Any thoughts on what would cause the 7.5 amp Backup fuse to keep blowing? My girlfriend pulled in the driveway and everything was fine. Got back in the car later and the radio and clock are dead. I traced it to the 7.5 amp under hood 'backup' fuse. I go to put another fuse in, and it blows... bad... as in blue flash and melted fuse. I try a 15amp (I know, I know) and it blows just the same. Any thoughts on what this may be? It blows with the clock, lighter, and radio completely removed from the car.

We're getting over an ice storm here. Any chance there is water in a plug somewhere that I can track down easily? Any other ideas are appreciated. All other fuses are fine.

EDIT: I didn't realize this was also the ECU fuse. I'm a 4th generation guy. I'll do some more archive searching on ecu fuse, but suggestions are still appreciated... especially anyone that knows where that wire is located that may have gotten water/ice in it.



Modified by therealciviczc at 2:35 AM 12/30/2004

 

is it blown right after you replace it? does the underhood fuses panel got wet? do you have leak near the ecu? did you install any electronic equiptments lately?

 

Nothing installed. The car is stock. The underhood box looks dry as a bone as does the ECU area from what I can tell. The fuse pops instantly. I tried disconnecting the battery, putting the fuse in and reconnecting, and it blows the second I hook the battery back up.

 

Answering my own question for future searches since I found a lot of others with this same basic problem and am sure there will be more to come.

Symptom was dim clock, no clock memory, no radio (or radio memory depending on radio type).

Problem was 7.5amp fuse blowing under the hood.

Cause was a worn wire grounding.

Found by...

1). Remove all the related accessories that run off of this fuse. I removed the radio (still blew fuse), the clock (still blew fuse), and ECU (still blew fuse).

I now know it is in the wiring and not in the devices that run on that wiring.

2). Unplug the plugs under the hood. First I unplugged the one on the drivers side (not sure if that wire even goes through there) and then the ones up near the battery and fuse box. Still blew fuses.

I now know my problem is somewhere between the battery and the first set of plugs. I took the battery out and immeadiately noticed I had pinched part of a wire loom between the battery tray and the structure of the shock tower. I hadn't had the tray out in many years, so I was surprised. I took the tray out, and due to the ice storm and rough chunks of ice on the road, it had finally worn through the wire. I fixed the wire and everything was fine.

The wire loom wants to move itself to this spot when the battery tray is removed, so I wouldn't be surprised if this has happened to other people. Its sort of a shitty design.

Hopefully this helps someone in the future. Just keep tracing back that wire and removing stuff to make toward the source to isolate the problem. You can also disconnect everything and start working your way out and isolate the problem by seeing what causes the fuse to blow.

 

Damn, way to figure it out yourself! I'm quite impressed.

I know sometimes some very unrelated things can run off of a common fuse. Hell, when the interior light fuse on a Civic goes, you can't run your windsheild wipers on the lowest setting.

 

Bringing this thread back from the grave. What plugs are being unplugged? I have this problem. My stock radio is gone and the wires were cut (bought it like that -_-). Could it be because of the cut wires?

 

Check whether the same constant power wire to the radio, clock, or heater control panel is shorting out.

 

I'm an idiot when it comes to wiring. How do I go about doing that ^? Where would they be located?

 

What car do you have?

 

Chances are that with the harness being cut you also have a grounding issue going on somewhere.

 

94 civic 4dr ex
Where to check?

 

Right there at the cut wires for a start.

 

Could always use a harbor freight fuse They don't blow.

 

Among the cut wires behind the radio, look for two cut Wht/Blu wires for the clock and radio. One of them likely has exposed metal and is shorting out.