Hi,

I am intending to install heated windscreen wash jets in my 14 plate Fiesta Titanium Keyless ignition. I have the jets and loom from a 59 plate Focus. On the Focus the heaters are on all the time the engine is running and the supply is taken from the ignition overload relay R8 and shares a fuse with the wash pump. I would like to do something similar but only have them on when the heated rear window is on. I bought the new Haynes Manual (6407) for my car but the heated rear window circuit isn’t in it and I can’t see anything like an ignition overload relay.

Does anyone have a wiring diagram of the ignition and heated rear window circuits?

Thanks.

I have contacted Ford Tech services to try to get a wiring diagram of the Heated Rear Windscreen for my 2014 Fiesta. No joy. I have to subscribe to Etis. Not sure how much this is but as this is possibly the only time I would use it, it hardly seems worth it. I am a bit miffed as after paying a considerable amount for the car the support from Ford is dire. 

I don't think there's a dedicated (separate, external) relay for the heated rear window but rather it is switched internally by the BCM (pin 9 output specifically). You could tap in to this - it is located somewhere behind the glovebox.

However, given the size of the washer jets I can't imagine the heating elements draw all that much current and so perhaps the always-on mode of the Focus isn't too bad an approach? Or am I missing the significance of what is meant by the term 'ignition overload relay' (it is not something I've heard of before)?

You could measure the current draw with a multimeter to satisfy yourself that they may as well be on constantly. This may even work better given that the heater rear window would tend to be turned off after a while yet the risk of the jets freezing up might continue throughout a journey. I suppose the heat from the engine tends to prevent this in practice.

Hi, Yes I think you are correct. I am trying to make it more complicated than necessary. I straight feed from an ignition live would fine. The 'Ignition overload relay' is in the circuit for the Focus. The Focus forum has a complete set of wiring diagrams available to down load. I found these very useful when I had a Focus.