Need help w/ 2010 Honda Civic electrical quirks.

Discussion in 'Civic' started by k_a4_denw, Jun 3, 2026.

  1. k_a4_denw

    k_a4_denw New Member

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    I'm likely going to be buying a 2010 Honda Civic from my teacher for $300, and the reason he's letting it go is mainly because of these weird electrical issues he's having, which I wanna get an idea about before diving in.


    He said when he bought the car 8 years ago, the car had a parasitic draw, which caused the battery to die, so he pulled a fuse, which he said "Without that fuse, a lot of things don't work including the radio, using the buttons on my car key to unlock/lock the door, and probably some other things." I have a suspicion that the fuse was #27 in the cabin fuse box (the HAC or something?), because that fuse is still gone.


    He said recently the car had some cooling issues or something (I suspect either the thermostat or radiator, from what he said), it overheated once, and he took it to a shop to get it fixed. When he got the car back, the big electrical issues began. Basically, the car alarm goes off as soon as any door is opened or when the key is turned. He's unable to stop it with the key or any button and has to wait for it to cycle to stop, so even after the car starts and drives, it continues. When I went to see it, the second the car got power the alarm went off (I think the door was open). The car runs and drives fine, but the battery dies now and has to be jumped every time. Also, now the passenger window has stopped working, apparently.


    He suspected the car had an aftermarket alarm installed, and when I went to briefly check the car out in person, I saw a bunch of non-stock wiring in the cabin fuse box relay unit assembly. He's been removing fuse #12 in the engine bay fuse box to stop the horn when the alarm goes off, but he's unable to drive the car with that fuse removed (it starts but won't go into drive).


    I'm guessing the major issues the car's having now have to do with whatever the mechanics did when fixing the cooling issue. Could it be a ground or something? I'm hoping it's something minor like that because the alarm started freaking out after he took it to the shop. I'm also wondering if any of those jobs involve removing anything having to do with the electrics.


    And either way, I'd probably try to remove whatever aftermarket system's been installed (unless it's possibly salvageable), so help with that would be great. I noticed the wires that plug into the Cabin Fuse Box Relay Unit Assembly, directly under the top 3 fuses were spliced into and messed with. What are those wires for?


    The thing is, this is my first "project car" I guess. I have a 2012 Audi A4 which is my first car, and I've done some stuff like replacing fuel injectors and installing coilovers, but obviously nothing electrical. So I really am not too familiar with the electrical and wiring aspects of cars. But I'm hoping this is relatively simple, especially with this being a civic.


    When I checked out the car, I was only able to get some quick photos of under the dash, and I saw that the wires going into the connectors directly under the top 3 relays were messed with and spliced into. I also saw some unplugged wires lying on the ground, which had labels on them (I didn't get a chance to look closer), which looked like they might possibly be part of an aftermarket kit, but again, I'm not too familiar with this stuff.


    I attached the photos I took of under the dash. If anyone can make sense of this, I'd greatly appreciate it.
    IMG_9648.jpg
    IMG_9646.jpg
    You can see next to the kick panel there are random wires lying disconnected, some with labels too. Wondering if that might be part of an aftermarket kit?
    IMG_9649.jpg
    IMG_9636.jpg
    Definetly spliced into the wires going into the connector right under the relays, what are they for?
    IMG_9668.jpg
    Noticed this fuse was gone, maybe the one he pulled when he got the car?



    I just need some guidance on how bad it is, what the issues might be caused by, and if it's something I can do as someone with really no experience
     
    k_a4_denw, Jun 3, 2026
    #1
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