by Alan D. » Mon May 13, 2013 10:17 pm
Tips for fitting a heated front screen:
Just a note to mention the 3 golden rules when fitting the new Mk4 heated windscreen. Rick, did say that any decent fitter would do this in any case but just to be sure:
1, Paint 3 layers of etch primer (glass) around the edge of the screen. This is to stop water from ever seeping in between the layers of glass. On a normal screen this results in a milky discoloration but no harm. On a heated screen the elements corrode and it stops working.
2. As you fit the screen, align the wires upwards into the field of vision, put glue between the wires and the glass within the masked off area, fit the screen to the shell and then bend the wires back down to the dash for their electrical connection. This ensures that there are no cavities in the glue area around the wires allowing for air or water leaks.
3. Each screen has 2 separate heating elements, 1 on the left and 1 on the right, hence 2 pairs of wires. Each element requires a +12 volt supply and an earth. It doesn't matter which of the wires is which. Rick has a example wiring diagram on his website. When designing your electrical circuit, do not connect it directly to the battery, use a switch. Rick also recommended including a tell-tale lamp to say that the screen was on, taking the supply from the switched ignition so that it doesn't flatten your battery by mistake. It was suggested a better solution might be a timed switch so that the screen only stays on for a minute or so, they draw a lot of current but can work very quickly to demist a screen.
One screen left.
Alan