Battery Light On ... with the key out.. new engine

[Leo1998]

Not sure if it helps but isn't the engine a 2002? is all the electrical the same as the 2001.5 you had in it? Just a thought.

Another thing i read is that Nissan doesn't supply the ignition switches and so the colors on the wires are not the same. Maybe change the wires you soldered around? That is another maybe as to why the FSM wiring diagrams don't match what you are seeing.

[Leo1998]

check this ground: http://www.nicoclub.com/FSM/QX4/2002/EL.pdf
because you said your power steering was giving you issues and it looks likes that ground covers the alternator too.

It also looks like the 2 grounds on top of the intake doesn't effect the alternator.

[4xq]

Hey guys, haven't had time to check in here for awhile.

Congratulations on getting the engine in! Looks like you have a gremlin tho.

Getting late and I need to hit the sack - I think this will work:

1. Key off, engine off.
2. disconnect the alternator connector.
3. Now Measure voltage on pin 2. ( should be the top pin when the connector is plugged in to the alternator.) You should see battery voltage. This pin always has battery voltage - there is a small fuse between it and the battery.
4. And now measure voltage on pin 1. It should be zero. Your charge light will be off. If you have zero volts, you have verified that the charge lamp circuit is working properly - it has zero volts on it with the key off.
5. Plug in the alternator connector (key still in the off position). Your charge lamp will light up. This tells you the voltage source is coming from the battery via pin2. That means something is wrong internally in the alternator. Bad diode, maybe something in the voltage regulator. I'm guessing you will need a rebuilt.

That alternator probably got a pretty good drink of coolant when the radiator went.

This also checks to be sure your pigtail is soldered correctly. You can see plug pinouts under "check the S terminal voltage" in the starting/charging section of the FSM.

Off to bed!

[CanuckQx4]

Not sure if it helps but isn't the engine a 2002? is all the electrical the same as the 2001.5 you had in it? Just a thought.

Not sure if the engine is 2001 or 2002, but the 01/02 wiring appears the same in the manual, but the alternator that is hooked up came off my original engine, and the wiring harness is original to the car aswell.

1. Key off, engine off.
2. disconnect the alternator connector.
3. Now Measure voltage on pin 2. ( should be the top pin when the connector is plugged in to the alternator.) You should see battery voltage. This pin always has battery voltage - there is a small fuse between it and the battery.
4. And now measure voltage on pin 1. It should be zero. Your charge light will be off. If you have zero volts, you have verified that the charge lamp circuit is working properly - it has zero volts on it with the key off.
5. Plug in the alternator connector (key still in the off position). Your charge lamp will light up. This tells you the voltage source is coming from the battery via pin2. That means something is wrong internally in the alternator. Bad diode, maybe something in the voltage regulator. I'm guessing you will need a rebuilt.

edit: the sentence below may have the test done incorrectly, but these were my results, next post I will clarify
The top wire when connected is the black/yellow, I disconnected it and there is no voltage on that pin, there is no voltage on the other pin either.

[CanuckQx4]

I lied. I realized I still had the cluster out of the car and all disconnected when i tested the ALT plug voltage. I put that back together AND

I do have voltage on the black/yellow, BUT I also have 12 volts on the other wire aswell

Does this also mean the alternator is messed up? I would think not since the connector is not even plugged into the alt while doing these tests...

Sounds like were onto something

I also noticed the alternator ground cable that bolts to the back of the case, it simply bolts into the case with a 6mm bolt, but there seems to be 3 threaded holes in the case on the back, I currently have it bolted in lower of the 3, just a half inch above the positive post. Would it make a difference to move it to the upper holes? I believe I have it in the correct spot because when I removed the alt and harness from the original engine, I put the bolt back in place to not lose it. But maybe I put it in the wrong hole.. if it makes a difference

[Leo1998]

Sorry about that Canuck the link for the ground i posted is on page EL-21
It looks like its on the block.
Here's how a diode works...A diode is a semiconductor that passes current in one direction only. The stator of the alternator generates three phase AC in a delta configuration. The six diodes are connected in a full wave bridge configuration that converts the AC to DC. At any instant of time, only two diodes are conducting, one to ground, the other to the battery. As the alternator spins, each phase takes turns, and the diodes turn off and on in turn as well. The result is a DC voltage with relatively little ripple.

[Leo1998]

[URL=http://imgur.com/VLS9JWY][img]http ... .jpg[/img][/url]
Here's what my alternator looks like, the yellow/black wire you can see in the plug, the ground on the bracket, the red boot is the HOT wire and that wire you are talking about on mine is by the plug and HOT wire, I couldn't get a picture of it but it's the one closest to the plug/red boot.

[4xq]

Ok, looks like some conflicting info in the FSM. I am looking at the 2001 FSM, page sc-20, which is the charging circuit.

Connector E-106 is the alternator connector, and near the bottom of the page it shows pin one on the left. So does sc-25.

sc-27, which I looked at last night shows E-106 with pin 2 on the left.

Leo1998s picture shows the black yellow wire at the top of the connector. Could be the same on a 2001, I'm just not sure.

See the following post.

[4xq]

I'm using the 2001 FSM , page sc-20, charging.

-Looking at the charge lamp circuit, the only source of voltage is supposed to be from the ignition switch when turned to on or start, through fuse #8 which is 10 amp.

-The other circuit is a power circuit for the alternator, always hot, through fuse #65 which is 7.5 amp.

-These two circuits are separate, and do not connect anywhere.

So, I think you can test this as follows:

1. Hook everything up, fuses back in and alternator plugged in. Your charge light should be ON with the key off. (We are back to square one).

2. Pull the 10A fuse #8. This disconnects the ignition switch circuit and rules it out as a source of voltage with the key off. Your charge light should still be ON if I understand correctly.

3. Pull the 7.5 amp fuse #65. The charge light should go OFF. If it did, you found that the alternator battery circuit (which is not the main charge circuit) is providing voltage back to the lamp somehow.

4. Put the 7.5 #65 fuse back in ( Other fuse is still pulled). Charge light will be ON. Pull the alternator connector. Charge light should go OFF, because the two circuits are not connected.

If the charge light is still ON, then your problem should be:
- Pigtails were soldered backwards.
- If you pulled the terminals out of the connector for soldering, you soldered wires correctly but you reversed the terminals when you plugged them back into the alternator connector.
- You have a direct short somewhere between these two circuits.

If the light goes OFF when you pull the alternator connector, there is an internal alternator problem. The alternator is somehow providing voltage back to the lamp circuit, which should not happen.

Sorry I can't help in figuring out for sure which is pin 1 on the alternator connector. That would help in making sure you are wired correctly.

[Leo1998]

@QX4...I asked him after he got the new engine what year it is and he said the vin says it's a 2002 and his rig is a 2001.5, so i was comparing the two fsm pdf's and there are some differences in the wiring.

[4xq]

Thanks Leo, missed the year thing. I checked the 2002 FSM page sc-20, and it is the same. The same inconsistencies are still there on pin references.

The test above should work the same.

Probably won't get a chance to check back in here for a few days. Hope it helped!

[CanuckQx4]

2. Pull the 10A fuse #8. This disconnects the ignition switch circuit and rules it out as a source of voltage with the key off. Your charge light should still be ON if I understand correctly.

That is incorrect, pulling this fuse #8 is what causes the light to go out. Does that skew the testing at all

I will still try and do your tests when I get home, wish I didnt take the girlfriend out now because I could really use some help on this! I wanna drive it down the road atleast soooo bad

[4xq]

Confucius say: If you spend more time with your car than your girlfriend, you will have no girlfriend in short order.

Let me think a bit, I'll post something before I hit the rack.

[CanuckQx4]

I appreciate it alot kind sir! Life saver!

[4xq]

Quote #1
I noticed that when I turned the engine off, and turned the key backwards, the battery light popped on, turn the key to where the fuel pump primes, and it goes off and stays off even with the engine running. But if your turn the key back, or even pull it out of the ignition, the battery light remains lit.

Quote#2
SO I disconnected the battery, disconnected the alternator plastic plug aswell as the power wire coming off of the alternator output post (secured it away from grounding) and then reconnected the battery, and the battery light is still on in the dash.

Quote#3
I found that if I pull the ALT fuse underhood the light will go off.

Quote#4
And no the ALT fuse in my car is in the under hood box (fuse 52)

Quote #5
That is incorrect, pulling this fuse #8 is what causes the light to go out. Does that skew the testing at all

I pulled all those quotes together for easy reference. That last quote did change things.

What should happen:
You turn on the ignition switch, which powers a relay, which turns on a bunch of circuits all at once, including the charge lamp circuit. The ALT light comes on until you start the car. The alternator generates voltage, and the voltage regulator effectively turns off the charge lamp by interrupting the ground for the charge lamp circuit once it senses enough volyage output from the alternator.

There should be NO other voltage supplied to the charge lamp circuit per SC-20.

What is happening:
You have power to the charge lamp with key off, which should not happen. You said the light turns off when you pull fuse 52, but the FSM says fuse 65. I am guessing fuse 65 is correct, because it is in the same position as fuse 52, just on the other side of the box. You just looked at the diagram backwards? Both are 7.5A.

So you know fuse 65 is sending power to the charge lamp circuit, and it should not be. Since that still happened with the alternator plug disconnected ( Quote 2), the alternator does not have anything to do with THIS problem. It was physically disconnected from the wiring system, but your charge light still came on with the key off.

Here is the hard part to explain (and your last quote pointed this out): With the key "OFF", power is turned off at the relay, and all the fuse box circuits that normally have 12 volts with key "ON" go to zero volts. Those are on one bus in the fuse box. BUT, Power is still coming into the charge lamp circuit from fuse 65, which is always hot to the battery. Voltage is now going to flow *backwards* through the charge lamp, to the fuse box, where it is finding a ground by flowing onto one of the other circuits on that bus in the fuse box (might be the reason for the "dim" brake light you noted). You are able to stop this by pulling fuse 8 in the fuse box (bet the dim brake light goes out).

So, to fix the problem you must figure out how power from fuse 65 is getting over to the charge lamp circuit.

To verify the ignition switch is not a problem:

1. Pull fuse 65 under the hood. Leave fuse 8 in.
2. With key off, check for 12 volts on pin 68. Should be zero.
3. Now with key to "on", check for 12 volts at pin 68. Should be 12 volts on your voltmeter.

If that checks out (and it should I think), I would pull the alternator and check your soldering job on the new pigtail very carefully, looking for a short.

(Edited because I forgot to include the quotes)

[CanuckQx4]

I'll show some pics then explain.

The alt wiring after cutting off the loom/elec tape


After cutting off the outer shrink wrap


So I did your tests above, everything was as you described and then got to the point of checking my wiring, even though I was sure the wires were shrink wrapped individually, then as a pair, them loomed, then electrical taped, as the pics show.

But sure as s***, I moved the wires away from eachother, and the dash light went out. Hold them close together, back on, I even held them in a cross pattern against eachother, and the light stayed on.

I wrapped each wire in a few wraps of electrical tape, and then together, and that solved it.

So in conclusion, the shrink wrap Im using from radio shack is aparently very poor quality and one could say even conductive! How brutal is that?

I appreciate every bit of help Ive had along the way, my steering is also back to normal and easy as pie. Thank you so much guys

[Leo1998]

Glad you fixed it Canuck and we learned a lot about electrical along the way. Now take that girl out to dinner and enjoy yourselves.