CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Electrical problem with my 2004 Honda Civic DX

I have a 2004 Honda Civic DX 5 speed.

I’m having an issue with my rear park lights, and my front side markers. Fuse number 2, (15amp) blows every time I switch on my park lights. I have tried tracing all wires from the rear tail lights to the conjunction by the passenger rear door, found nothing all wires are good. I have tried disconnecting all taillights and headlights and tried switching on the park lights and the fuse still blows. I’ve probably gone through about 10 fuses while trying a bunch of different techniques to track down the problem.

Does anyone have any suggestions?

How exactly did you determine that all the wires are good? To me if you disconnected all the bulbs and it’s still blowing that suggests a wire is grounding out somewhere.

4 Likes

Gotta back up @shadowfax here. There is a hot wire finding its way to ground somewhere. You just haven’t found it yet. Finding the short is a pain!

3 Likes

I took the plastic mesh and all electrical tape off and separated each wire individually from my tail lights to the conjunction by my rear passenger door and all those wires are good I don’t see any cuts, pinches or naked wire.

I have not checked the wires that run from the rear passenger door, under the carpet and seats and centre console to the fuse box. No chance it can be the fuse box itself?

Thank you @shadowfax and @Mustangman for your help! I will continue to search for this wire grounding itself, and update with any results.

Cheers!

Hook the hot wire to your ohm meter with the fuse pulled. The other end to ground. Or a test light. Start wiggling wires in the harness. You wiggle and the ohm meter registers or test light glows. Might help you find the short.

There’s always the chance, but it’s more likely that the nice, flexible (and therefore breakable when they age and become more brittle) wires covered in insulation that rodents like to eat would be the culprit. :wink:

Do you have an aftermarket alarm in the vehicle?

Thanks! @Mustangman, Gotta get my hands on a multi meter. That is a helpful suggestion because that would help narrow down the area the short could be in considering the amount of wires.

No I do not have an after market alarm. Its the factory alarm that came with the vehicle… at least I think it is, the key fob is still the original Honda key fob.

Thanks @shadowfax, Looks like i’m going to have to strip and trace wires if that’s the case.

If your home’s water meter shows you have a leak somewhere on your property but you can’t see any wet spots you’d start by turning off segments of the piping and seeing if the leak goes away or not , right? Same idea, start by removing the fuse and the bulbs for that circuit, then use the car’s wiring diagram and an ohm meter – isolating branches with temporary disconnections. You’ll eventually figure out which branch the short circuit is occurring.

Even if you know which branch it is, can still be pretty difficult to find the exact electrical short location without unraveling the wiring harness. I had a wiring harness problem one time caused by battery acid getting into the harness and creating problems right in the middle of a big thick bunch of cables. That was definitely a chore to find.

As an alternative this relatively inexpensive gadget is designed for finding electrical short circuits in complex wiring harnesses. Read the pdf file manual for how it works. Conceivably a person could power the circuit and use a magnetic compass to detect the magnetic field caused by the current to find where the short is too. You’d notice a strong magnetic field right up to the point of the short, then the field strength would drop off markedly after the short.

https://www.harborfreight.com/cable-tracker-94181.html

Hey…don’t go stripping wires n such… there are ways to find a short in wires that does not require you to go Ape Sh*& and tear apart your vehicle and the wiring. I used to be a professional ICE (In Car Entertainment) installer for many years, so I have extensive 12vdc vehicle electrical system exposure.

I’m not going to try to outline it all for you here as that would not be practical… However you are on the internet so you need to start looking into how you find wire shorts, get yourself a Digital Volt Meter at the very very least. They also make devices (Power Probes) to suss out wire shorts…so look into that as well.

Quick and dirty tip?..If you have fuses in your panel that divide your light system up into quadrants… pull one fuse at a time to remove that quadrant from the test…if you stop blowing fuses upon test… you just got closer to the source of the fouled wire. I’d rather you use a DVM to measure resistance and or continuity to ground rather than the “fuse pop” method…but…

Let us know how you make out… At least you dont have this issue on a late model S class Mercedes…I promise you have no idea the complexity of those damn things)

thanks for your help @George_San_Jose1, I appreciate your input. I’m actually going to get a multi meter and cable tracker to help assist me in this search for the broken wire.

Thank you @Honda_Blackbird, Trust me that’s the last thing I want to do. Thank you for your input I will give that method a shot. I agree the “fuse pop” method is a pain, and I couldn’t even imagine how difficult those must be. I’ve been stuck on this Honda for about 2 weeks, this will be the third…

Love my power probe.

Yes… you have many avenues to research on how to locate a short in any circuit. Like i mentioned prior…you will need at the very least a DVM…these are inexpensive tools that can do a wide array of functions if you know how to use it correctly. The instruction manual that comes with it will be very informative to you.

The Power Probe I mentioned is another very useful item as @tcmichnorth surely knows…they are sometimes invaluable.

Anyhow…look on the internet on how to locate shorts in circuits…there will be plenty of information out there for you to read through I am certain of this. Also look at how your fuse panel divides your lighting system… If you notice that each corner is isolated by fuses…this is a good thing. Each mfg goes about circuit protection in a different manner…some divide it front to rear…others divide it into 4 corners… the more divisions the better in your instance.

If you have it divided into 4 corners…simply pull one fuse at a time and repeat whatever action you performed that would blow a fuse. Do NOT install any fuse that is rated higher than what was there prior… If it has a 10 amp fuse…replace it with another 10 amp fuse…do not install anything stronger…weaker is ok… but def not stronger.

If you pull say the front left quadrant and do your test and the fuse does NOT blow… you now know the fault is in the front left quadrant somewhere… So this isolates and concentrates where you need to look and what you need to repair. Savvy?

Let us know how you make out.

Look next to the fuses at the auto parts store. You will find resettable circuit breakers in the same form factor as the fuses. Buy one of the same amperage rating as your fuse. This will cut down on the number of fuses being consumed during diagnosis.

You absolutely need a schematic at this point. You’ve done everything anyone would have done to try and track it down but the easy stuff has been ruled out.

There are various tools already mentioned to help in the diagnosis. I prefer a meter called a differential ohm-meter. It basically is able to read very small amounts of resistance by powering the cable and then making very accurate voltage measurements. As you progress down the cable, you can see if you’re getting closer to, or farther from, the short.

@TwinTurbo @Honda_Blackbird @George_San_Jose1 Thanks guys for all your input and advice! I have finally found the problem, it turns out the aftermarket harness for the stereo was shot. Somewhere there was a short in the harness, with the harness unplugged the fuse doesn’t pop, as soon as I plug in the aftermarket harness for the stereo POP goes the fuse.

My solution? I actually have 2 of the same car, just one of them is in pieces. So I will reconnect the factory stereo from my parts car until I get the aftermarket harness properly rewired.

Thanks again and HAPPY NEW YEAR!!

1 Like

Congrats! Nice way to start the year off with a good find! Btw- how do you know it’s the harness and not the actual radio? I would suspect a radio failure before a harness going bad in-situ. Is there something obvious with the harness?

If you can take a photo of your aftermarket harness without any tape that holds all the wires together in a bunch… I bet I can tell you whats wrong with it… IF the issue is with the actual setup of that harness.

Sometimes knuckleheads will wire up the power antenna or amp trigger output wire into the dimmer circuit or something silly like that… and trust me…that will blow fuses.

I know the colors by heart as they have gotten standardized some time back… so its easy to spot problems when I dont have to look at a schematic.

I dunno… just thought it was worth a shot and possible if the issue is with how someone wired the harness. Let us know