Would a stone chip stop the heated windscreen working?

[Big Bad Baz]

It's been a bit condensation-y one the way to work recently and it appears that my heated screen has stopped heating.

 

Checked fuses and there was one blown 10a one; not sure if this was the fuse for the screen, but changed it anyway. Circuit-tested the screen connectors and there's definitely 12v getting to the right place but the screen still doesn't seem to be working.

 

Then, whilst giving Napoleon a clean yesterday, I noticed this:

 

http://farm4.staticflickr.com/3744/12153902113_8dfdc8b6b6_c.jpg

 

It looks like the stone has hit right between two of the heating elements, but I was wondering if the crack behind the point of impact has somehow broken an element - and if (like the old rear screen demisters) if damage to one element would stop the whole thing working?

[7 wonders of the world]

check the continuity on the screen element with a multi meter

[Chris Cardwell]

The other elements will continue working

[john aston]

No. I have several on my screen and a little crack(quiet ) . It still demists properly .Patina innit.

[7TOM]

Hi I suspect the damage would not render the whole screen inoperative.Continuity is not the best check as it would come up ok if only one element was working check the live and earth when circuit is under load ( screen on) you should have battery voltage one side and less than 0.3 volts on the earth side.

[SLR No.77]

My screen has a 6" crack along the bottom edge, perpendicular to the element wires. it still works fine

 

Stu.

[tbird]

Quoting 7TOM: 

Hi I suspect the damage would not render the whole screen inoperative.Continuity is not the best check as it would come up ok if only one element was working check the live and earth when circuit is under load ( screen on) you should have battery voltage one side and less than 0.3 volts on the earth side.

 

and you will have whether heat elements are OC or not, its unlikely the chip will have damaged any elements but at worst it would only be 2 of them so the rest would work, certainly check for continuity, if you have continuity ( some low resistance probably less thn 5 ohms) if OK, check voltage on both screeen contacts, should be 12v and zero, no 12 v = problem with feed, 12v on both sides = problem with earth, 12v on one side and 0v on other side = you lying to us and its working 😬

 

Tim