Stumped: Headlight and shifting glitch

[MeltedMonitor]

The car is a 92 240SX Convertible A/T (getting ready for the SR/MT swap) and it has about 130k on it.

Friday I was driving it with the top down, headlights on, A/C full blast and the stereo blasting. I parked and returned to the car a few minutes later. I started it and attempted to shift to reverse but the shift lever release did not activate. Hmmm. So I manually pressed the release button and shifted into reverse. I backed out, and put it in drive and floored it. It started off in fourth gear and did not downshift into a lower gear when it was floored. To make things stranger, the headlights did not raise when I turned the headlights on (they did turn on, however, but just stayed lowered).

Recap:
- Shift lock does not release
- Transmission shifts strangely
- Headlight buckets do not raise but headlights come on

So I parked the car for the weekend assuming a fuse blew. I checked all of the fuses today and discovered one blown fuse, the reverse light fuse (bottom right 10A in the interior fuse panel). I replaced it and started the car. Pop. I used my 12V test light to determine that there was ignition-switched 12V coming into the fuse, but the other side of the fuse showed a ground. This was causing the fuse to blow when the ignition was turned on.

So I pulled out the manual trying to make sense of this. That fuse powers the reverse lights, the shift interlock and the gear selector lock mechanism (two different things?). I have NO idea how the headlights are affected by this and I have NO idea what to start unplugging to check for a shorted mechanism.

If you have any experience with this, or a good direction to begin then please let me know. I know I can figure this out, but I figured I would start by seeing if this has happened to anyone else first.

Darren

[Evo34wd]

probably a haunted 13 : P

[idlafie]

The car is a 92 240SX Convertible A/T (getting ready for the SR/MT swap) and it has about 130k on it.

Friday I was driving it with the top down, headlights on, A/C full blast and the stereo blasting. I parked and returned to the car a few minutes later. I started it and attempted to shift to reverse but the shift lever release did not activate. Hmmm. So I manually pressed the release button and shifted into reverse. I backed out, and put it in drive and floored it. It started off in fourth gear and did not downshift into a lower gear when it was floored. To make things stranger, the headlights did not raise when I turned the headlights on (they did turn on, however, but just stayed lowered).

Recap:
- Shift lock does not release
- Transmission shifts strangely
- Headlight buckets do not raise but headlights come on

So I parked the car for the weekend assuming a fuse blew. I checked all of the fuses today and discovered one blown fuse, the reverse light fuse (bottom right 10A in the interior fuse panel). I replaced it and started the car. Pop. I used my 12V test light to determine that there was ignition-switched 12V coming into the fuse, but the other side of the fuse showed a ground. This was causing the fuse to blow when the ignition was turned on.

So I pulled out the manual trying to make sense of this. That fuse powers the reverse lights, the shift interlock and the gear selector lock mechanism (two different things?). I have NO idea how the headlights are affected by this and I have NO idea what to start unplugging to check for a shorted mechanism.

If you have any experience with this, or a good direction to begin then please let me know. I know I can figure this out, but I figured I would start by seeing if this has happened to anyone else first.

Darren

Check the wiring leading to the reverse sensor on your tranny housing - make sure it isn't cut or shorted out. IF the wiring is okay, then pop the inside trunk cover leading to the reverse lights. Check the wiring leading to the bulbs, the base of the bulbs or the grounding point the bulbs use. You could have shorted something out there.
Give those both a check & see what you find.
Good luck!!
ID
'95 SE

[MeltedMonitor]

I think it may be something on the tranny, gut here is another observations:

- Headlights go up and down using the button on the dash

Also, I forgot to mention that I had completely unplugged the taillights when testing the circuit to eliminate them. I still showed a ground.

Gonna start checking tranny things... any other replies would still help, though.

Darren

[MeltedMonitor]

So I finally figured out what the problem was... this is important because it is very likely that this could happen to someone else.

The main chassis wiring harness runs inside of the left fender above the wheel. With my larger wheels and tires, and my lowering springs, the tire rubbed through the splash guard and slowly eroded the insulation from the closest 10-15 wires in the bundle... shorting them all together.

No WONDER none of the symptoms made any sense!

Darren

[idlafie]

So I finally figured out what the problem was... this is important because it is very likely that this could happen to someone else.

The main chassis wiring harness runs inside of the left fender above the wheel. With my larger wheels and tires, and my lowering springs, the tire rubbed through the splash guard and slowly eroded the insulation from the closest 10-15 wires in the bundle... shorting them all together.

No WONDER none of the symptoms made any sense!

Darren

Ouch!!!...yeah you're not the only one that has had that problem. I've heard of a few 204SX owners who've lowered their cars & have put bigger tires & rims only to have had the same thing happen to them. Their solution was usually rerouting their wires thru the engine compartment.

Anyhow, thanks for letting everyone know what the cure was. Hopefully it will remind people with lowered cars, big rims & tires to check their wiring harnesses in the fenderwell when gremlins start to hit.

ID