Wiring Heated Screen

[mickie 3]

been searching but can i hell find the topic, im sure i seen it a while back

 

could someone please post the link if they know where it is.

 

thank you please

[jackherer 543]

Do you mean a heated front screen? I have wired them up via a relay triggered from the heated rear window switch to keep things simple.

[marksorrento205 80]

From what I remember its two relays, one either side of the screen. I would fit a timed relay to stop buring out the screen if left on. Im still yet to fit mine

[jackherer 543]

There are two elements with connections either side but they can both be run from one relay as long as it is rated for the current the screen drains.

[GilesW 41]

What current does the screen drain (I've got one ready to fit)?

[mickie 3]

yeah heated front screen, what current does it drain off, my screen came with no instructions..

 

also the screen has 4 wires, do you connect one wire on the right side to an earth and the other direct to a relay ? then to 25a fuse?

 

the other side doing the same or is one side earths and the other positives ?

a friend is going to be making up a new loom so probably wont be using the wiring from the rear screen.

cheers mark, it'll get those timed relays then

[large 33]

To work out the current drain of the screen you will need to measure the resistance of the heating element with a multi meter. When you have this you can work out the current by dividing the resistance by the voltage. I= V/R.

[mickie 3]

ive just read alwhere, about using 2 20 amp relays , 20 amp fuses but there are loads of combinations, so which is it we need ? hmm

[mickie 3]

cheers large that helps a lot

[mickie 3]

or maybe not, i get 19.7 ohms on the passanger side, 10.5 ohms on the drivers

[mickie 3]

i dont fully understand what to do with those ohms readings so i just measured what the screen was using direct off the battery

 

earth direct to the windscreen/battery and possitive through the multimeter/battery

11.40a direct off 12v battery

 

im thinking its best to have a relay for each side as if i had one big 30a relay and one side of the window failed wouldnt that just send too much to the other side ?

 

2 20a relays using 2 15a fuses, should do it ?

Edited July 15, 2010 by mickie

[jackherer 543]

I've been running a heated screen off ONE relay for ages, I don't remember how many amps the relay is rated to, but you just need to look at the thickness of the wiring to the screen to realise it is not a crazy amount.

[marksorrento205 80]

Dont know if you have seen these. Can you tell im bored at work

 

If you have no heater box then yes very good to have.

 

As for Autoglass, I'm sure if you ring a "local" glasier (sp??) they could do one cheaper than them they were stupid when I needed a screen a while back. But if you want a heated screen then yes easy to wire up, usually have a left and right element, you'll need some decent gauge wire as they can draw a couple of amps and a timed relay is a good idea to put in (from a 306 rear heated screen relay for exmaple or ford forn screen relays) to stop it being left on and burning out prematurely.

 

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