Sierra cosworth fans not working

Ok ive checked the wiring and the fuze.
I even took out the fan connector at the temperature sensor and bridged them.
The fans worked till last week and came on at the correct times.

My coolent fans don't kick in when the temperature rises.

Don't now on this as I'm quite good at fixing things.

I have a MSD new wiring loom fitted a year or two ago.
There does seem to be a free connector underneath that looks identical to the crank sensor underneath.

Ive asked about these in the past and MSD come up with utility connectors for trick stuff.


My fans don't work and they should.

I would like to know wich relay it is as the Haynes manual doesn't tell me.
Thankyou

 

I would check you have power to the switch connector, the relay is a yellow one.

You best of rewiring, as it's a bad design.

The standard switch has a span which results in the fans coming on too early and for to long, this is what results in the fuse and box melting.

Another benefit is it alleviates the load on the fuse box, which is overloaded.

Martin

 

It's got a new MSD wiring loom which cancels out all the 10.2 v problems.
Theres no yellow relay any more.

I bridged the rad sensor and it didn't work.
What is the relay in the fuse box that I could change.

 

I appreciate that, but all that does is eliminate the switch.

As I say, you need to see if you have power there.

I didn't know it had been rewired, but as you say the OE wiring and components are no longer used, the relay should be part of your new loom?

Martin

 

i am getting there ,I'm under it now.
I will get the volt meter out and keep checking.
I have read the wiring diagram in Haynes.
It seems to be a negative earth scenario.
it could just be a earth connector.
Thanks i'll prod on.
All I do with the relays is swap them about and see if that shakes something up.
I had checked the fuses earlier.

 

the switch has voltage a very tidy 14.2.

I bridged the connector.

That didn't work.

Abrown and black and a brown.
I even re earthed the brown.

Its were the black and brown wire goes.

It is a relay.

Thing is I think its under the bonnet the relay.

The MSD relays are marked up and its not one of them.

The big green ? wires are about 30 amp.

It must be under the bonnet fuze box.

 

Not necessarily, can you hear a 'click' when you bridge the connector?

The switch completes the ground for the relay, thus tripping it and activating the fans.

Martin

 

No.

All I need is the relay now.

Which relay is the cooling fan relay competition.

I have earthed out the switch.

I did not hear a click.

If I could find the relay.

The 2 yellow ones were fuel pump and maybe ecu.

Why isn't it in the Haynes manual?

One the fuse box lid it just calles them 1-10 in roman numerals.

 

Ok I think I know a solution.
I am going to get wasted spark before the end of the year.
I will get the uprated fan loom kit at the same time.
I do have a magnificient new engine bay loom by MSD.
I just read the add and the cooling wiring loom was a optional extra.
My bad I will just get the lot done.
Its only if I sit with the engine ticking over for say 10 mins there is a overheating problem.
once I get going she self cools.
Still wouldn't mind swapping over the relay until then.
On one of the pictures in Haynes it goes on about a fusable link but I have a positive to the switch so it is a relay issue.
Don't think its burn't out as the wires were big 30 amp stuff.
It'll be a relay just need the right person to read this as I'm sure anyeone who's had a cosworth will have chased this problem.

 

So it's not rewired then.

In that case, it's the yellow relay in the fuse box.

How have you determined the fuse is ok?

No, the fact you have power to the switch connector means the relay has power, it does not mean the fans supply is present.

It's possible the relay has got 'stuck' as well.

Martin

 

I'm going to change the yellow relay in the fuse box.

I have spares

Thankyou very much for your help martysmartie your help was spot on

 

Ok changed the yellow relay.
When I bridged the switch ,I could hear the relay clicking.
Still no power at the fan cable.
I have ordered a MSD loom.
It'll be here in the morning.
That will take about 15 mins to wire up.
Should be good bye then.