Electrical Woes

[Solo_S14]

So kind of a shot in the dark here, but as I start digging into my wiring issues, I figured that I'd post up and get any advice/tips from you guys that have faced these problems before.

1) Brake lights not working.
- 10A fuse is blown, and it blew another spare as soon as it saw power.
- I had removed the ABS wiring and control unit from the rear end of the car last year, but didn't touch the main rear harness.
- Rear running lights and turn signals work fine.

2) Reverse lights not working
- Reverse plug in transmission is plugged in, no promises on condition of the plug itself and the associated wiring
- Thinking it might be the same issue as the brakes, as they are both on the same harness

3) Horn not working
- My horn has always been on/off, mostly because of a crappy connection at the hub (spring not making contact with the metal contact ring), however I pulled the spring into position with the wheel off, and it still doesn't work
- Not sure what to think here, I guess I'll start in the FSM for each problem and begin chasing wires.

Any help with these issues would be great, as I'm going back to work on Tuesday, and I'm trying to get to AutoX in the morning, AND an out of province inspection on Monday!

Thanks guys.

[Matt93SE]

first thought on the stuff in the back... check the bulb sockets themselves and the harness ends for any signs of ugly.
the older Maximas has an issue with junk sockets melting and shorting the harness to the rear lights.

that's all I can come up with, unfortunately.
g'luck

[Solo_S14]

So far I've started at the rear high mount, and traced continuity through both rear lamps and to the tail harness connector (T2 in the picture). When the tail harness is unplugged, there is no cross-continuity (short) with any of the other wires in the harness. So the tail harness itself should be good.

However once I plug T2 into the Body harness (B25) I get a short throughout the entire tail harness.....so I guess that the short is somewhere in front of the tail harness. What I mean is, I'm guessing that somewhere ahead of this, the stop lamp wire is shorted to EVERYTHING in the tail harness, so I'm thinking crappy connector as well.

Just pulling things apart under the dash right now, but if anyone has any insight on that bit so far, feel free to speak up.

[Solo_S14]

Ok, so the tail harness is good from the previous tests.

I have now tested the entire body harness (B1 to B25).
After finding the stop lamp switch wire on B1 I tested to the same wire on B25 with continuity, and NO short to the other wires within B25. I then plugged the body harness into the tail harness, and can get a good test from B1 all the way to the stop lamps, with NO short at the tail lamp connector, or at the tail harness at (B25 = T2).




So far both the tail harness and the body harness are good, and display no shorts across wires. However when everything is plugged in, I get a short across the entire tail harness, which means that something is shorted in the main harness.

The only connection left now is the wire between the M11 junction and the M25 stop lamp switch. The only thing I guess I can do now is check for shorts between the wire at the stop lamp switch and the rest of the connections at the M11 junction.






There is a side connection to the rear wiper amplifier at M2, but I don't have a rear wiper so it shouldn't affect anything. If the junction at M11 isn't shorted, then I'm not really sure what else I can check, because the short doesn't exist until this is connected. Maybe there's something shorted at the fuse box, I guess I could pull it apart and check for crap in that fuse location.....???

[Solo_S14]

So the connector at M25 is NOT shorted out.
Wire from M25 to M11 is good.

Here is the issue:
Fuse positive at M7 to connector at M11 shows 12V.

This should not be possible unless the connector at M25 was plugged in and the brake pedal is depressed. Power should travel through fuse, through switch at M25, THEN into M11.

12V also shows at the connector side of M25 which means that it's getting there through M11 and traveling in the wrong direction.


So am I safe to assume that the connector at M11 is pooched, and that I'm shorting power to this position? The connector at M11 should never see power until it travels from battery, through fuse, through closed switch, and into M11.

My 2nd issue is that the Red/Yellow wire at M25 should show continuity to the fuse, and I can't get this, so the fuse wouldn't even power the switch if it wasn't shorted. I hate electrical gremlins, any ideas about what I check for now?

Thanks again guys.

[Solo_S14]

The other night as I was posting this, I figured out the brake light issue and the horn.
However, I didn't have time to figure out the reverse lights, as I worked until 3:30am in order to get the car together for AutoX. AutoX was sweet, but now I once again have fully corded tires, lol.

I think the issue is somewhere in the ****ty auto - manual swap wiring.
If anyone has any good links or any explanation of the wiring I need to chase from SR 5 speed transmission, through what I suspect are some auto harnesses, and to the reverse lamps, I'd appreciate the info.

Thanks,

- JC