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I have just purchased a heated windscreen for the fender and am about to fit and wire it up. I will be ordering two of the PRC 7303 relays from LR series but the wiring diagrams i have from previous posts on this site talk about a timer unit. I cannot seem to find one listed on LR series. Does anyone know what unit i should be looking for and where best to get it?

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I hope Paul won't mind me posting on here as it seems a bit silly to start another heated windscreen thread when there's already one running :)

I've just bought the latest 2 connector type screen. Looking at the TD5 wiring diagrams in rave I've noticed that the main power supply for the relay is fed through a 30 amp fuse. Is it safe to assume then that I would only need a single 30 amp relay for it ?

I got the impression from earlier threads with people using 2x 30 amp relays on the 3 tab screens that these draw heaps of power or are the new screens more efficient ?

TIA

Mo

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  • 1 month later...

So i am now finally ready to wire up the screen. The timer relay from VWP is to be wired as the diagram. Terminal 3 from the battery i will fuse with at least 20 amp. Would i be right in assuming terminal 4 +AC would come from something like the oil pressure switch so that it only operates with the engine running. 2 and 5 to earth and i assume 1 will feed the two 30 amp relays which i will use to power each side of the screen. I am getting a bit confused because the screen wiring diagram i have found which shows using a timer relay has different terminal numbers to mine. Any help would be grtatefully appreciated as i would like to get this wired soon now that winter appears to have arrived. I will also be using 30amp rated cable for live feeds.

Timer relay.pdf

post-6497-050267700 1290958252_thumb.jpg

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"The timer relay from VWP is to be wired as the diagram."

Which bleeding diagram? You have attached a pdf and a jpg showing different layouts.

As a point of principle, use one or the other, don't try to mix and match.

You assume and assume and assume, because the diagram isn't clear.

Go back to the supplier of the diagram and suggest they do the job properly. Force them to answer clearly the points which aren't clear to you.

This stops us having to guess or assume for you, and tells the supplier that they supply carp information, thus giving them the chance to put it right, and make it suitable for purpose.

We aren't paid to act as consultants to VWP. They charge enough for their products, make them supply the service you have paid for.

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I hope Paul won't mind me posting on here as it seems a bit silly to start another heated windscreen thread when there's already one running :)

I've just bought the latest 2 connector type screen. Looking at the TD5 wiring diagrams in rave I've noticed that the main power supply for the relay is fed through a 30 amp fuse. Is it safe to assume then that I would only need a single 30 amp relay for it ?

I got the impression from earlier threads with people using 2x 30 amp relays on the 3 tab screens that these draw heaps of power or are the new screens more efficient ?

TIA

Mo

Mo,

Mine runs through 40 amp fuse and I use a 70 amp relay just in case....

Neil

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In reply to Paul H, the VWP relay is not a direct replacement for the Landrover part and works in a different way.

The reason for this is that the rear windscreen heater which the VWP relay is designed for only takes about 75W (~7A) and so it is less critical to turn it off when it is not needed, whereas the front windscreen heater on the Defender is about 300W (25A) so you really only want it on for a short time and only when the engine is running or you will end up with a flat battery, particularly if you are using the vehicle at night.

The Landrover windscreen timer uses the signal from the oil pressure light switch to confirm that the engine is running, as well as only allowing the heated windscreen to run for about 10 minutes after the switch is pressed. This ensures that the great unwashed who don't understand the first thing about vehicle battery loadings can't leave the heater on forever and then complain when there isn't enough juice in the battery to start the engine from cold the following morning. However, for anyone who does have an inkling about battery loadings, it really isn't too much to expect them to only run the heater for a short time and remember to switch it off manually.

The VWP relay has no means to detect whether or not the engine is running - it's just a relay with a timed latch. You can achieve the engine run detection by powering the WVP relay off the voltage sensitive switch which is already fitted on the 2.5TD - 300TDI models as part of the heated rear window circuit.

In fact, I'm also about to fit a heated windscreen in my 90 and I intend to run it off a relay which I will activate from the heated rear windscreen circuit. The power side of the relay will come from the battery via a 30A fuse. This means that the front and rear windscreen heaters must be on together or not at all. Since I hardly ever use the rear one (in fact I don't think it's been working for quite a while) I can't see a problem with this, and I like the idea of not having to add any more switches or controls to my dashboard.

If you want to ry to make the front and rear heaters independent of one another then you will need a separate switch for each one (obviously) and you will also need to do a bit of jiggery-pokery with the wiring for the voltage sensitive switch. ICBA to advise on that at this time of night having been out in the cold all day re-building my rear tub, but drop a reply to this post if you need more advice and I'll see what I can do for you tomorrow.

Nick.

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Hi Nick,

Thanks for the info. That certainly explains things a bit better. I have a mud console and have already got a switch for the screen fitted to it so will be looking to go down that route. I am happy not to use an engine running supply as i have wired the switch with a warning light and am pretty anal about switching things off (been caught to many times when younger). Just need to get my head round powering the two feed relays from the timer one.

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Challo, Ive not used them myself, but this company sells them...

http://www.heatedwindscreen.com/acatalog/land-rover-heated-windscreens.html

This company used to sell them, but their site is under development currently..

http://www.beamends-lrspares.co.uk/

and this is worth reading..

http://www.lrm.co.uk/Archive%20Index/Technical/Fitting%20a%20Heated%20Screen/fittingaheatedscreen.html

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Ayup, i'm after a heated windscreen for my defender. Could you please tell me where you got yours from? Cheers in advance.

I got mine on my insurance :ph34r: when they asked over the phone if it was heated the word 'yes' just slipped out :lol:

cost me £25 excess :) and a little bit of wiring which i did myself. no one ever questioned it.

Steve

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Can one of the wiring gurus have a look at this and see if they think it might work

No, you've got the battery shorted through the VWP relay if you do that. If you're lucky you'll blow the fuse. If you're unlucky you will set fire to the relay.

Not got time to provide an updated diagram right now, but will get back to you later. What did you do your diagram in? It might be easier to modify what you have done than produce a new one.

Nick.

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I got mine on my insurance when they asked over the phone if it was heated the word 'yes' just slipped out

cost me £25 excess and a little bit of wiring which i did myself. no one ever questioned it.

Steve

Much appreciated for that Steve, i like your way of thinking. Think i'll give that a whirl and when they ask if its tinted, who knows another yes might slip out too.

Cheers

Chris.

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