Estate rear screen heater problem

[Kiwi]

On my 2000 model Hdi estate the rear screen heater is very slow to heat up, just to demist, by the time the screen was cleared (outside temp, -7C) the screen was still cold to touch. Last year I checked feed voltage and resistance on the ground side, (all values were OK) as it seemed slow then but now there has been a sudden drop off in heat output with the cold weather
The timer is working (indicator light stays on for what seems to be usual time ) Will recheck circuits as soon as I reclaim my meter.

Are there any relays, sensors, etc than can cause this problem ?
Can the heating element have surface corrosion that can affect its performance ?
Is there a resistance value for the element itself ?
If a 12v supply was hooked up direct to the screen element , would that possibly indicate where the problem is ?
And lastly, how do you remove the plastic retainers for the inner panel without destroying them ?

I'd appreciate very much any suggestions. Thank you.

[steve_earwig]

I guess there's a timer relay, somewhere... Check it for 12 volts, also watch for dead zones where the elements have burned out. I've never felt one get warm, they're just not that powerful.

Which inner panel do you mean? If you mean the one on the tailgate then there's no foolproof way without destroying them, they're cheap and they're nothing special either so you should be able to pick some up from a factor's.

[FarmerPug]

with this cold weather you just cant expect it to demist the window instantly.

[Gary406]

my rear window is clear from a thin layer of ice within 3 minutes

[Gary406]

but ye i agree with executive , in the really cold mornings its bound to take 5-10 minutes with a think layer of ice on it,

i dont thing its made to remove layers of ice its only there to keep the window from steaming up on a rainy day with 5 people in the car

[FarmerPug]

If your in a rush to remove ice put a blanket or old carpet over the car:

[Kiwi]

Thanks for the replies. I agree with Gary 406 though, I was in France during a winter with the car outside in -14 C and it was melting the ice by the time I had finished scraping the other windows. I was surprised how warm the screen was to the touch after just few minutes.

[FarmerPug]

It sure does melt the ice all right, and i suppose it does feel warm, time for a joke:

Why does skodas have heated rear windscreens?

To keep the hands warm for the people pushing it.
dont go saying skodas are good cars now, this is about the old skodas before vw owned them, and really skoda cant take the credit now because all they are doing is bolting together bits of vw mechanicals into a body they designed under the supervision of vw. So its still ok for skoda jokes

[mjb]

Why does skodas have heated rear windscreens?

To give the car's occupants something interesting to look at... "ooh look, it curves round a bit!"

dont go saying skodas are good cars now, this is about the new skodas since vw bought them, and really skoda cant take the credit now because all they are doing is bolting together the blandest bits of vw mechanicals into a bland body they designed under the supervision of vw workers' children on work experience. So its still ok for skoda jokes

[FarmerPug]

yipee, and can we do seat jokes because they are crap also, i know they are marmite cars you either love the look of them new seats or absolutley dispise the sight of them, well im the latter option.

[Doggy]

Straying perilously close to the original thread for once, Doggy suggested the loom around the door hinge is a possible culprit as he's had to pull new cables into his bro's D8 to get the rear wiper and number plate lights working again.

Sod of a job, but doable.

Right, enough of that....

A VW by any other name is just as boring

* takes cover *

[FarmerPug]

is vw the worlds biggest car manufacturer yet, it seems when a company is at that status they make drab cars, eg toyota, and GM

[Kiwi]

On my 2000 model Hdi estate the rear screen heater is very slow to heat up, just to demist, by the time the screen was cleared (outside temp, -7C) the screen was still cold to touch. Last year I checked feed voltage and resistance on the ground side, (all values were OK) as it seemed slow then but now there has been a sudden drop off in heat output with the cold weather
The timer is working (indicator light stays on for what seems to be usual time ) Will recheck circuits as soon as I reclaim my meter.

Are there any relays, sensors, etc than can cause this problem ?
Can the heating element have surface corrosion that can affect its performance ?
Is there a resistance value for the element itself ?
If a 12v supply was hooked up direct to the screen element , would that possibly indicate where the problem is ?


I'd appreciate very much any suggestions. Thank you.

Just bumping this up again, still can't find a remedy after following suggestions................. Still wondering about this ;
Are there any relays, sensors, etc than can cause this problem ?

Thanks

[steve_earwig]

Errr, did you do any measurements? 12 volts, continuity, anything like that?

[Kiwi]

Errr, did you do any measurements? 12 volts, continuity, anything like that?

Yes, continuity OK ( diode tester), resistance of screen heater 1 ohm, voltage across feed loom terminals with engine running , 14.5 v. I didn't " hotwire " it with 12v as I saw no reason after checking the feed voltage.

My next thought is to wipe a lemon slice over the inside of the element to remove the oxide.......? I do this to clean copper jewellery, etc.