Electrical gremlins...

[NissanNismoZ]

Alright, so, I've been messing around with a few things that dont work on pathy and it's this:

Alarm system

Fog lights

O2 sensor has a code, according to haynes, is a short somewhere.

 

First off, i check the pins running to the alarm system..it has power (a greenish wire?)

Both fuses are good, but have no voltage going to them?

My LED does not ever come on, but it does work, as i can make it light up with my voltmeter.

I'm just wondering how i can fix my alarm system, when none of the board looks burnt inside and the contacts are clean (older model alarm system..(94) it has blades? My 95's system wouldnt swap.

 

Okay, next the fog lights. The switch lights up when headlights are on, and my fog lights dont come on.

Okay. So now i check for voltage, and on my driver side, i have 13.5v (yes the engine was running) but yet..the bulb does NOT work??

I take a known working bulb off red pathy and it still doesnt work! yet, it has voltage?!

So i take an LED (since they dont take really much juice to operate) and..nothing!!

How can i have voltage, but no power?

 

My O2 sensor, as mentioned, the Haynes manual suggests there is a short in the wiring..if so, where can i look? (it's a code 33)

 

Thanks! Pretty sure these problems are much simpler to fix than any other problems the other pathy gave me..hah.

[ahardb0dy]

Fog lights - Bad ground, check for power at the wire that goes to the bulb and clip your ground clip ( if your using a test light) to the same place the bulb gets it's ground from.

[NissanNismoZ]

Done, that's where I got the 13.5v from was the power wire and the ground wire at the fog assembly.

I went ahead and tried using a test light, with no dice. Tried grounding at the battery, nothing. Tried grounding at the frame, nothing. My volt meter shows voltage at the power wire and wherever i ground it to!

That's what makes no sense..It says it has power, but..it seems impossible as it wont even power a test LED...

[Trogdor636]

Did you replace your fog light fuse?

[ahardb0dy]

So your saying with the test light you DON'T have power even when you ground the test light at the battery or the frame?????

 

But with a meter it shows power at the wire for the bulb??

 

Did you test the test light first at the battery to make sure it is working? If it is and you don't have power at the fog light wire than maybe the meter is wrong. If this is the case than I would go back on the fog light harness to see if there is a relay and check that.

[NissanNismoZ]

Yes! Test light works because I tested it at the battery before testing at the fog harness. My meter reads the same as battery voltage where ever I ground it and it's touching the hot wire of the fog light. If I turn the fog light switch off, voltage goes away..

That's why it makes no sense that I have voltage but.. No power?

Will do! Any clues on where the relay would be?

 

Also, if you mean the fuse by the battery, right off the hot side, then yes that fuse is good. (looks identical to the red pathys fog fuse and same location.

Thanks!

[Slartibartfast]

Voltage but no power could mean a bad ground, or really a bad/corroded connection anywhere in the system. The voltmeter doesn't need to pass much current to check for continuity, but the bulb draws a whole lot of juice. I rigged up a fishfinder for my neighbor once and had this problem: the voltmeter said all was good, but the unit wouldn't power up until we ran a new ground.

 

The fogs in mine didn't work when I got it, and the PO had given it an unsuccessful go (rat's nest). My dad stripped out the busted up factory wiring and just wired them up like he was fitting accessory lights. He tapped power for the switch at the fuse box, from a vacant relay slot. They're grounded to the firewall and fused where they hook to the battery.

 

I think my switch lights up when it's on, not with the headlights. I'm not sure if that's factory or my dad's work. Preference, I guess... one way you can tell at a glance if they're on, the other way you can tell where the switch is in the dark.

 

I'd crawl underneath and take a look at the O2 wiring. Mine was inexpertly rewired at some point and one of the wires was hanging out of the connector. It wasn't throwing a code, oddly enough. Anyway I'd just find the sensor, go along the length of wire as far as you can, and look for points where it might be rubbing, corroded, whatever.

 

I'm no help on the alarm, I haven't figured out how to make mine work either. Maybe it's like the door lock timers and they get cracks in the solder joints. I haven't really needed to use it so I figure I'll end up tearing it out.

[NissanNismoZ]

You may have a point.. The PO was a firefighter, so one of the fogs were wired into with their lights, i'm guessing.

So, I should wire my lights up manually? I just want them to work, as i use those connections for my brush guard fogs.

I'll try running a new ground first.

I remember i had a similar issue on red pathy, like say one of my connections went corroded on the fog on the dirver side, it knocked them both out, because when id wiggle it, both would come on, so it has me believing its wired in parallel somewhere?

Not sure.

 

I'll check the O2 now! Thanks!

 

Yeah, the alarm system..I like it, mainly because it IS a pretty funny sounding system, but, i like having that little bit of extra security, knowing that if anything happens, ill be able ot catch anything happening, plus, i liked having a remote.

 

Thanks! I'll post if i find anything out.

[NissanNismoZ]

Woo! Alright, so after researching and tracing down wires, I find that the power wires are even broken inside, but it would not supply enough power to light up my LED 's.. Finally. But. I decided to re-run the power wire from the relay, so now it works just like stock! Both fogs work perfectly and its normal now. Thanks!

Now only two issues left, o2 and alarm.. So tomorrow ill try tracing along my o2 sensor wires and see how that goes.

[ahardb0dy]

glad you figured it out, I was going to suggest as a test to connect the lights directly to the battery at least that would let you know if they worked, but you figured it out already.

 

 

Sorry no help with the alarm, first thing I did when I bought my 94 was tear it out.

[NissanNismoZ]

Oh yeah, they were known working bulbs from red pathy, and apparently the ones in there looked as new as the ones i just bought for red pathy a few months ago, so maybe they tried to diagnose it as well..but not deeply.

Thanks though!

 

I'll be checking the continuity of the ground and power wires to see if they're any good..same goes with the o2 sensor..

[Alkorahil]

Oh yeah, they were known working bulbs from red pathy, and apparently the ones in there looked as new as the ones i just bought for red pathy a few months ago, so maybe they tried to diagnose it as well..but not deeply.

Thanks though!

 

I'll be checking the continuity of the ground and power wires to see if they're any good..same goes with the o2 sensor..

 

 

Make sure to read the FSM on how to test the O2 sensor. There are some cautions notes in there. You dont want to fry your ECU!

If you replace your O2 sensor it will replace everything from the sensor forward to where it connects into the main harness on the right side of the engine bay. You might be surprised how much peppier/better the truck runs with a new O2 sensor. Just a thought. (just dont get a universal 02 sensor)

[Alkorahil]

First off, i check the pins running to the alarm system..it has power (a greenish wire?)

Both fuses are good, but have no voltage going to them?

My LED does not ever come on, but it does work, as i can make it light up with my voltmeter.

I'm just wondering how i can fix my alarm system, when none of the board looks burnt inside and the contacts are clean (older model alarm system..(94) it has blades? My 95's system wouldnt swap.

 

No power to the LED on the switch sounds like a connection problem between the alarm brain and the switch itself. I know it you dont have the switch plugged in (or its bad) the alarm system will not function (completes the circuits). Even though you can get the LED to light up, I would try swapping switches with a known good switch. I would also follow the wires from the switch to the brain box. under the carpet, etc. It goes under several tight points and might have gotten pinced (just thinking outside the box)

IIRC correctly also, same with the wires/connections to the pin switches for the doors. Without them attached the brain doesnt know what to do.

 

 

I have the troubleshooter flowchart at home. I will see if it has any insights.