In car fan overide switch help

[HULK]

Hey peeps

wired up a override switch for my rad fan last night and it worked fine, but drove the car today and the fuse blew

basically I put a single wire from the positive on the radiator to a switch in the cabin and then put a live feed to the switch via a 10 amp fuse but the fuse blew.

Have I wired this ok and is the fuse just too small??

Jim

[Ashy]

Hey mate, best to wire it up direct from the radiator switch? Simplify the wiring using a live and earth from the alternator.

If you do want to run a fan switch in the car it would be better to feed the fan with +12v from the alternator and fuse it, then switch the earth by running the earth from the fan into the cabin then ground it behind the dash. That way if the wire shorts out somewhere all that will hapen is the fan will turn on rather than you blowing a fuse or having a fire!

[HULK]

Thanks Niall. What I have done is solder a wire to the existing positive feed on the rad fan switch itself and ran that to the cabin switch and then put a +12v feed to my new cabin switch. Do I need to cut the original +12v feed to the rad switch??

I'm thinking that the fan was maybe working when I hit my override switch and that blew the fuse??

[THE MASTER]

there is an easy way .. piggy back the termials on the rad switch . and simply run the two wire into the incar switch .

[Jimmy_GTT]

Thanks Niall. What I have done is solder a wire to the existing positive feed on the rad fan switch itself and ran that to the cabin switch and then put a +12v feed to my new cabin switch. Do I need to cut the original +12v feed to the rad switch??

I'm thinking that the fan was maybe working when I hit my override switch and that blew the fuse??

No, I don't think so. If it was already working than you had +12V on both terminals of your switch. If you short the switch it can't blow the fuse.
As I remeber these fans are taking 8-9A under normal working conditions but when they are starting there is a peak which is higher. I would try to change the fuse to 15-20A. Ang give it a try.

[Jimmy_GTT]

Hey mate, best to wire it up direct from the radiator switch? Simplify the wiring using a live and earth from the alternator.

If you do want to run a fan switch in the car it would be better to feed the fan with +12v from the alternator and fuse it, then switch the earth by running the earth from the fan into the cabin then ground it behind the dash. That way if the wire shorts out somewhere all that will hapen is the fan will turn on rather than you blowing a fuse or having a fire!

But I think with this solution the radiator switch won't be able to turn on the fan, will it?

[tiff_lee]

I would not of thought it was ideal to supply the fan via a switch rather than a relay? As the master said you could just short the rad switch terminals via the switch turning the fan on.

You could even wire the fan to a single 4 pin relay via the alternator and fan switch and include an overide switch to energise the relay.

[Brigsy]

Manual switch for the fan aint needed mate (assuming it all works as it should), save your time & effort fitting one

[clee]

If the temp sensor in the rad is working correctly then no point putting in an override .

[clee]

ahh ! yeh! wot he said

[J$£5GTT]

buuuuuuuuut if your out an about an everything stops workin as it should you can if needed over ride it..

[Chris Hebden]

Then bridging the wires at the rad fan switch would get u home if needed!

[J$£5GTT]

Then bridging the wires at the rad fan switch would get u home if needed!

used to do that in my old astra gte

[HULK]

The rad comes only but only for about 10 seconds which isn't sufficient time to cool things down