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2004 Mazda Mazda3 Question: Rear defrost not working



rmaccrea, Webster, TX, February 11, 2011, 17:52

I bought a used Mazda 3. My rear defroster isn't working. The light doesn't come on in the dash either. I checked the fuse and even switched it with another fuse in the box. Nothing. What else should I look at?

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  • Answer #1

    February 11, 2011, 19:12

    Sorry, I don't have a wiring diagram for the rear defroster. I'm sure there's a relay controlling the circuit, FYI, probably controlled by the switch. Find the relay in your owner's manual if you still have it. If that's OK, I'd check for power and ground at the switch and the relay to work on determining where the failure is. You could find an auto electric shop or a Mazda specialist to help you if you're not good at electrical systems.
    Here's a directory link for you:

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    rmaccrea, February 14, 2011, 09:41

    Thanks! I didn't think to check if there was a relay. I think it might be a problem with the switch though. The A/C switch is pretty touchy and it will switch off randomly. If I jiggle the fan speed knob it comes back on. Weird. I think I'll end up replacing the whole switch assembly if it's not the relay.

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