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Radiator fan issues

Milesp

Active member
Joined
6 Mar 2011
Messages
37
HI all,

Further to my previous thread about my non functioning passenger side radiator fan I replaced the fan this morning (along with AC condensors).

However, it still doesn't work!. I turned the car on with AC and the ballast resistor immediately got VERY hot (like too hot to touch hot).
Does this suggest anything else - I guess I have to admit defeat and take to a garage - electrical stuff not something I know anything about!

So frustrating!
 
The resistors do get hot so difficult to comment there ..

logically if its hot then voltage is flowing so the relay that switches it is ok ..

i would lean towards a poor earth to the fan that side ( both fans have a seperate earth ) or the resistor is faulty along with the fan you have replaced .

Resistor will only effect stage one and not stage 2 .. if the fan runs at engine temp 105 then it's not the resistor .
 

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Thanks demort for taking the time to reply. How would i check the earth of the fauty side?

Thanks, Miles
 
Make a temporary earth connection from pin 1 on the plug to the chassis of the car, it doesn`t have to be pretty, strip a piece of wire and jam it into the non-fan side of the plug and then attach it to the car body/chassis.

Sorry, I`m an engineer, so this is second nature to me, maybe not for you if you`re not a hands on type of bloke.
 
Update

Update - took car out today and when I pulled up to my gate the temp on aircon hack was >100 but both fans now working?!

Both turn on now when I switch the AC on. Not sure how to explain this...!

As an aside I drive the car in traffic quite a bit (London) and find it does get hot. What sort of temps are 'allowable' and what should I be expecting in traffic?

Miles
 
Ongoing issues

Hmm... so the new radiator fan actually does NOT work at low speed (i.e when the AC is on) but DOES work when I jump the high speed relay which means the resistor is faulty right? Is that likely on a brand new item or does it suggest that some problem elsewhere has damaged the resistor as soon as I plugged it in?

Also - what temp. should low speed fans kick in as mine (the working side) are not kicking in even at 100 deg...

Argh this problem is taking so much time to sort so frustrating!

Grateful for any thoughts
 
low speed is approx 95 with high speed about 105 C

low speed will kick in with a/c turned on or at 95 .

You would need to jump the low speed relay to test the resistor .. high speed bypasses the resistor .. you have proved the fan and wiring is ok .. it's more than likely the resistor .

if you jump the low speed relay then measure voltage at the resistor then that proves it .


http://911uk.com/viewtopic.php?t=127681&highlight=
 
Thanks deMort (again).

The side that is working when A/C is switched on suggests resistor is OK but does not turn on even when temp is 100 degrees so is not being triggered by temp only by a/c being switched on.

The side I have replaced does not run at low speed either when up to temp or when a/c is on which means the new resistor is not working. Can it just be bad luck that I bought a fan with a dud resistor...

Thanks,

Miles
 
Ok .. if both sides work with a/c on but not if a/c off and temp at 95 so it should turn on then you have a break in the wiring from the dme to step 1 relay .. or indeed a dme fault .. that's expensive .


Getting a little confused here i'm afraid ...

If you have one side that doesn't work with a/c on or up to temp then there is a problem with the feed to the resistor .. providing the resistor is new .. as per the link i posted on instructions on how to test .. you would do that .. if no voltage to the resistor then you go back to the relay ..

its needs a voltmeter on the wires going to the resistor .. a/c on and you should have voltage .. if no voltage then backtrack to the relay .. if voltage then its the resistor ... off hand im not sure of the colour of the resistor wire but there is only 2 wires .. test each for a voltage with a/c on / off .. if no voltage then its back to the relay ..

relay ..

85 / 86 12 volts one side and earth the next.
87/30 .. 12 volts one side and the output switched voltage to the item in question .. in other words you won't measure anything( relay out ) as its the output for the 12 volts to the item .. relay in and switched on and you get 12 volts .
 
zz8c7rU.jpg
 

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