Today I took my 1997 Nissan Pathfinder to work, after I came back from lunch I notice that the tail lights were on in which I thought maybe the reflection of the sun is making it see that way. As I drove back home I came to notice that the tail lights, 3rd brake light were on even if the key was off the ignition. I thought to myself maybe it was the 3 light bulbs that were burnt may be giving it the problem on the 3rd brake light. I changed them and still they are on. I pop the hood open, removed the brake circuit and the lights were still on, so I decide to see if it was any other circuit that will turn it off. Since my panel is somewhat faded, there are two green fuses located on the left hand side panel. I removed one of them and the lights went out, so I got the other green fuse and connect to that location thinking maybe it is the fuse and turns out that the lights came back on again. What can it be? As for now I removed the fuse

My first thought would be a shorted multi-function switch, but, in order to be sure, one would need to get a wiring diagram and a 12v test light and do some checks. Another possibility would be wires that shorted together where the wire harness goes from the body to the rear hatch. Are there any aftermarket systems installed, i.e. aftermarket alarm system or audio system?

smj999smj wrote:My first thought would be a shorted multi-function switch, but, in order to be sure, one would need to get a wiring diagram and a 12v test light and do some checks. Another possibility would be wires that shorted together where the wire harness goes from the body to the rear hatch. Are there any aftermarket systems installed, i.e. aftermarket alarm system or audio system?

I installed a aftermarket radio about 3 months ago in which it did not gave me a problem, prior to that it had another radio (prior owner ripped it out). Other than that it has a stock safety system

smj999smj wrote:My first thought would be a shorted multi-function switch, but, in order to be sure, one would need to get a wiring diagram and a 12v test light and do some checks. Another possibility would be wires that shorted together where the wire harness goes from the body to the rear hatch. Are there any aftermarket systems installed, i.e. aftermarket alarm system or audio system?

My sister took the car right now without knowing that I took the fuse out in which the lights were on and the brake lights, just when she pressed on the brakes the brake lights wouldn't illuminate at all.

Makes sense since you removed the power from the circuit. If my memory is correct, neither the reverse lights nor the third brake light pass through the multi-function switch, so I would definitely take a look at the harness between the body and rear hatch. It's usually contained in a rubber sleeve. With the opening and closing of the rear hatch, the wires bend back and forth and can eventually break and short. If those wires look good and the bulbs in the tail lamps check out okay, I would begin my diagnosis by tracing the reverse lamp circuit or the third brake light circuit, as those would be the simplest circuits.

smj999smj wrote:Makes sense since you removed the power from the circuit. If my memory is correct, neither the reverse lights nor the third brake light pass through the multi-function switch, so I would definitely take a look at the harness between the body and rear hatch. It's usually contained in a rubber sleeve. With the opening and closing of the rear hatch, the wires bend back and forth and can eventually break and short. If those wires look good and the bulbs in the tail lamps check out okay, I would begin my diagnosis by tracing the reverse lamp circuit or the third brake light circuit, as those would be the simplest circuits.

I will go ahead and check on those, one thing I notice as well is that when I removed the fuse the radio doesn't work at all.

Maybe you already checked this, but I had the brake lights always on in my 94 due to the little rubber stopper falling out of the brake pedal (where the pedal hits the brake switch button). I replaced it with a plastic push in fastener and they've been working properly since.

Gporter wrote:Maybe you already checked this, but I had the brake lights always on in my 94 due to the little rubber stopper falling out of the brake pedal (where the pedal hits the brake switch button). I replaced it with a plastic push in fastener and they've been working properly since.

I came to notice that I found a small broken plastic tip on the floor, it was round, I ordered a replacement part I am hoping that I can fix it this weekend since tomorrow is my 6th day of work. Now another problem arise the check engine light came on and the OBD-II gave me the error 0420

P0420 is a Bank 1 catalyst efficiency code. Often that means the upstream, passenger side catalytic converter needs to be replaced, but could also be caused by a number of other things, such as exhaust or intake leaks, dirty injector(s), spark plugs, timing or the ECM. That said, if you don't have any exhaust leaks or intake leaks, it's usually the converter 99% of the time.