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> PH 2 radiator fan- help, does anyone know how this works..?
dante giacosa
post 4th August 2017 21:18
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Hello-

I'm running a phase 2 1.8 T-spark (plastic engine top) with A/C.

I am trying to work out how the engine fan works, and how it has two speeds.

Conversely to the manual, and entirely inline with G Evo's post from some years ago; (identifying the relays in the box on the battery front); I understand that the radiator fan 2nd speed is the BIG relay on the left.

I also understand that I99 is the radiator fan 1st speed relay, which is in the centre-left-top socket on the G8 fusebox, above the pedals.

HOWEVER, that is where my info ends.
The schematics that we have in the MANUALS section of the forum exclude the A/C versions of the car (but do include some info if you instead look for A/C wiring).
The colour codes are 'similar' but I just need to straighten a few things out.

I do not, for instance seem to have connector G133a under the bonnet (as a big single 18 way connector) It is NOT behind the battery or behind the ECU- they are different) and I do NOT seem to have this thing L33 two-position thermal contact, which might be in the radiator.


My questions are this-

*are both relays fed directly with switched grounds from the ECU under the bonnet (as in DIRECTLY- with no intermediate connectors)? I reckon this is white/red for the 1st speed relay inside the car, and red/green, for the 2nd speed relay on the battery.

*why, when I hear the fan running under the bonnet; is it the 2nd speed position in operation? Does the 1st speed ever come in?- or does it only run with the A/C? (Incidentally; my A/C is yet to be fixed- I am either looking at the relay or the compressor itself; everything else is fine).

THANKYOU for any wisdom; in advance...

Jim

This post has been edited by dante giacosa: 4th August 2017 21:19
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Antonio
post 5th August 2017 16:01
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Hello Dante, the layout between CF1 and CF2 engines is bit different:

-First CF1 engines with M2.10.3 ECU used a thermal switch to turn on the cooling fan, and a three level pressure switch controlled the fan, regarding the aircon ( I believe the Aircon switches directly the 2nd speed).

-Usually the ECU uses 1st speed to cool down the engine and it doesn't need more. If Aircon needs the fan to cool down the condenser, the speed choosen depends from the info of the three level pressure switch. It's easy to verify the correct working of the speeds by activating them with i.e Multiecuscan
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dante giacosa
post 5th August 2017 19:00
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That is a good starting point, Antonio-

thankyou for your reply!
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shpuncik
post 6th August 2017 10:00
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what you probably need is look into "Climate Control: Manual Air Conditioner" page 36, model year '98 petrol with M1.5.5 ECU and page 53 for component locations.
http://www.alfa145.com/upload/Alfa145Manua...Conditioner.PDF

there connector G133a and switch L33 are removed - they use 4 way switch Q20 (6 pin connector) instead.

fan control either for engine cooling or A/C is done through ECU by switching ground signal to relays. ECU recieves signals from temperature and/or pressure switch and reacts accordingly. 1st speed is through resistor on fan assembly - two single wire connectors, it's very low resistance, if I remember well ~0.8 Ohm, simple multimeter should read about 1-2 Ohm. 2nd speed is direct connection.

now to your questions.

1) yes, looking into wiring diagram, both relays 1st speed I99 (top row, 2nd from left on fusebox) and 2nd speed I100 (in front of battery black base) are connected to ECU directly without any intermediate connectors. colors correct white-red and red-green.

2) 2nd speed at least on my Boxer kicks in somewhere around ~105-110C. on my JTD I've never heard it. simplest test would be to remove speed control relay and bridge terminals 30 and 87 with wire or paper circlip. do the same with second one. this way you'll see if you have both speeds.

to test A/C pressure switch Q20 you'll need to go to A/C specialist as it is tested under pressure. also I've not tried it, but my guess is if you disconect engine temperature sensor with engine running or just ignition in ON position fan should turn on instantly in 2nd speed.
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dante giacosa
post 7th August 2017 07:43
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THANKYOU Valdas!

That is IT.

I don't know how you found that- as I have spent a week going through associated schematics, without any success. That is absolutely it, except for one tiny detail- I have a light-blue / black as the switched ground into my radiator fan- although it leaves the 1st fan speed load resistor as a light-blue / white.

But it HAS to be the same cable (I've confirmed it with a continuity check, with all other associated lines disconnected) as there is a cable join in the looming according to the schematic.

I have already confirmed operation and functionality of both fan speeds by making the relevant ground connection links to the relays- they do indeed run at different speeds- the 1st is hard to hear externally with the engine running and bonnet up (I was making the connection at the cabin fusebox G8 at the time!)

Interestingly, I noticed a degree of 'control bounce' upon disconnection of each relay; after I removed the negative link; the relay would disengage, but then momentarily re-engage before coming off again. I was thinking this would be some kind of 'test' by the M1.5.5 system, as if it could see the negative presence coming back up the line at it's control output..? Who knows how clever it really is...

Anyway- I couldn't see how the standard setup tied into the A/C system, but as you say; on this schematic, the presence of the Q20 pressure switch makes it all possible.

I wish I had your brain! Thanks again...

This post has been edited by dante giacosa: 7th August 2017 07:45
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Ganz
post 9th August 2017 22:40
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Job well solved thumbup.gif


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