Tail lamp fuse

Topic: Tail lamp fuse (Read 8708 times) previous topic - next topic

Tail lamp fuse

April 03, 2015, 01:48:53 PM

I noticed I don't have tail lamps when I turn my marker lamps on. I pulled the fuse and it was blown. So I put another 10 amp fuse in and it popped as soon as I hit the light the marker lights. My best guess is would it be a short to ground? Can anyone give ideas what it may be? Thanks for the help.

Tail lamp fuse

Reply #1 – April 03, 2015, 03:28:30 PM

If you've been working under the dash, you might have pinched a wire. I know one time I dropped the steering column in my mustang and pinched one of the lighting wires in the bracket when I put it back up. Shorted, smoked, scared me to death, thought my car was on fire, etc. Good times.

Tail lamp fuse

Reply #2 – April 03, 2015, 04:48:55 PM

That could be exactly what happened. I was messing under the dash alot. I'll have to follow the wires. Thanks CoogerXR

Tail lamp fuse

Reply #3 – April 05, 2015, 03:07:39 PM

Follow brown wires :)

Tail lamp fuse

Reply #4 – April 06, 2015, 03:47:09 PM

Brown. Got it. Thanks Trinom

Tail lamp fuse

Reply #5 – April 15, 2015, 08:21:59 PM

So while using this schematic as a guide, I turn on my parking lights, and I have them up front, along with marker lights. The tail lights however are alll out. When I put a new fuse in and it blows as soon as it turns on, it tells me that it is short to ground on the brown wire. But because only the tail lights don't work, does that mean that the short is between the fuse and the tail lights? Or could the short be between the fuse and the light switch? I thought if it was the latter, then no lights would work. Am I correct?

Tail lamp fuse

Reply #6 – April 16, 2015, 01:50:59 AM

Yes, the short is below fuse 15 in the diagram.
That also includes the lamp-out warning module as well as the bulbs.

Tail lamp fuse

Reply #7 – April 16, 2015, 08:03:47 AM

Oh alright. That is great info. I was unaware of that since it doesn't appear that way on the diagram.

Tail lamp fuse

Reply #8 – April 16, 2015, 08:43:33 AM

Also check the light blue w/ red stripe wires under the dash and behind the radio. These are the dash illum + wires. They show ground when the lights are turned off causing them to be used as ground when hooking up accessories like gauges or radios. I install car audio and see this mistake quite often. This will also cause the tail lamp fuse to blow in most cases.

Tail lamp fuse

Reply #9 – May 17, 2015, 10:01:57 PM

Here's a random thought....some guys at work said it could be my tailights bulbs themselves? That they may be grounded through the bulb? And if I bulb shorted, that could be blowing the fuse. Is this myth? Or could this be possible?

Tail lamp fuse

Reply #10 – May 18, 2015, 03:21:05 PM

I've never seen it on any of my cars, bit it is possible.

Do this first.

You have both illumination and brake light signal wires for power. To blow a fuse, it pretty much has to be grounded out. Check for negative on your tail lights first. If you have a ground, you know both which wire it is, and that it is somehow directly shorted out

Tail lamp fuse

Reply #11 – May 18, 2015, 03:48:57 PM

Quote from: Haystack;448135

Check for negative on your tail lights first.

I'm sorry to be ignorant, but I'm a bit cloudy with how to go about checking for negative on the tail lights. Please inform me on how to do this. Sorry again

Tail lamp fuse

Reply #12 – May 18, 2015, 05:33:47 PM

Quote from: FOX-XR7;448122

Here's a random thought....some guys at work said it could be my tailights bulbs themselves? That they may be grounded through the bulb? And if I bulb shorted, that could be blowing the fuse. Is this myth? Or could this be possible?

Probably more myth than reality... Easy to test, remove all the bulbs on the supply side of F15(to the south of fuse), if fuse still blows, that ain't the problem...

If signal & brake lights are normal, not likely a problem with the tail lamp bulbs, though I have seen a busted bulb cause a short(start checking side marker, license, etc bulbs)...

My bet is there is a pinched brown wire somewhere between fuse and tail lamps...

BTW assuming you have the feature, there is a possibility of a issue with the lamp out module...

Tail lamp fuse

Reply #13 – May 18, 2015, 06:57:30 PM

Quote from: Haystack;448135

Check for negative on your tail lights first. If you have a ground, you know both which wire it is, and that it is somehow directly shorted out

Huh?? Ground supplied to bulbs is same as a connection to body/chassis, if it shorts to body no foul, no harm... If ground were shorted to supply(brown wire, or a internal short in bulb), it's still same as supply wire shorting out to ground...

If ground were missing the lights would not burn but would not blow the fuse... I had this problem with backup lights on the '95 LX, ground wire to sockets was broken at trunk hinge...

Tail lamp fuse

Reply #14 – May 18, 2015, 09:00:52 PM

Sorry, i didn't describe that properly.

Grab your volt meter and check your positive wires at the tail light, and look for a ground on the positive wires. You have the illumination lights, turn signal or brake wire that could be shorted out.

You can either do a resistive test from a good know ground, or find a power wire that works and see if you have voltage, looking for ground on a positive wire. That way you can at least rule out the other wires, and measure different parts of the car to see where the fault is. Worst case scenario, you figure out which wire is bad and run a new wire to replace it.