56 replies to this topic

[UCgazman]

Thought I would start a new thread to hopefully grab the attention of a few A9X owners. Continuing on from this thread - http://www.gmh-toran...wiring-diagram/ I'm looking for a little more info on the factory fitted electric fan; things like wire colours, how/where the fan motor is earthed, a couple of good pics of the relay pinouts...

 

Its a pretty basic setup but I just want to make sure I have the right information before I draw the schematic.

[Shiney005]

I don't have much, but it may help a bit. (Anything for you after the work you put into the other diagrams)

 

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The blue car is brand new.

 

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[Shiney005]

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[Shiney005]

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[Dr Terry]

Do I see 2 green wires at the relay base.

 

As far as I can make out we have a thick red for the +ve supply wire from the alternator, a thin green wire to the temp switch on the radiator tank & what looks like a tan or pink wire to the fan itself.

 

If there are 2 green wires at the relay base, that would indicate that the +ve wire to drive the relay, which comes from the idle stop solenoid is also green.

 

Are there only 4 wires at the relay base ?

 

Dr Terry

[Shiney005]

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[Shiney005]

 & what looks like a tan or pink wire to the fan itself.

 

 

 

Dr Terry

Looking at the black car and the blue car, I would say that tan wire was once red, or has been replaced at some stage. It was a poor example to post up.

[hanra]

Is it a standalone CCT?

 

So the key could be out of the car but if that temp sensor in the radiator is still hot enough to supply a GND, the fan will continue to run as the relay supply comes straight from the battery? 

Shame you dont have Sheet 12H-32. 

Edited by hanra, 07 June 2022 - 02:54 PM.

[Dr Terry]

Is it a standalone CCT?

 

So the key could be out of the car but if that temp sensor in the radiator is still hot enough to supply a GND, the fan will continue to run as the relay supply comes straight from the battery? 

No, because the positive relay coil supply comes from the idle stop solenoid, which is ignition switched.

 

Ignition off = no fan operation.

 

Dr Terry

[hanra]

Ok. Where is that situated on the engine. Carby? Where and how does the wiring route from the engine to the radiator support panel?

[Dr Terry]

Ok. Where is that situated on the engine. Carby? Where and how does the wiring route from the engine to the radiator support panel?

As far as I can make out, the wire connects to the idle stop solenoid at the carby (green wire near the air cleaner in post #4) it then runs thru black plastic sleeving which is nylon tied to the earth cable & then around the battery. I believe that it connects to the pink (ign +ve) wire just under the heater hose near the water pump in the same pic.

 

Dr Terry

[UCgazman]

Awesome pics Laurie, that helps a lot!

Are we going with red for the fan +12v? I think I have all the other info I need to start drawing this up.

[Shiney005]

It is a pity the parts books drawings weren't in colour.  Looking at the black car above, I would say it hadn't been messed with because it still has the original retaining clips. If an auto electrician had replaced the fan at any stage it would have cable ties instead.  I would say red and black for sure.

This drawing shows what Dr Terry was explaining above.

 

 A9X Fan wiring harness 2.jpg   136.33K   9 downloads

[Dr Terry]

Awesome pics Laurie, that helps a lot!
Are we going with red for the fan +12v? I think I have all the other info I need to start drawing this up.

I reckon so too. Looks like:-

Thick red wire from alternator to relay (with inline fuseholder ?)
Thick red wire from relay to fan connector
Thick red wire from fan connector to fan motor
Thick black wire for fan motor earth to body bolt
Thin green wire from pink at carby/engine harness piggy back connector to relay
Thin green wire from relay to thermo switch at radiator top tank

How does that sound Garth ?

Dr Terry

[UCgazman]

Yeah that's what I was thinking. Is there a fuse holder? - maybe just above the alternator in that last pic?

[Dr Terry]

Yeah that's what I was thinking. Is there a fuse holder? - maybe just above the alternator in that last pic?

Yes, there is a fuseholder, just above the alternator in that pic.

 

Let's face it if you're running a heavy draw item like a radiator fan directly from the alternator it has to be fused.

 

Dr Terry

[UCgazman]

What size do you think - 25-30A?

[Shiney005]

In HX Statesman it was 25 amp.

 

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[Bruiser]

Is there a watt rating stamped on your fan motor?
You probably already know watts = volts x amps
Or p = vi in technobabble

[Dr Terry]

In HX Statesman it was 25 amp.

 

BD1203.jpg

That fuse is for the blower fan inside the heater/a-cond housing under the dash.

 

For HQ-WB factory a-cond the auxiliary fan (in front of the condenser) was protected by a circuit breaker.

 

Having said that I think a 30A fuse would be adequate for the A9X fan. 

 

Dr Terry

[Rockoz]

Fuses arent meant as protection for the equipment on the circuit.

They are solely for protecting the wire that actually supplies it.

 

P=EI

E=IR

 

Cheers

 

Rob

[Dr Terry]

Fuses arent meant as protection for the equipment on the circuit.

They are solely for protecting the wire that actually supplies it.

 

P=EI

E=IR

 

Cheers

 

Rob

I was taught that a fuse (or circuit breaker) was to protect the entire circuit including the wiring & the device itself.

 

In this case if the red wire to the relay or from the relay to the fan, was shorted to earth the fuse would blow to prevent a fire. Likewise, if the fan motor ingested some water & became seized, this would cause a considerable increase in current & again possible fire, so the fuse would blow to prevent it.

 

Dr Terry

[Rockoz]

You may have been taught that, but it is fundamentally wrong.

If the fan for instance becomes a problem, and it draws excessive power, the fuse blows to protect the wiring.

The result is that the wiring should still be okay to connect a new fan.

The fan is stuffed and requires repair or replacement anyway.

The bit on the end is generally accessible for repair or replacement, whereas the wiring is usually considered fixed and not so easily replaceable.

 

This principle is why there are different recommended fuse sizes for different sized wires.

 

And it is a principle in all areas of electrical and electronic design.

 

Cheers

 

Rob

[Dr Terry]

I think that we should agree to agree here. What you say is 100% correct, but the fuse can prevent fire damage to the wiring or the within the device itself.

 

When a fuse blows it can always prevent ongoing damage to any switchgear, relays or even power transistor in that circuit.

 

But I will agree with your basic premise that the main saving in an automotive situation is to the harness itself.

 

Dr Terry

[Rockoz]

Basic Electrical Principle in design.

Simplistically put, fuses and circuit breakers for overload and short circuit protection are to protect nothing but the wiring.

 

Some earth leakage devices are to protect humans/animals.

Many are solely for wiring protection only.

 

 

Cheers

 

Rob