Temp sensor question

[fastivaca]

Which temp sensor controls the cooling fan? The one in the thermostat housing or the one in the head?

Thanks

[SiliconSoul]

Pretty sure it's the front one Ian. Back one controls fuel.

[Basement_Modder]

Tstat housing one

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[ryanprins13]

Yup, thermostat housing. Unplug it and it should come on. The fan that is.


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[bravekozak]

The one in the cylider head goes to the temp sender in your cluster.
There is no reason for the rad fan to come on before the thermostat opens.

[fastivaca]

Thanks for the replies gents. I've had a chance to look at the Festiva EVTM and it appears that the cooling fan temperature switchboard the one in the head...



...and the coolant temperature sender is in the thermostat housing...



This seems to be the reverse of what you're telling me! Help!

[ryanprins13]

The fan turns on with it unplugged. Just unplug em and whichever one turns the fan on is it!
Are you having a problem with yours?


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[fastivaca]

The fan turns on with it unplugged. Just unplug em and whichever one turns the fan on is it!
Are you having a problem with yours?


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Fan isn't coming on at all. I'm going to be checking connections over the weekend. I've lost my DRL's as well... seeing the relays for both are right next to each other I think those issues might be connected.

[FestYboy]

Ian, the temp sensor is in the head, it sends signal to the cluster. It is also too small to be a thermal switch. Can be verified with a multi meter as all it is is a thermistor for the sensor ground. The switch in the t-stat housing controls the low side ground for the fan relay. The lack of ground on that leg allows the main switch to close, which is why when you pull that plug, the fans are energised.

[bravekozak]

You are not supposed to wrap teflon tape around the head sensor. The head itself is the ground.

[TominMO]

What manual is that, Ian? Haynes?

My 1991 Ford factory Festiva shop manual shows very clearly on page 03-01-10 a diagram for removing the thermostat. In it, the item in the t-stat housing is the cooling fan switch. I'm guessing your book just got it backwards.

[ryanprins13]

Temp sensor question

Fan isn't coming on at all. I'm going to be checking connections over the weekend. I've lost my DRL's as well... seeing the relays for both are right next to each other I think those issues might be connected.

Yup, Check the relays. Mine always worked, i unplugged the relay and plugged it pack in and it didnt work. Took it back out, cleaned the contacts a bit and put dielectric grease on it and it worked just fine.
For the drl's turn the key on, make sure everything is quiet and touch the rear wiper fuse on and off its contacts. You should hear the relay click when you do that. If not the problem is the relay or wiring before the relay. If you do hear it and the lights dont come on the problem is after the relay.
With the fan you should hear the relay click when you touch the wire going to the sensor on and off the sensor. I presume you dont so the problem is the relay or before it rather than the fan.