Author Topic: Rear demister only half working - please help ? (Read 6713 times)

guest7354 · « **on:** January 15, 2018, 06:28:17 PM »

Hi , I am new on here so apologies as I'm not sure how to navigate myself around . I have a Honda Jazz 07 plate and today I noticed that only the middle section of my rear window demister works . The top and bottom stayed fogged up . Obviously as part of it is working then it can't be a fuse but I'm a bit stumped as to what to look for . Has anyone else had a problem like this or has any idea of how to resolve the problem ? Thank you 😊

MikeG1944 · « **Reply #1 on:** January 15, 2018, 06:42:52 PM »

A demister is made up of lines of conductive 'paint' which when current is passed through it heats up. If they get damaged and there is no continuity due to a minute break along the line then the current cannot pass through and heat it up. There was a fix that came out many years ago which was a small bottle of conductive paint which bridged the gap and got it working again. I tried it once and it worked. Cheaper than a new rear screen.

Think this may be the one...
https://www.ebay.co.uk/itm/ATG-Windscreen-Heating-Fixing-Defective-Rear-Window-Heating-DIY-Repair-Kit/282780934482?hash=item41d70ea152:g:mp8AAOSwdjdaO9tV

Mike.

Jocko · « **Reply #2 on:** January 15, 2018, 07:23:22 PM »

Yes, the two vertical strips are the positive and negative bars and the individual horizontal strips are the heater elements. it only takes one small break in a strip to render it open circuit, but be aware, if the strips have been damaged by over enthusiastic cleaning, there could be more than one break to a strip.

MikeG1944 · « **Reply #3 on:** January 16, 2018, 09:09:03 AM »

Also be careful of the spade connectors where they fit on the glass, if these are treated roughly they will become intermittent or fail.

Best to avoid cleaning the inside of rear windows unless it's really necessary and then treat it like your expensive Porcelain figurine.

sparky Paul · « **Reply #4 on:** January 16, 2018, 09:18:02 AM »

If you have been carrying any large boxes or similar in the boot, you can scratch the demister element quite easily if it rubs against the glass.

+1 for the conductive paint, if you can locate the breaks in the circuit, a spot on each one may well fix the problem. I've repaired a few rear demisters like this.