Keeps blowing tail light fuses.

[Coup D E'Tat]

I went to turn on the my lights, and when I did I noticed that my gauge cluster/AC stuff lights didn't light up. "No big deal, blown fuse," I said and drove off, with no gauge cluster lights. The gauges themselves worked, just no lights. After being pulled over for not having any tail lights, I remembered that the two blow out together - doh.

I replaced the fuse twice, but the car was still running, with the headlights in the "off" position, and it blew both fuses.

Do I need to have the car off or something, or does my problem lie elsewhere? Aside from wiring things together, like radios and AFC's, I don't know a whole lot about electronic stuff like this.

Thanks in advance.

 

[96TSi_Chris]

Mine did that about a year ago. I had to take the taillights out and trace the wires back til i found a short about halfway from the fusebox and tailights. Could also be a bad ground.

 

[Coup D E'Tat]

How would I go about finding a short? Will it be obvious, or....?

Also, a bad ground on what? The tail lights?

 

[nutshot]

How would I go about finding a short? Will it be obvious, or....?

Also, a bad ground on what? The tail lights?

Take a digital multimeter and find the resistance (measured in ohms) between the fuse block and the tail-lights. My guess is one wire is shorting, and that wire will have too much resistance (the other wires will have significantly less resistance).

 

[96TSi_Chris]

Mine was very obvious, one of the wires was frayed and almost in half. As for a ground, it could be a bad ground connection on the tails or any other unit thats on the same circuit as the tails. Im not sure what those are off the top of my head, but you can take a test light and see if you can eliminate some of those ideas so you arent searching all day long.

 

[Coup D E'Tat]

Alright, I will try the above a little later.

Does anyone else have any other possible solutions?

Thanks,

 

[Coup D E'Tat]

Could a bad relay be a cause the fuses to blow? I looked today, and noticed that there was a relay for the tail lights.

 

[2gGSX]

I'm having the exact same problem. My dumbass mechanic in a rush apparently put a 15a fuse into the 10a socket (for my turn signals), which thus definately caused something to short out. Would it be safe to just assume it's a turn signal ground wire?

 

[luv2rallye]

Could a bad relay be a cause the fuses to blow? I looked today, and noticed that there was a relay for the tail lights.

You blow the fuse with the key in the "on" position whether the engine is running or not - correct? But it never blows with the key in the "off" position I assume. The 15A fuse is after the taillight relay so it is unlikely the relay. There are dozens of things on that circuit any one of which may be causing the short. Keep the engine off for testing since it fails in just the "on" position. Before getting into measuring resistances (time consuming and you must know the circuitry and what you are doing, which you admit you don't) lets try some obvious suspect things first. Start by disconnecting the dimmer switch (rheostat) and see if that blows the fuse. If not move to EVERY single light on the outside of the car except headlights (ie. taillights, fogs, marker lites, position lites, license plate lite). Then start on radio, cig lighter, mirrors and interior things that might be suspect. I have the schematics and there are just too many things to list. But use common sense - is there anything you worked on or replaced recently? Anything that doesn't work is a suspect and should be disconnected.

You can save fuses by replacing the fuse that blows (temporarily and only for testing purposes) with a small 12 volt light bulb (don't try to start the engine with it in). If there is a short, it will lite. When you disconnect the item that is causing the short, it will go out (so it's a great detection device). Keep in mind the short may be in the wiring or fusebox which is harder to find, but check all the easier, more obvious devices first.

 

[Coup D E'Tat]

Sorry I haven't responded, but I switched the relay for the tail lights with the one for the horn, plugged in a new fuse, and the lights worked fine. This, however, was with the key in the "Off" position, and since the car isn't driving right now, I have not tested it in the "On" position (well, actually because I'm lazy )


Anyways, if I turn the beast on, and the fuse blows, I will begin checking for shorts, will I really don't want to do, but whatever.

Thanks for the help guys.

 

[Coup D E'Tat]

Update : I went to go for a little drive tonight, and I turned on the lights. Awesome, they all work. So, I let it sit for a moment to make sure, and they seemed fine. I put my foot on the brake to drop the e-brake, and I noticed the lights went out again.

I guess it could be a coincidence, but if the "brake lights" are the problem, how would I go about finding out what exactly the problem is? I'm going to pick up a light bulb tomorrow to put in the fuse slot to confirm that it is the problem, but I'm open to advice before hand.

Thanks,

 

[luv2rallye]

The stop (brake) lights are on a different circuit than the normal taillights and have their own fuse. You should be able to operate them even with the car turned off and blow no fuses. Try removing the stop light bulbs from the rear (or disconnect them) to see if the fuse still blows. Also try removing the normal taillight bulbs and see.

The stoplight switch also goes to the "turn signal and hazard flasher unit" which lites the normal taillights (brighter) along with the stoplights. Do your turn signals work without blowing fuses? If you have all the rear taillight and stop bulbs removed (or disconnected) and you still blow fuses with the brake pedal, then suspect this unit or a short in the wiring (look around the brake pedal switch to see if any wires are shorting to other wires or metal).

 

[Coup D E'Tat]

I am not sure about the turn signals, but I do know that the hazzards work, because the cop that pulled me over made me put them on

I'll give what you said a shot tomorrow. I really want to get this settled. I hate stupid problems like this.

You've been a great help. Thanks a lot.

 

[Coup D E'Tat]

Update : I took the trunk interior pieces out to inspect the wiring, and didn't notice anything wrong. I then went to check out the brake pedal wires, and didn't see anything, but most of it is wrapped in tape.

The reason I didn't check much is because I'm having a problem finding a "lamp fuse" or whatever they're called (the fuses with the light bulb.) I've looked at Home Depot, another local hardware store, and Radio Shack. There is an electrical store that carries just about everything, and they should have one, but they are not open after 5:00, so I'll have to wait until tomorrow.

Is there anything that you would reccomend me to visually check? Or should I just go over all of the wires for the brake lights, the whole way up to the dash?

Thanks,

 

[luv2rallye]

Yes - try removing the bulbs as in my previous post to see if the fuse still blows.
Also does pressing the brake pedal blow the fuse every time?

There isn't such thing as a lamp fuse and if there was that's not what I mean. I mean to actually use a real 12 volt light bulb such as your marker light or license plate light or even a taillight. You will have to either solder wires on it or get a socket for it with wires on. Then remove the fuse that blows and stick the 12 volt bulb wires into the slots where the fuse was. It will then light if there is a short when you activate that circuit (press brake pedal or turn on taillights depending on which circuit it's in. It will lite brightly if a short. It may lite half bright (along with the normal lite half bright) if no short and the normal light comes on.

 

[Coup D E'Tat]

Oh, alright. I was told by the guy at Radio Shack that lamp fuses do exist, which is why i was under the impression that they were what you meant.

Also, the reason I didn't try pulling out the bulbs was because I was waiting to use this method instead of frying more fuses.

Thanks,

 

[Coup D E'Tat]

I bought a pack of fuses today, and threw one in. The key wasn't in, so obviously, it was in the "Off" position. I pulled all of the plugs out of the tail lights, and it blew the fuse. I then noticed that my corner markers weren't coming on either, so I guess I should pull the bulbs out on those and see if it still blows the fuse?

 

[Coup D E'Tat]

Update : I think it's fixed!

I pulled out the two corner marker lights, unplugged them, and pulled the bulbs out. I noticed that the driver's side bulb was wet (on the outside) and that the water went all the way down to the connection. The rubber o-ring was old and beat, with a chunk missing out of it - I think water was getting in through here, onto the wires, and obviously creating a short.

I went to AutoZone, got two new o-rings, two new bulbs, and some of that bulb grease stuff (the stuff that's supposed to help keep water out.) I didn't plug anything in, but without the bulb or the connector plugged in, all the lights (minus the corner lights, obviously,) turned on perfectly.

I'm really hoping that was my only problem, but I guess we'll find out a little later tonight, because at the moment I have to go get my EPROM socketed.

Thanks for all the help,

Jesse

 

[Coup D E'Tat]

Update : Started blowing fuses again.

 

[Trejo'sGSX]

So, did you ever get this fixed???

I'm having the same problem.

 

[Coup D E'Tat]

Yes, the last time it blew was with my ECU on the "fritz." I have no idea if they're related or not.

After replacing the bulbs like I said earlier, I haven't had any problems

 

[2gGSX]

My problem was that I had a short in a rear right taillight wire. This is a major pain in the ass, so good luck finding it. What I did was test a bunch of sockets until I found that the rear right one was messed up. From there I determined which wire it was, and took out some foam stuff to look at the wires, and saw it was a green wire that went behind one of the metal pillars behind it, so we thought that might've shorted or something. Either way, we cut and spliced them to be in front of the pillar. After that everything worked out

Cliff's notes: it was a short

 

[Trejo'sGSX]

I found my problem behind the CD player, I was looking for the short I thought about looking behind the radiosince I had had a similar problem in my other car, so I did and boom, found the short, after taking the radio out I found a couple of wires melted together with each other so after spliting them apart and wraping them up with black tape everything works now.

 

[nek]

Damn tuners. You are good. I know this post is old as hell but it helped me fix my tail light problem. This site is one of the largest databases on the web! Can find anything on here!