Just bought an 2001 Honda Accord v6 coupe, threw in a new battery, sparks, starter, alternator, and a few much needed fuses. Things were great after I finally got the alternator in except that it keeps blowing the 7.5A instrument back light fuse on the drivers side panel #9. I've spent hours searching for bad wires with no luck. I double checked the ground wire on the alternator and even took it out completely and reinstalled it just to be sure everything was set right. Yet when I drop the new fuse in the dash comes to life for roughly 10 seconds before it blows the fuse. I've been losing my mind trying to figure out whats causing it to happen. It has to be a short or bad ground but I'm not sure where else to check at this point. The negative battery terminal doesn't have the best hold on the wires so I do still need to splice that, which I'm doing today but other than that I don't know what else to check at this point. I've gone through with a multimeter to everything I can think of and spent hours sifting through dozens of forums with no luck. Any advice would be greatly appreciated!!! Skill level is intermediate, though this is my first Honda, I've owned and rebuilt an Pontiac G6, An 88 Camry, and an 03 Explorer with little to no issues. This has me throwing tools like never before!

 

Is the 10 seconds consistent for the fuse to blow, or do you do something like hit the brake pedal to shift that will blow the fuse? The timing may help narrow down the issue.

Fuse #9 is labeled instrument backup light fuse, but protects several other circuits.

Back-up lights, brake failure sensor, clock, DRL indicator (if in Canada), Gauge assembly, mutiplex control unit both driver's and passenger, shift lock solenoid, trailer lighting connector.

As shorted component or wire can cause the fuse to blow. The fuse protects a yellow wire powering each component. My suggestion is to buy a bunch of 7.5 amp fuses and disconnect all these components, then see if the fuse still blows. Also inspect the wiring nearby for any obvious signs of damage/overheating, corroded pins, or electrical repairs. Plug in one component at a time, then see which component blows the fuse.

I highly recommend getting a shop manual for your car. You can get a pdf for your car from automanualscource.com for ~$22 and it is worth the investment for DIY work.

Depending on what you find, a u-pull-it junkyard my be your best option to find inexpensive replacement parts.

 

So I decided to try another fuse to get a better time reference. It blows around 3 seconds into the vehicle being on. Made sure I wasn't touching the pedals. The only other thing I forgot to mention was that the vehicle is locked in park even with the vehicle running. It turns over and idles fine It just continues to throw this one fuse.

 

So the shift lock solenoid is holding the shifter into place?

 

If that's what causes it 😐 honestly not sure, I'm part brain dead when it comes to electrical.

 

I looked at the shop manual. The solenoid locks the shift lever in place when it has power and ground. The fuse blowing is causing the shifter to stay locked in place.

My best advice is to unplug all items that I listed before. Then plug them in one at a time to hopefully narrow down the faulty component blowing the fuse. The grounds/alternator are not on this circuit, so I wouldn't worry about them.

This type of issue takes patience to figure out. Hopefully unplugging all of these components will prevent the fuse from blowing, then you should be able to identify the culprit.

 

If this happened after replacement of the alternator, unplug the electrical connector at the alternator, then see if driver's side Fuse No. 9 still blows.

 

I'll give that a shot! Will update soon

 

Still blows the fuse 😭

 

This is the circuit diagram for driver's fuse no.9.