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Hi Grant,

Thanks for the quick reply. I've checked all those fuses and all ok. Relay next or switch? 50/50 chance I guess.

Also my sunroof is sticking on opening- it does go but its sticking before it tilts and takes a few goes fore it to work. Any tips?

Cheers mate

Further to rear screen demist probz
Someone told me it might be a break in the wire itself on the screen. I've had a visual check and cant see a break - is there a way to test this?

If it were a break in the grid the indicator light would still work.

Can you hear the relay "click" when you turn the demister on? The ignition will need to be on to operate it.

Either way the next step will be to check for voltages at the relay.

btw - the sun roof - just clean the hell out of the rails. If it still sticks, clean them again. Its a pretty common problem and if its working electrically, it can't be much else.

Thanks Grant. I don't get a click at all. Where is the relay at? It's missing from the online manual so I cant get any info about it.

Took your advice n cleaned sunroof- perfect!

Took your advice n cleaned sunroof- perfect!

I'll look up where the relay is tomorrow and the wire colours, etc (gotta start another computer, etc, etc and its nearly midnight).

The defrost relay should be under the dash, above the drivers feet. The wire colours going to it should be:
BLACK / YELLOW (12V with ignition on)
YELLOW (switched ground)
BLACK / BLUE (12V to demister when the relay operates)
BLUE (Constant 12V)

Locate the relay and do the following:
1. Check for 12V on the BLUE wire
2. Turn on ignition and check for 12V on the BLACK / YELLOW wire
3. If those voltages are present, get somebody to press and hold the demister switch and check for 12V across the BLACK / YELLOW and YELLOW wires. If you have 12V across these the relay is no good.
4. If you don't get 12V across those 2 wires (but have 12V to the BLACK / YELLOW), touch a jumper wire from ground to the YELLOW wire and the relay should pull in.

Hope thats clear enough.

DOH!
I've had my head under the dash.. and I do get a click from the relay.. sorry about that Grant.. I guess I could'nt hear it with the engine running... Yes I'm a Galah!

So it's the switch? I've managed to get my hand under and feel the back of it. Do I need to dissamble much to get it out?

If its clicking it means the switch is ok! And the relay probably is too.

Have you actually changed the fuse in the engine bay? If not, you should to make sure its a good one. Do this first.

If that doesn't work, you'll need to check for 12V on the BLUE wire on the relay. If you have 12V, you'll need to press the switch to "on" and see if the BLACK / BLUE powers up.

Thanks for that Grant
Itis the relay after all- black/blue is very slightly burnt but still active so the relays stuffed. 22 quid from mazda!! Rip off! I'm gonna try to get a second hand one.

You can use virtually any relay. You may just need to cut off the plug and crimp spade luds on the cables.

! was thinking that myself.

The problem with that though is all the aftermarket ones have a different connection with the way the spades are so I'd have to chop the connector thats on it know and basically fudge it and then it wont sit nicely in the harness as it does now. Theres a severe lack of Mazda auto breakers here too...

Yes, you'd need to crimp spade lugs on so it wouldn't be a straight out unplug to swap it in the future. Cost versus aesthics and convenience.

my defrost dosent work at all so I checked the wires to the relay and the BLUE wire is not getting any voltage reading(regardless if the ignition is on or off).and the YELLOW to BLACK gets nothing when ignition is on.....I also looked at the relay and its perfect.
So do I have a wire that is screwy somewhere?

The switch is brand new, all fuses have been replaced so whats going on here? Thanks