Cooling Fan

[suth82 0]

i know this topic has been covered several times but iam looking for a wiring diagram for installing a second cooling fan, iam sure i've seen one on here before but i've done several searches and not been able to find it, if anyone could point me in the right direction , it would be much appreciated.

 

Paul

[jonnie205 1]

It depends if you want it wired on a swith or just wired in on the existing thermostat controlled wiring?

[suth82 0]

i would like it to be wired to an internal switch

[Wurzel 16]

This isn't hard at all mate. If you can grasp the circuit needed to turn on a light using one switch then you can wire in this circuit.

 

You will need a switch, two blade fuse holders, a second fan, a basic relay (look at the fuse box in the car and you will see some of the type you require. A scrappy will have loads) and some wire.

 

This is just ONE method.

 

Basically:

 

1. Run a short length of wire from the positive side of the battery to one of the fuse holders (about 30cm or so in length). From the other side of the fuse holder run the wire to the switch.

 

2. From the other side of the switch run a wire to the relay. It needs to connect to spade number 85.

 

3. From spade number 86 on the relay, run a wire to an earth point.

 

4. Run a wire from the positive side of the battery to one side of the second fuse holder (about 30cm in length). From the other side of the fuse holder, run a wire to the relay and connect it to spade number 30.

 

5. From the relay spade number 87, run a wire to the fan unit.

 

6. From the other connection on the fan unit, run a wire to an earth point.

 

Points to note:

 

1. You will need a fuse with a rating of around 1 amp for the switch fuse and therefore the wire you use here should be of similar rating.

2. You will need a fuse with a rating of 25amps for the cooling fan fuse and therefore the wire again, should be of similar rating.

3. You will need to experiment with the positive and negative connections on the second fan so that it rotates in the correct direction (suck air into the engine bay rather than blow it out).

4. Don't put the fuses in until you have completed the job!

 

A good supply of wiring, switches and relays is below:

 

Vehicle Wiring Products

 

Piece of piss.

Edited February 18, 2004 by Big Nick

[suth82 0]

cheers for the answer Big Nick, i have a good picture in my head now - advanced cooling on its way soon me thinks!

[Wurzel 16]

Glad to be of help. There was a pinned article with pictures of how to wire in twin fans that were automatically activated by the radiator temp switch. The circuit diagram was from a turbo diesel and although it looked complicated, it was exactly the same principle of switches.

 

Relays simply allow a small current (your switch) to isolate and handle a larger current load (the fan).

 

The engine shouldn't really be getting that hot though. Make sure there are no other problems that you're simply masking with the extra cooling fan.

 

Incorrect water/coolant mix, air pockets, duff thermostat, duff radiator temp switch, low speed fan circuit tits (usually resistor unplugged or something). All or one of these can lead to excessive temps.

 

If you just want the extra fan then by all means have a go. I found it useful when sat in motorway traffic during the summer.

[suth82 0]

there isnt a big problem with the engine temp, it sits pretty cool while cruising but i often get stuck in traffic coming home from work and the temp begins to get high, i would just like an extra fan as a bit of assurance, as the fan once failed on me cause the earth wire was corroded, so it would be good to have a back up in the event of it failing again.

 

Paul

[Wurzel 16]

That's what I thought. I did the same and although I am under no illusion it will add 10 bhp to the engine, like it. Gives the confidence that the now very old coolant pipes are under a little less stress from splitting due to the high temps.

 

Any way, any probs, pm me.