Mazda MX-5 Mk1 1997 - Heated rear window wiring

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Tue 4 Oct 2011 23:17
Mazda MX-5 Mk1 1997 - Heated rear window wiring - mikem
Hi all - can anyone give me a steer on connecting a heated rear screen in my son's MX-5, please as, thanks to some knife-wielding idiot, he's had to have a new hood fitted and has gone for a glass HRW rather than the plastic version.

I'm OK with the dashboard end as that appears to be just a case of plugging a new switch into the appropriate socket that sits behind one of the blanking plates. However I have a choice of 4 existing sockets towards the rear of the car, plus 2 narrow sockets at the ends heater element on the new screen.

In addition to the dash switch, I believe I'll need a 30A relay and a fuse block but I'm not sure where these will plug into. I guess it would become obvious which goes where if I were to buy Mazda items but I'd like to save a few quid and use Halfords ones if poss but, because I'm not sure which connector(s) to use, I don't know which relay / fuse block to go for, i.e. 4-pin, 5-pin, etc. I'm also wondering what rating of cable I'll need for the job.

There's an existing female connector just behind the passenger seatbelt post, then there are 2 'spare' connectors by the battery in the boot; one white/opaque with wiring of 1-2 mm thickness attached and a black one with approx 4 mm thick wiring, presumably carrying a heavier current. I believe one of these two would be used when an electric aerial is fitted, however this car has a manual 'screw-in' aerial. Finally, there's a further black 'spare' connector just behind the carpet in the boot, close to the number plate.

Excuse the lengthy post - I'm sure this is an easy job once I know which of the car's connectors come into play, and would like the satisfaction of doing it myself if I can.

Many thanks
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Fri 7 Oct 2011 12:27
Mazda MX-5 Mk1 1997 - Heated rear window wiring - Phil WAWA

Hi, I'm no expert as I'm having trouble with my HRW too.

What I do know is that if you look in the boot, on the right hand side near the battery, you will see some wires and what appears to a black cap on the end (near the aerial). From memory the black cap has 'DEFOG and 'ANTENNA' printed on it. If you unclip it you should see the holders for 2 x 10A fuse. There needs to be a fuse in there for the DEFOG.

Also in the boot, behind the number plate, there is a small (4 pin?) socket that will need a relay fitted to it - this needs to be a 'LA10' - usually a few on ebay etc @£5.

You already know that you need the switch on the dash - should connect to a blue 4 pin connector.

Now that's where my knowledge ends. There are a few articles on the www to help with the connector behind the passeger seat, though I have not had any success myself. I have the exact same problem. I used to be able to swith the switch on and got an orange light on the dash to confirm the hrw was on. After fiddling with the wires that light no longer illuminates. I have replaced the fuse and relay, but still no joy, so any advice will be gratefully received.

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Fri 7 Oct 2011 21:29
Mazda MX-5 Mk1 1997 - Heated rear window wiring - mikem

Many thanks Phil - that certainly confirms one or two points and moves me on a few steps. I'll report back in due course, although it might be a couple of weeks or so. If my endeavours give me any ideas to help solve your own problem, I'll get back to you asap.

Any more info from other 'readers' would be most welcome.

Regards

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Sat 8 Oct 2011 10:27
Mazda MX-5 Mk1 1997 - Heated rear window wiring - ohsoslow

Have you tried asking on the MX-5 Owner's club site? Someone will likely be able to help over there.

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Mon 10 Oct 2011 21:34
Mazda MX-5 Mk1 1997 - Heated rear window wiring - mikem

Have you tried asking on the MX-5 Owner's club site? Someone will likely be able to help over there.

No, I haven't as yet - obvious when you think about it! Thanks for the suggestion.

Regards

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Mon 10 Oct 2011 21:48
Mazda MX-5 Mk1 1997 - Heated rear window wiring - mikem

Phil - I've discovered that there should be another fuse (10A mini-blade) for the defog, in the fuse board right up under the dash on the right-hand side wall (it's mentioned in the owner's handbook). Fuse bay No. 20 if I remember correctly. Might be worth checking out. Good luck.

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If you cover no more than 100 miles per day and have easy access to a charging point at home or work, then an EV is ideal for you.

Is an electric car right for me?