Scotty: My wife has a 2008 Mazda Miata with 87,500 miles, the 5-speed manual transmission, and the base A/C controls (i.e., manual fan speed adjustment, not thermostatic controls). Yesterday, she had the HVAC fan on medium with the A/C off. Started hearing loud noises around/behind the glove box so she turned the fan off. But, rather than turn off, the fan started blowing out full blast. Now -- A/C off or on, heater off or on, fan off or on at any speed -- the fan just runs on high all the time. With the car off, I removed the "fan" fuse and the "A/C" fuse -- no change. But, when I removed the 30 amp "heater" fuse and turned the car back on, the fan did not come on.
I've read that a bad fan relay on some Fords caused HVAC fans to run on high whenever they fan is on--understandable--but why would pulling the "heater" fuse stop the fan? Does the fan run on that "heater" circuit and the constant running issue is the switch/motor/relay, perhaps? I've got no idea where to start looking under the hood/dash of a car that my big old hands barely fit into in the first place.
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Thanks!
Hi, did you ever find out the cause an fix? Sadly, exact same thing started on my NC1 last night :/
the relay got stuck on. Change it.
Probably a bad heater blower resistor -
Thanks! I'll give that a try!
Hi, did you ever find out the cause an fix? Sadly, exact same thing started on my NC1 last night :/
It's most likely a stuck relay. If changing it doesn't help then you're better off posting a new question and posting all the details in the instructions. Thanks.