper issue.
Now just leaves me the fan, which I suspect will be worn brushes.
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Old 1st October 2021, 06:35   #7
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Now just leaves me the fan, which I suspect will be worn brushes.
Hi Gavin,

You've reported that your fan works on both slow speed and probably medium speed here:
Quote:
Originally Posted by Pistons_and_processors View Post
My engine fan comes on (really high speed) ... when I put on the AC. If the AC isn’t on the Fan kicks in around 100 Degrees ...
Can you therefore explain to me how you can have worn brushes?

You also might like to reconsider my post no. 3.

Best wishes,

Simon
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Old 1st October 2021, 08:35   #8
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Thanks for the reply.
My reasoning is I only have one fan speed, ‘going like the clappers’. That’s either when the air con is activated or when the engine hits 110 degrees.
Other threads suggest it should be on a low fan speed initially when the AC is on and also stepped fan sequence from 100 degrees engine temperature.
I’ll look to book it in to get the air con ruled out.
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Old 1st October 2021, 08:53   #9
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Quote:
Originally Posted by Pistons_and_processors View Post
Thanks for the reply.
Quote:
My reasoning is I only have one fan speed, ‘going like the clappers’. That’s either when the air con is activated or when the engine hits 110 degrees.
Other threads suggest it should be on a low fan speed initially when the AC is on and also stepped fan sequence from 100 degrees engine temperature.
I’ll look to book it in to get the air con ruled out.
Hi Gavin.
Look the front grill at about 14.00Pm for the silver resistor or the two lugs which it should be connected to.
1

2

Also to double check it's you low speed that is running on your diesel car, which on a four wire three speed fan is quite fast.

Do the demist test, engine off turn key to II on the ignition, make sure that all the A/C is off, then press the demist button.

Once pressed check through the front grill if the fan is running continually.
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Old 1st October 2021, 10:39   #10
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Quote:
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Hi Gavin.
Look the front grill at about 14.00Pm for the silver resistor or the two lugs which it should be connected to.
1

2

Also to double check it's you low speed that is running on your diesel car, which on a four wire three speed fan is quite fast.

Do the demist test, engine off turn key to II on the ignition, make sure that all the A/C is off, then press the demist button.

Once pressed check through the front grill if the fan is running continually.
Hi Arctic,

On closer inspection I have the silver resistor. (Would post a picture but not sure how to yet).
Done the demist test, the fan does not come on. I can hear a hum from the fan location. Does that suggest the resistor needs replacing?

Thanks to the forum for all your help so far!
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