Blower Motor Only Works KOEO
I should probably do some testing first as I have a few thoughts, but I’d figure I’d pick some brains. So my blower motor has been non operational for a few weeks but I’ve been fixing other issues and it was no longer on my mind. Off topic, but today my water pump grenaded itself and I went to go check the water temp without turning the engine on after a drive, and I noticed my blower motor turned on. I then turned the engine on, blower motor turns back off again. All speed positions work fine with engine off, rpm’s hold steady, works great. Turn the engine on, absolutely nothing. Cannot be a heat soak issue as when I did all of this the engine was well above operating temp and blower motor still doesn’t work on cold starts.
Question/Idea #1: Does the e30 have a specific “Engine on” circuit that is separate from the “run” position on the key switch? I know newer CAN bus vehicles have this but definitely not something I’d expect from an E30, if this was the case, I’d say it points towards ignition switch.
Idea #2: Maybe a weak connection that barely works on the ≈12v engine off but can’t handle 13.5v+ when alternator kicks on? Again, very doubtful with this huge longshot as the chances of my symptoms being repeatable over and over make that very improbable
Idea #3: Possibly the famed resistor. This one i also doubt as it didn’t have any of the tell tale symptoms of a bad resistor, all of the blower speeds worked when it failed, and still do work now when engine is off.
Idea #4: Maybe the blower motor itself? Not really any reasons for or against this one but still doesn’t make a whole lot of sense to me, if it is I’ll have to pull the motor apart to see if I can make sense of that.
Idea #5: Last one of my thoughts as of now is the relay is acting up. I haven’t had many relays go bad, but when they have, at least in my experience, they always make things act funny instead of just giving out entirely.
I’m sure there’s more possibilities it could be, maybe even some real obvious ones I’m looking over but I guess I won’t truly know until I tear it apart here soon, I’ll definitely chase it down until I find it but I’d say my main reasoning for the thread is I haven’t heard of this issue yet or seen anything about it so I figured it’d be nice for someone else to find this thread if they have the same issue in the future after it’s solved. Any thoughts are appreciated!
Question/Idea #1: Does the e30 have a specific “Engine on” circuit that is separate from the “run” position on the key switch? I know newer CAN bus vehicles have this but definitely not something I’d expect from an E30, if this was the case, I’d say it points towards ignition switch.
Idea #2: Maybe a weak connection that barely works on the ≈12v engine off but can’t handle 13.5v+ when alternator kicks on? Again, very doubtful with this huge longshot as the chances of my symptoms being repeatable over and over make that very improbable
Idea #3: Possibly the famed resistor. This one i also doubt as it didn’t have any of the tell tale symptoms of a bad resistor, all of the blower speeds worked when it failed, and still do work now when engine is off.
Idea #4: Maybe the blower motor itself? Not really any reasons for or against this one but still doesn’t make a whole lot of sense to me, if it is I’ll have to pull the motor apart to see if I can make sense of that.
Idea #5: Last one of my thoughts as of now is the relay is acting up. I haven’t had many relays go bad, but when they have, at least in my experience, they always make things act funny instead of just giving out entirely.
I’m sure there’s more possibilities it could be, maybe even some real obvious ones I’m looking over but I guess I won’t truly know until I tear it apart here soon, I’ll definitely chase it down until I find it but I’d say my main reasoning for the thread is I haven’t heard of this issue yet or seen anything about it so I figured it’d be nice for someone else to find this thread if they have the same issue in the future after it’s solved. Any thoughts are appreciated!
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