I hate cars. They’re just giant expensive pieces of cost-engineered crap that cause horrible anxiety. Apparently, the service manuals for them pile confusion on top of that as well.
I don’t know WHO this diagram was designed for, but it was clearly not to be seen by human eyes and minds. OUCH.
From the factory service manual:
Ow. My brain. I mean— this IS a schematic, but… ow.
I redrew it to make it easier to understand and follow. The scanner in my office doesn’t understand the orange I highlighted the wires that should be energized off +12V ignition switched and turned it kinda beige-ish. Whatever.
I omitted the “Through Joint Connector” points shown here. I have no idea what those physically are – my best guess, being that I didn’t see a bunch of connectors in the circuit, is that they mean those are internally connected on the ECM harness plugs or in the fuse/relay holders.
Fuse F22 is a horrible mystery. Check it for yourself – the factory schematic suggests that the ONLY thing it powers is the “Sub Fan” relay coil, not the actual fans themselves. Why? Actually WHY ANY OF THIS???
In general I have a love/hate relationship with any cooling fan control system that incorporates a low fan speed for pretty much no good reason, and by that, I mean, I love to hate every single one of them. I’d rather hear a single loud fan cycling on and off than knowing that the whole control system is a ball of spaghetti wrapped around a meatball of ticking time bomb complexity. I also love that when I was trying to figure out how this works (the manual doesn’t really explain it) I found that there’s a reasonably useless possible state for the system of running one of the two fans.
I’m having an issue with one of the relays causing one of the fans not to spin. Specifically, it’s the “main” fan on the driver side, suggesting an issue with Main Fan Relay 2, which I was able to get the cover off of and look around inside… it looks like it’s gotten hot and both contacts looked pretty raunchy. It is not the logic state that you’d get to if the ECM were to ground pin B12 and not B11, which would cause the main fan to run only, at high speed.
So here’s the adventure so far—-
I’ve been through one radiator fan which might not have even been bad in the first place, though it spins kinda rough and probably needed to be changed even if it WAS functioning (that being the case, it may have been drawing too much current and pitting the relays).
Pictures from this silly adventure ahead (let’s keep this post from making the main page a kilometer long!)
Read more “2014 Subaru Forester Fan Relay Diagram For The Rest Of Us”