Finding which one is the earth! Now sorted!.

[stevetigger]

Right, I know it seems a daft question to most but how do I go about finding which wire from my electric fan is the earth.

There is a Green, Red and black wire coming from it and when I attach the Black wire to the Neg of a battery and either of the other two to the + of a battery the fan works fine!

Now that I have fitted it all in to my car, the fan doesn't want to kick in.

I am thinking I have picked the wrong colour wire for the earth. I know colour means nothing really, is there any sure way of knowing which wire on my fan is the earth??

Cheers Guys

[ian332isport]

Steve,

What's the fan off ?

Doesn't sound like an E30 fan with those colours either.

Ian.

[stevetigger]

No its not an E30 fan, Got it for a pound off ebay.

Its from a Nissan 200 sx, works great and it's fast too. More than up for the job and fits super neat.

[m-dtech]

but what direction was the fan spinning

[stevetigger]

The way the arrow on the front points!

[BMW_YARD]

Right, I know it seems a daft question.........I know colour means nothing really, is there any sure way of knowing which wire on my fan is the earth??

Cheers Guys

Of course colour means something, it gives an indication of what direction the electrons should be flowing inside the cable!

It should be the easiest thing in the world to get this wired up right.

The way the arrow on the front points!

OK, you know which is the front, designating that it is a 'suck job' or a 'blow job' fan. (ooh err missus).

And you know the direction it needs to rotate from the arrow.

And you had it working out of the car

when I attach the Black wire to the Neg of a battery and either of the other two to the + of a battery the fan works fine

Got to be a muck up when you wired it into the car.

You also don't say, but I suspect that this is a two speed fan, or were you connecting the remaining two wires to positive?

And any way your on the wrong forum, datsun part datsun forum, would make more sense

[stevetigger]

Got to be a muck up when you wired it into the car.

You also don't say, but I suspect that this is a two speed fan, or were you connecting the remaining two wires to positive?

I did it how BMW do it!

It is a two speed fan, I wired one wire to fuse 3 and the other to fuse 18

[ian332isport]

Of course colour means something, it gives an indication of what direction the electrons should be flowing inside the cable!

You what

I did it how BMW do it!

It is a two speed fan, I wired one wire to fuse 3 and the other to fuse 18

I take it you also added both relays and associated wiring for the temp switch etc ?

Do the relays operate when you short out the temp switch contacts ?

Ian.

[BMW_YARD]

I did it how BMW do it!

If you trust your wiring talents are up to the level of BMW then it must be a knackered fan.

Although you have connected it to the fuses, are these actually live (hot) when you expect the fan to work, have you fitted any additional relays that may be required for this upgrade (!)

[stevetigger]

I take it you also added both relays and associated wiring for the temp switch etc ?

Do the relays operate when you short out the temp switch contacts ?

Ian.

I added all the stuff needed. I just had another look and fuse 19 had popped. I put in a 30 amp fuse.

I tried putting a wire stright from the + battery to the sensor but nothing, I thought I heard a pop from the fuse box but the fuse is still in tact!

[BMW_YARD]

As Ian said and typed faster install the relays .

Electron flow = direction of fan rotation, obvious realy, and to the uninitiated the manufacturers kindly colour the wires to help.

stevetigger wrote:
I know colour means nothing really, is there any sure way of knowing which wire on my fan is the earth??

Manufacturers use colours for a reason

[stevetigger]

All relays in!

[BMW_YARD]

[/quote]
I added all the stuff needed.[/quote]

Should work then


Sensor is normally ground side of relay (trigger)

When Ian said short it he meant 'bridge' not connect it to positive (fry)

[ian332isport]

Steve,

Fuse 19 is the feed for the rad temp switch and should only be 7.5A. When the temp switch contacts close, it switches 12v (via fuse 19) to the relevant relay (high or low speed). If you are popping a 30A fuse then you have something wrong with the wiring.

Ian.

[stevetigger]

NO, it popped the 7.5 so I put in a 30amp. And then tried the + wire to sensor trick.


Still no flow.


Thats why I think Ive picked the wrong wire to earth on the fan!

[BMW_YARD]

And any way your on the wrong forum, datsun part datsun forum, would make more sense

[ian332isport]

NO, it popped the 7.5 so I put in a 30amp. And then tried the + wire to sensor trick.


Still no flow.


Thats why I think Ive picked the wrong wire to earth on the fan!

Steve,

Fuse 19 has no direct connection to the fan. If fuse 19 is blowing it's to do with the low current wiring between fuse 19 and the relay's.

You need to get the relays switching correctly before worrying about the fan.

Ian.

[stevetigger]

OK, how do I manage that?

[ian332isport]

OK, how do I manage that?

The description below is based on you replicating the BMW wiring 100%.

Disconnect the temp switch on the Rad, remove both relays and fit a new 7.5A fuse for F19. You should now have 12v (ignition switched on) on one of the pins on the temp switch. If you do, then fine. If not, then you have problem with the wire running from fuse 19 to the temp switch.

Assuming you do have 12v on the switch connector, use a piece of wire and short that pin to one of the other pins. Try this for both of the other pins. If fuse 19 blows, you have a problem between the temp switch connector and the relays in the fusebox.

Assuming fuse 19 is still okay, put the relays back in and repeat the last test. You should hear the relays click when you short the wires on the temp switch connector. If you don't hear the relays click, then you either have faulty relays (unlikely), or you don't have a ground connection on the other side of the relay coil (I think this needs to be added as it's not there as standard).

Judging by your previous posts, I would say you are going to find fuse 19 popping at some point. You need to stop this happening before going any further.

Ian.

[stevetigger]

Thank you very much Ian,


I need to have the fan working before I drive the car on a more permanent basis.

I will try all your suggestions tomorrow as I am running out of light now!
Hopefully, I have just wired it wrong'ish and can sort it straight away.

I can see me going through a lot of 7.5 brown fuses tomorrow finding the fault.

The joy of modding!

[stevetigger]

Right, been out to sort the fan.

I replaced the 30A fuse in F19 with the correct 7.5A.
Then I did the above mentioned by Ian, still no joy.

Then the wife brings me a coffee and asked me why I have a little wire running from the battery + to the temp sensor. I said to short it out, thats when I noticed I should be going to the switch no the sensor.

What a fool I feel now, so all in all it works fine.....Once I run the little wire to the switch, all the fuses fine and all the right clicks.

I started the car and gave it some revs, guess what.......FAN worked a bloody treat. Nearly blew my wig off.

Thanks again guys for your help. Thanks Ian.

I think it must of been the blown fuse in 19 in the first place making it not work!
You live and learn.

[BMW_YARD]

When Ian said short it he meant 'bridge' not connect it to positive (fry)

Maybe your wife has been reading my help I gave you yesterday.

You should only work as fast as you can read and understand!