johnjapan Posted November 20, 2019 Share Posted November 20, 2019 (edited) Since Friday my 2006 Subaru Legacy has been becoming almost completely electrically dead, before eventually starting working again. It started with my dashcam and FM transmitter (both connected to the 12v cigarette lighter socket via a USB adapter) switching off while I was driving. I pulled over to check, and when I tried to switch the car on again nothing happened. . Fast forward to today, I've replaced the battery, and learned a little more about the problem: - It doesn't seem to have anything to do with what's plugged into the 12v socket - I've removed its fuse. This didn't seem likely anyway since the circuit is only live if the engine's on. - It doesn't seem to be a ground fault - I've checked the voltage between the engine body and exposed metal on the car. It's 0 volts. - Things that don't work: remote locking, central locking (via switch inside), interior lights, instrument panel doesn't turn on when the key is moved to the on position or the door is open, door chime. - Things that do work: hazard/warning lights (and corresponding indicator lights on the instrument panel), parking lights, horn, driver seat motor. - It's not a low battery as it when it eventually recovers, it starts by itself. Also, jump starting doesn't make a difference when this happens. Battery terminals are tight, battery is new, alternator was checked by a shop and it's OK. Is this likely to be the main relay, or something else? If the relay, then am I correct in thinking it's behind the glovebox? Thanks! Edited November 20, 2019 by johnjapan Link to comment Share on other sites More sharing options...
johnjapan Posted November 20, 2019 Author Share Posted November 20, 2019 OK, so it seems like the 120a main fuse has blown. So I'll get that replaced, though now my thoughts are onto why it has blown. Link to comment Share on other sites More sharing options...
Max Capacity Posted November 20, 2019 Share Posted November 20, 2019 Main fuse, so where does it get it's incoming power from ? here's the service manual. http://people.csail.mit.edu/ilh/vacation/ 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
johnjapan Posted November 21, 2019 Author Share Posted November 21, 2019 here's the service manual. Thank you so much! That's super helpful. So far I've only had wiring diagrams (which is all I need in this case) but this has so much more. Before this issue presented I'd been having issues with the secondary air system (I'm actually booked in with Subaru to get it fixed), which seems to run directly off the circuit from the main fuse (MB-33, MB-34). I have an inkling that these two problems are related. I'll have a look down this route and see where it takes me. Thanks again! Link to comment Share on other sites More sharing options...
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