I’ve been having the same issue with my car but my problem is the #21 back up fuse under the hood keeps blowing which I know is a short somewhere in the wiring. It’s giving me all the same issues as you were describing but it’s also making it so my OBD2 port dosent draw any power so if I get an engine light I won’t be able to scan any codes. I know this is a few years after this initial thread but does anyone have any tips on how to find the short circuit that keeps blowing my fuse?

 

I bought a box of new 10A fuses and when I put it into the fuse slot it blows everytime instantly

 

I moved your posts to a new thread. One thread with different fuse issues can get confusing.

Is your accord a 4-cy or V6? When the backup fuse blows, what else is not working in the car?

Any recent work done on your car?

My newest shop manual goes to the 2011 accord, so the 2011 backup fuse might protect different components.

 

hello thank you for replying. My accord is a 4 Cylinder, and for the past year I’ve been having issues where my car gets no power whatsoever if my key is not in the ignition, like no lights work or anything but once I put the key in everything works like normal. I’ve also noticed it is causing my OBD2 port to draw no power so I can’t use any scanners to check codes on my car. I do have a intermittent issue with my high pressure fuel pump so sometimes that makes my engine light come on so I at least know why my engine lights on, but I think this fuse blowing is causing this idk what else it could be

 

I also have one of those Haynes repair manuals for my car and I see in the back there’s a bunch of diagrams but I’m not sure how to read them correctly for this specific fuse that’s blowing, the #21 backup fuse near the engine

 

Most likely one of the modules that backup fuse protects has failed and is causing the dead short to ground and blowing the fuse. The hard part is to figure out what modules are protected by that fuse. Once you have the modules on that circuit, then you unplug one at a time and see if it blows the fuse. When the fuse doesn't blow, then you found your culprit. Or you can try unplugging as many as possible, then plug in one at a time to see which blows the fuse.

In your Haynes manual, does it have a section for power distribution? If you can find that section, and post a picture of the diagram or table listing the items, we might be able to help.

If your 2013 accord is similar to the 2010-11 accord, there are a bunch of items on that circuit.

Does your car have an aftermarket alarm system installed or dealership alarm system installed as an accessory?

 

Hello yes I do have a aftermarket alarm system that Honda installed before I got the car, it’s called a Dfence alarm system and it’s like wired in underneath my steering wheel and I only had the subscription for like a year which I’ve had the car for over 3 years now

 

And in the haynes manual I didn’t find anything for power distribution but in the end of the book it has like 20 pages of the electrical system throughout the car, would it probably be in one of those potentially? I’ll add snips of them into the thread

 

 

Alarm systems that fail can cause a lot of strange electrical problems in a car. Can you get a model number for that system? It should be on the control unit. I want to look up how it is wired.

Those wiring diagrams are helpful. 3 of the pictures did not show fuse 21, but the rest did. If you look on the top left area of each wiring diagram, there will be a box labeled underhood fuse box. Fuse 21 is labeled A-21 and is a 10amp fuse on a white wire. You can trace the wire along to wiring diagram and find out where it ends. For example, on a few of the diagrams, the wht wire ends at the MICU, so the MICU is protected by that fuse.

Lets start with the alarm system first, then work backwards to the OEM components.