Carrying on from my other thread:

https://passionford.com/forum/ford-e...ml#post5936140

couldnt get my sniff tester to check for a head gasket today so decided to drop the coolant out and bleed the system up again, ran the car up and noticed the fans werent kicking in.

So i went to check if the fans worked by bypassing the fan switch, pulled the plug off and found this:



It now runs as it should and the pipes arent feeling like they are about to burst

BUT: this is the 2nd fan switch i have fitted in 2 months, and as you can see its got VERY hot!!

Has anyone ever had these issues before with a fan switch? as i dont want to cover up the problem by bypassing the switch....

Cheers Adam.

 

Sounds like your fan maybe drawing too much current through dude, is it a standard fan,

 

was just about to say, why`s it melting switches..........

fan possibly on its way out drawing too much current?

check resistance of wiring too before and after switch

 

is the rest of the wiring ok ,had some melting issues a few inches up from the switch before ,worth a look ,think they sell the connector with a couple inches of wire on ebay ,,maybe of some help maybe not ,

 

It has 2 airtec fans fitted bud which came with my AIRTEC FMIC

Will give the resistance a check matey

Yes, when i rebuilt the engine we took all the old electrical tape off and checked for breaks in wires then retaped the whole loom, nice one will have a look for the plug.

 

Good old MSD

http://cgi.ebay.co.uk/ws/eBayISAPI.d...#ht_2728wt_762

 

msd do a uprated fan switch for 20 quid or so which makes the fan come on a little earlier and go off a little later. But for your switches to be melting means that your fans are ddrawing too much current. Then only drawback with the msd fan switch is that your fans are on more often and if you have a problem with your fans or wiring will just amplify it somewhat which could lead to burning out again. Has your rad got plenty of clean air as you say you got twin fans means you got a full front mount is this totally obstructing the rad

 

valid point on the front mount above,

chop the old fan wiring out as much as you can back to the fusebox, or make a sub loom from new good quality wiring, then with the new reostat the job is jobbed!

if you have the cash, get a new or upgraded/ally rad to help things also as the fans shouldnt be on all the time anyway

 

Yes mate blocks most of the radiator, might try the switch and see how i go...

Heres a pic of my rad/cooler set up

 

The switch merely trips the relay, its the fan wiring which would melt, you/someone haven't wired the fans directly to the switch?

Martin

 

I also have a big front mount (grs) which is also in a fiesta. Like I said my fans have been coming on earlier and for longer periods because of the decrease in amount of air available to the rad for cooling. The fans which come with these intercoolers are not always that much kop and couild be causing the burning of wires. I would replace the fan switch and fan and check all wiring to the fan and if that don't sort well I am stumped

 

pretty sure there isn't a relay standard on these cars, on my Sapphire there wasn't on the standard loom, so the switch takes the full current.

 

Looking at your pic you can see why your having trouble because very little air would be hitting the rad. Is it possible to put the rad up front or another downsize the cooler ? Everything is tight looking at that and somehow you need to make space so the rad can get the cold air it needs otherwise you will never stop the overheating problems and it could kill your engine if it not sorted.
Your fans must have been working overtime trying to cool the rad and the standard wires for it would get hot after a long time of running so it then melts. Another option is to run the fan on a switch inside the car but using the correct wire and relay so that you dont have the problem again.
I have fitted a few switches to big bhp cars over the years and never had a problem doing it this way aslong as you remember to flick the switch when the temp starts going up. Only down side to this is the noise when your doing 20 mph along the sea front with your arm on the window....... lol

 

If you're running twin fans mate you'll need to run them via a relay and a new circuit with thicker gauge cable...can mount the relay in the engine bay, and i'd add an override switch in the car somewhere convenient so you can flick them on before the car gets hot or if sat in traffic.
You can use the exisiting wiring to trigger the relay

 

relay XI in the main fuse box is the relay for cossie fans.

 

It does, it's in the fusebox.

Putting this sort of current through the switch will cause the exact dangerous issue the OP is having.

Martin

 

As dave says, new wiring from the battery, relay etc it will be fine.

My turbo cab has twin fans, my pal re wired it with a relay, seperte fuse box, optional over ride switch. It's all good.

My standard fan switch will soon be done away with as my ecu will control the fan

 

Anyone got a wiring diagram for an over ride switch for the fans? Quite fancy one as my pace cooler is huuuuge!!

 

It's quite simple, just run a connection from the fan switch to a switch and the other side of that to ground.

Martin

 

ive had this years ago, my fan motor was seizing up, does the fan spin easy by hand ?

 

both my escort and cossie had the fan changed via a secondary relay switching circuit, it deffinatly helped by not over stressing the "normal circuit" of having aftermarket fans fitted to ageing wire looms.

 

Use a piggy back connector? Will the fans still work normally? Sorry if this is obvious wiring was never my strong point and my mech was on about relays and stuff!

Cheers for the help!

 

Yes it will do what you want, i.e. an OVERRIDE switch, so the fans will cycle via the switch as normal.

You can use a piggyback connection, by this do you mean a 'Scotchlock'?

It's just to run another connection from the wire from the relay side which goes to the fan switch.

That is all thats needed, you don't need any other components.

Martin

 

Don't you dare use blocks mate they are very dangerous with the amount of current runnin through them and melt and touch together whcih will cause problems again and then you will have no fans again

 

Thats completely not true!

The high current side is via the relay and the wiring to the fans, the wiring to and the switch itself merely completes the ground side of the relay, thus not alot of current!

Martin

 

amazing. the number of people that can't understand a simple relay circuit

 

All sorted since the dodgy fan switch was discovered, bypassed it untill my bits arrive and am being very cautious, me and my mate are fitting a 2 stage manual fan switch system with the neccesary relays and wiring.

 

Make sure its a protected circuit
I would of thought 25-30amp fuse should be safe

 

Its 30 amp mate

 

Just as I thought then mate! Thanks very much! Won't be using scotch locks though! They look pikey as fook! Ha!