Fan doesn't work on 4, works fine on 1-3

[ProggerPete]

Hi all,
I'm trying to diagnose a fault with the fan in a VN commodore. Looking around on the forum got me looking at the resistor array under the leaf guard. This has obviously been replaced at some point as it's not the same one that is shown in any pictures I've seen. I tested across the contacts and there are no open-circuits or short circuits so I think the array itself is probably ok. This fan used to work fine all speeds, then speed 4 became intermittent, now speed 4 is a no go.

This makes me think it's probably the switch itself. What do you think of this diagnosis? If I'm right can the switch be repaired or does it need to be replaced? If it needs to be replaced can you get just the fan speed switch or do u need to replace the whole fan unit?

[stockvp]

ill have a look in the manual 4 ya

[pro_gmh]

My fan switch doesnt work from 1-2 but does 3-4 wtf is goin on here? the switch isnt vac operated ay?

[ProggerPete]

Adox, have you checked the resistor array? Everyone I saw with that problem fixed it by replacing the array.

[silver_bullet]

mine wouldnt work on 2 and 3 so i replaced the resister and all systems were a go, even if u check for shorts and stuff the easiest thing to do is simply replace it, symply unplug the old and plug on the new, u can get them from spare depots at ur local holden joint. very rarely switches die. hope this helps.

[ProggerPete]

mine wouldnt work on 2 and 3 so i replaced the resister and all systems were a go, even if u check for shorts and stuff the easiest thing to do is simply replace it, symply unplug the old and plug on the new, u can get them from spare depots at ur local holden joint. very rarely switches die. hope this helps.

I suspect no.4 bypasses the resistor array. I could be wrong though. What makes me wonder is that I can't find a soul who has had no. 4 go and still had any other fan speeds.

[samuels]

Hi all,
I'm trying to diagnose a fault with the fan in a VN commodore. Looking around on the forum got me looking at the resistor array under the leaf guard. This has obviously been replaced at some point as it's not the same one that is shown in any pictures I've seen. I tested across the contacts and there are no open-circuits or short circuits so I think the array itself is probably ok. This fan used to work fine all speeds, then speed 4 became intermittent, now speed 4 is a no go.

This makes me think it's probably the switch itself. What do you think of this diagnosis? If I'm right can the switch be repaired or does it need to be replaced? If it needs to be replaced can you get just the fan speed switch or do u need to replace the whole fan unit?

id try replacing the resistor first,as if your careful with it,and GMH have it in stock(sometimes their terms and conditions say that electrical components are not returnable)you MAY be able to return it if it's not the resistor,then i'd be looking at a faulty switch.

[pro_gmh]

Whats the resistor array?

[ProggerPete]

Adox: It's a component under a dome under the leaf guard under the windscreen wipers. If it's busted your fan speeds stop working.

[pro_gmh]

Yep, but i have 3 and 4 fan speeds working, could it still be busted?

[ProggerPete]

any fan speeds between 1-3 busted and 4 works = resistor array

[samuels]

any fan speeds between 1-3 busted and 4 works = resistor array

just a question why would # 4 work when resistor is buggered and stops 1-3? they are all on the same circuit,i'm no auto electrician,just know the basics from my apprenticeship days many,many moons ago....also my manual says no fan speeds on switch 1-4- faulty resistor,or switch.

[ProggerPete]

My understanding is this...

Fan speeds 1-3 go through the resistor array to drop the voltage to the fan thus dropping the fan speed. Speed 4 bypasses the resistor array and applies full voltage to the fan for max speed.

I'm not 100% certain of this. Which is why I'm going to go buy a resistor array this weekend and try it out. But I'll be making sure I can return it if it doesn't fix the problem.

[pro_gmh]

Are they independant resistors? I think its strange that resistor 3 is ok and 1 and 2 are not working.

[ProggerPete]

There are 4 pins on the resistor array. My guess is that 1 pin is common and the other 3 pins are connected to speeds 1-3. It is definitely possible for some resistors to go and not others.

Again, I'm not 100% on this, I don't have a circuit diagram but it fits with what I've seen and heard.

The resistor array I'm getting this weekend is $25 bucks and I can take it back if it doesn't fix my problem. My suggestion would be to just try it out.

[S Pack]

mine works on four only ill trade you lol

[ProggerPete]

I can now state for sure that the fan array resistor does ZIPPO for speed 4.

There are 3 resistors in the array, they are connected in parallel as follows.

+---R1---+ F1
|
+---R2---+ F2
|
+---R3---+ F3
|
Common

So in my case where speed 4 wasn't working the resistor array had nothing to do with it. I'm 80% sure the problem was the switch, but seeing as I had already pulled the resistor array out I ran a contact between F1 and the common pin, bypassing R1. So now speed 1 is full ball, speed 2-3 are normal and speed 4 still does nothing. Didn't cost me a cent. =)

I can also tell anyone who's interested that the resistor array off a VS works fine. It looks completely different, but the plug is the same and it works fine.

[pro_gmh]

Why dont you just wire a varible resistor in pin 4, then you will have total control over your fan speed.

[ProggerPete]

Maybe because the resistor array is under the leafguard under the bonnet of the car. Not the most convenient of things to get at.

[pro_gmh]

Yer tru, mines broken and cracked in a few areas, whats under there that water can stuff up? is it sealed under there?

[ProggerPete]

Anything electrical seems to have it's own seal, i think it's main task is to keep water and leaves out of the air vents.