JonR Posted October 23, 2006 Share Posted October 23, 2006 I'm getting a heated front screen fitted soon and I'm in the process of installing the wiring for it. I've got the relay and switch side sorted but I need to find a suitable power source for the screen. LRO mag covered this installation a few months back but the article suggested wiring from the battery with an in-line fuse up to the relay but I'd rather use a suitable ignition controlled power source (wire) near the fuse block but not certain about which one to use. Also, what type/size of connection is used on the windscreen? Presumably its some kind of tab. Thanks in advance. Jon. Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted October 23, 2006 Share Posted October 23, 2006 Seeing as the screen will draw quite a lot of current, i'd advise running a beefy cable direct from the battery, going through one of the maxi fuses (you could run it near to where your existing fuse box is, or if yours is a 300Tdi, get a military wolf under bonnet fuse box, as they have about 4 more fuses, you could use one of those) Then take an ignition fed live, and use this to control a relay to cut the power to the screen. better still.... take a feed from the heated rear window switch (assuming yours isn't a truck cab or soft top), as this is already ignition controlled. you could even, if you wished, wire it so that the front and back heated windows come on together, although a separate switch would be better. Quote Link to comment Share on other sites More sharing options...
JonR Posted October 23, 2006 Author Share Posted October 23, 2006 Jim, thats pretty much what the LRO article said, but they also added that the electrician that fitted theirs used a "thick wire at the back of the fuse block"....but they never said which one Yes, I've just realised that it doesn't need to be ignition controlled since the switch side is anyway. Mines a 200Tdi (retro fit) HT and the relay I'm using is 30 amp with a combined fuse which fits neatly on the fuse board with the other relays. There is a thick (size?) white cable that languishes behind the radio that seems to be a spare of some description. Anyone have any idea where it comes from or what its purpose is 'cos I can't see it on my wiring diagram, it is original circa 1987. Jon. Quote Link to comment Share on other sites More sharing options...
western Posted October 23, 2006 Share Posted October 23, 2006 Any of the White or White/Red trace wires are ignition controlled.you could come off the back of the ignition switch. on my heated screen the connectors are 15amp male spade terminals/strip. Quote Link to comment Share on other sites More sharing options...
JonR Posted October 23, 2006 Author Share Posted October 23, 2006 Thanks Ralph. Don't know, size wise, what a 15amp spade looks like. What is the dimension across the flat? I've discovered the white cable on the composite diagram at last (should have gone to spec savers ) so will use that for power to the switch. I also have a brown spare in the same place which (according to the wiring diagram) is part of the circuitry that eminates from the positive terminal of the starter solenoid and eventually ends up at the ignition switch, so, I think, it should be more than enough for power to the screen. From what I can see, the only other components drawing power from that circuit are the hazards and cigar lighter.....unless anyone could advise me otherwise. Jon. Quote Link to comment Share on other sites More sharing options...
western Posted October 23, 2006 Share Posted October 23, 2006 I5amp spade connector [male bit] is about 6mm across it's width of the spade, often found with blue sleeve or full insulated cover The thick brown from the starter will be fine, more than upto the job. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted October 23, 2006 Share Posted October 23, 2006 My heated screen that I fitted to my old 90 pulled in about 30 amps so I put a feed direct to the battery Quote Link to comment Share on other sites More sharing options...
JonR Posted October 24, 2006 Author Share Posted October 24, 2006 Thanks for that chaps. I'll let you know how it all works out. Now all I need is for some bits to turn up from VWP and.....the rain to stop. Jon. Quote Link to comment Share on other sites More sharing options...
JonR Posted November 22, 2006 Author Share Posted November 22, 2006 Well I finally got the screen fitted today, it was an insurance job so only cost the £50 excess. The only thing is I was expecting to get a Uroglass screen but instead I got a genuine LR/Pilkington screen, which is great but... it has 3 tabs for connecting the wiring to; 2 each end and 1 in the middle. Anyone have any idea why? I asked at my local LR dealers but they didn't know. I'm thinking that I should just ignore the one in the middle. Jon. Quote Link to comment Share on other sites More sharing options...
Kev Baldwin Posted November 23, 2006 Share Posted November 23, 2006 DON'T ignore the terminal in the middle!!! Without it, your screen won't work... The screen heating element within the glass is split into two seperate halves. The two terminals in the corners of your new screen feed the respective heating elements at each side of the screen. These should both be connected to the pos/live feed from your switch and should go to the bottom corners. The single terminal in the middle connects to neg/earth. Kev Quote Link to comment Share on other sites More sharing options...
JonR Posted November 23, 2006 Author Share Posted November 23, 2006 DON'T ignore the terminal in the middle!!! Without it, your screen won't work...The screen heating element within the glass is split into two seperate halves. The two terminals in the corners of your new screen feed the respective heating elements at each side of the screen. These should both be connected to the pos/live feed from your switch and should go to the bottom corners. The single terminal in the middle connects to neg/earth. Kev Thanks for that Kev. I've just been out and had a proper look and can see the small gap at the top (I really must go to specsavers). Forgot to mention yesterday, at the dealers, I had a look at a year old 110 with a heated screen and that only had the two connections at each corner. Is the third connection is a recent modification? Jon. Quote Link to comment Share on other sites More sharing options...
gruntie Posted November 23, 2006 Share Posted November 23, 2006 A heated screen expert I spoke to recently (about custom-made screens for a different vehicle entirely) said that splitting the elements into two sections like this enabled a faster warm-up. However - it came with a warning, in that heated screens - especially of this type - should be wired thru a timer relay so that they are turned off automatically after a short period. If they're not, and are left switched on for extended periods, the elements start to break as they effectively over-heat. This echoes my own experiences in the 90, where I gradually get more and more foggy stripes on the screen that either take a long time to clear or don't clear at all. I'm now on my second screen - needless to say despite best intentions it tends to get left on constantly at this time of year. I'll shortly be exploring the warranty situation (bought from main dealer, but installed myself), though I haven't found a suitable timer relay yet. Anybody got any ideas, pls let me know! Quote Link to comment Share on other sites More sharing options...
western Posted November 23, 2006 Share Posted November 23, 2006 My heated screen is a Pilkington/LR one with the 3 spade connectors, I've got these at the top, got the genuine loom & a SWF illuminated/iconed switch but haven't wired it in yet, I need the correct timer unit first. Quote Link to comment Share on other sites More sharing options...
western Posted November 23, 2006 Share Posted November 23, 2006 Gruntie --------------- though I haven't found a suitable timer relay yet. Anybody got any ideas, pls let me know! heated screen timer RR Quote Link to comment Share on other sites More sharing options...
gruntie Posted November 23, 2006 Share Posted November 23, 2006 heated screen timer RR Brilliant - thanks v much. Quote Link to comment Share on other sites More sharing options...
JonR Posted November 24, 2006 Author Share Posted November 24, 2006 I did think about fitting a timer after seeing this; VWP-Timer relay I'll definately fit one now though. So presumably this one would be ok, despite being significantly cheaper than a genuine one. Jon. Quote Link to comment Share on other sites More sharing options...
rob90 Posted November 16, 2007 Share Posted November 16, 2007 Hi, Im about to have a heated window fitted through my insurance and woul like to have the wiring in place before they came to do the job could some one confirm if the wiring connects to the screen at the bottom/top and drivers or passenger side? thanks rob Quote Link to comment Share on other sites More sharing options...
ozzie1989 Posted November 16, 2007 Share Posted November 16, 2007 This echoes my own experiences in the 90, where I gradually get more and more foggy stripes on the screen that either take a long time to clear or don't clear at all. I'm now on my second screen - needless to say despite best intentions it tends to get left on constantly at this time of year. My 2004 Defender has a heated screen (fitted from factory) that's on a timer. Trouble is it shuts off after 3 minutes, and clears nothing but a few small stripes on the drivers side. Putting it on again for another 3 minutes helps, but is still stripy as you describe! Are they really this sensitive to over-heating do you think? rob90, my heated window is connected on both sides at the bottom of the screen. I would assume the +ve is on the drivers side as this clears the quickest. Quote Link to comment Share on other sites More sharing options...
rob90 Posted November 16, 2007 Share Posted November 16, 2007 Mr Western, what is the part number for a heated front screen on a 1996 300 tdi defender????? thanks rob Quote Link to comment Share on other sites More sharing options...
western Posted November 16, 2007 Share Posted November 16, 2007 Mr Western,what is the part number for a heated front screen on a 1996 300 tdi defender????? thanks rob 1996 Defenders didn't have heated screens for the UK market, but this one will fit as will the later 2 connection version. my 3 connector version is [ use the hand written part number CMB000410 at the bottom of photo, taken off my screen when it was fitted] Quote Link to comment Share on other sites More sharing options...
rob90 Posted November 17, 2007 Share Posted November 17, 2007 Thanks Western much apreciated, Got all the wirring in place today, relay switch and light on the instrument panel, im kind of edging my bets on a two pole screen turning up from RAC windscreens on monday, If I get a 3 pole screen then I will add another 30 amp relay and wirrring, just waiting for my timing relay to arive also Quote Link to comment Share on other sites More sharing options...
western Posted November 17, 2007 Share Posted November 17, 2007 happy to help, if you end up with the 3 connection screen, the centre terminal is the earth. Quote Link to comment Share on other sites More sharing options...
jimstrong Posted November 18, 2007 Share Posted November 18, 2007 Hi,Im about to have a heated window fitted through my insurance and woul like to have the wiring in place before they came to do the job could some one confirm if the wiring connects to the screen at the bottom/top and drivers or passenger side? thanks rob Hope this went well for you. Could I ask a supplementary question? :- One side of my factory fitted heated windscreen on my 1997 Discovery suddenly stopped working last week. I think it was after I'd recharged the battery (I removed it from the car to charge). I'm not a great electrician, but am I right in assuming that only one fuse drives the unit and that therefore the problem is likely to be in the wiring to that side of the screen? Thanks a lot Jim Strong Quote Link to comment Share on other sites More sharing options...
rob90 Posted November 19, 2007 Share Posted November 19, 2007 Well new screnn was fitted to day I ended up with a 3 pole screen I guess thats better I dont know but its in did a bit of re-wirring and its all good now just need a freeze Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 19, 2007 Share Posted November 19, 2007 If you have two elements and a common ground connector, rather than wire +/-/+ on the three terminals, if you ignore the centre GND and wire one end to + and one to - you will be running the elements in series, halving the current draw, halving the power and doubling the warmup but potentially avoiding damage if no timer is fitted as the elements will be working at half power. Probably pointless but it would at least work without extra wiring/timers. Quote Link to comment Share on other sites More sharing options...
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