gtd2000

***Sorted***

100A Blue fuse was the problem

I recently had a problem with the battery on my S14 not charging and expected that the Alternator was dead.

Took alternator to Advance and it tested OK.

Now that I've got the battery charged and the car running I've now discovered another (larger problem) even although it appears that the alternator is still not charging the battery...

I have no power to almost everything in the car...

No dash lights when I turn on the ignition (but the car starts fine)
The only thing that lights up is the clock but the LCD part is not displayed
The windows do not operate
The radio does not come on
The front and rear lights are not working

The air blowers change position and the a/c kicks in as I heard a change in engine note and the selector switched illuminate but the fan does not work.

All of the fuses appear to be OK...

The only thing that looked bad when checking everything was the red connector block on the positive battery terminal which I have disassembled and removed to get good connections....

Could removing this red terminal connector cause all of these issues?

gtd2000

Some further information:

Well yesterday I went to the local breakers yard and picked up a length of cable from a Maxima that uses the same battery terminal arrangement as the 240SX.

I disassembled this and used the new red connector (which is in great shape) and put this onto my car.

No change in situation..

I'm trying to see the logic in this but it's certainly escaping me at the moment - there must be something I'm overlooking that gives power to all of the accessories but allows the car to start..?

When you connect the electrics to the battery there is the main cable and then two separate smaller gauge cables that connect into the red connector block can anybody advise what the function is for the following:

1. The thick large sized cable.
2. The two smaller cables going into the red connector.

I noticed that on many cars at the breakers yard the red connector has simply been cut off and the two smaller cables simply connected to the battery terminal - makes me wonder why you'd need the red connector in the first place?

I tried hard wiring the two connectors to the battery terminal as well as the other thicker lead and no change to the situation.

I've now put it all back together using the red terminal block and the normal layout.

Car is starting fine - looks like my front light work on dip and full beam but not the rear lights. Side lights and brake lights are also not working....

Something that's just come to mind here....

Before any of this trouble started - the real problem I had was a leaking fuel tank - cracked at the support strap on the passenger side.

I did disconnect the wiring to the fuel tank as I was going to drain it from the top (which didn't happen in the end). When I first tried to start the car - I forgot to reconnect the connectors.... I noticed at that point the LCD part of the clock did not light up black and then when the car just kept turning over realised that the fuel pump wasn't connected!

Once I reconnected the wiring the car started but died and that's when I found out that the alternator wasn't charging....

Hopefully this might be starting to build up a picture for somebody that might see the error of my ways.... ?

gtd2000

Would anybody have a link to an online manual - I used to have a link for one....

Blackerninja

Nearly all of my interior power wasnt working, turned out to be the alternator fuse, the 70 amp or so big grey one.

Possibly shorted something in the alternator system?

KiLLeR2001

You need to ground the damn alternator to the chassis... If its grounded correctly, check the resistance on the thick wire, if its fried it could have enough resistance to not yield a proper recharge voltage.

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gtd2000

Well the part that's confusing me here is that the alternator tested OK at Autozone and I even replaced the 75A fuse with another one from the breakers yard and no dice...

Is there another fuse that I'm over looking that's 70A?

gtd2000

On a positive note, the gas tank was replaced today by a couple of guys that came down from Bradenton.

Cheers to JohhnyBoy up in Orlando for the replacement tank

KiLLeR2001

Were you born in the state of Florida? Cause only that would explain the reason why you can't decipher what I said earlier.

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gtd2000

I'm pretty sure the ability to understand English and being born on Florida are often mutually exclusive

Following your logic process... the grounding of the alternator is common to the function of almost all of the interior electrics - e.g. windows, dome light, indicators, fans etc., etc.?

When I removed and re-installed the alternator I cleaned all of the contacts and removed one of the earth terminals near the strut tower and gave it a good rub down (there's no corrosion anywhere on the car it has to be noted) but everything looked good to be honest.

Is there somewhere that I should be looking specifically for grounding problems with the alternator?

Edit: Cheers in advance

Agamemnon

Are your dummy lights on the cluster coming on at all when you turn the key to the "ON" position?

gtd2000

Nope, no cluster or check lights at all....

When I turn the ignition on, the only thing in the dash binnacle that illuminates is the panel for the LCD clock but the black digits are not displayed...?

Never had any electrical gremlins really apart from a drivers side motor went out back in 2001/02 and about 7 years ago the battery lead started to get a bit funky and the main cable was trimmed down and a new terminal installed.

I'll need to see if I have any pics of that.

Edit: Here's the old pic before it was cleaned up properly - I'm over in CA right now so can't take any current pics.

gtd2000

Well I've been surfing the net and found some guy in Holland with the same problem as mine but in an S13...

So in my case the original 75A fuse looks perfect and the second 75A fuse that I installed looked perfect but the situation did not change...but the problem this guy had was identical - should I try yet another 75A fuse???

gtd2000

Just to clarify - is the mentioned 75A fuse the one in the black fuse box holder on the left of this image?



Or is there another 75A fuse elsewhere?

Agamemnon

If the car is an SE than the fuse that is on the charging circuit is a 100A fuse. Have you put a multimeter on the battery terminals to see if the alt is actually functioning? If the alt is good, and the fuse is good, and and all the grounds are good, then the last culprit is the battery bulb in the gauge cluster. The bulb completes the circuit to the alt to tell it to start charging.

gtd2000

Yeah my car is an SE model.

So I should be looking for a 100A fuse that's blown?

Alternator tested OK at Advance Auto but didn't do a test once reinstalled.

I'm over in CA right now, so will have to relay this info to my GF.....

KiLLeR2001

I'm no expert with S14 wiring, but this most definitely appears to be a false statement. If you have a diagram that displays a burnt or missing bulb able to dictate whether or not to charge the system I'd love to see it. LOL.

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Agamemnon

Refer to pages EL-31 and EL-32 of the FSM. It clearly states that with the ignition in the ON or START position, power is supplied to a 7.5A fuse(#2 in fuse panel) that goes to gauge meter terminal 21 of the charge warning lamp and is then grounded by meter terminal 15. That is then connected to terminal L on the alternator thus activating it.

Agamemnon

Yes. Base models cars use a 75A fuse, SE's use a 100A. Also check for a 7.5A fuse located in the same fuse block. Its labeled "ALT". The other fuse for the charge warning bulb is located in the fuse panel in the driverside kickpanel, right row, second one down.

Alternator tests are hit and miss. Ive seen numerous "good" units still fail or come short of the recommended voltage required for our cars.

KiLLeR2001

If you look at the diagram, you will see that the warning lamp does not dictate whether or not the alternator will work or not. As long as power is supplied from the battery and there is ground, the alternator will produce voltage.

Now if the alternator IC regulator detects that it is not supplying correct voltage, it will send a ground signal to terminal 15 thus completing the circuit to the warning lamp. Having this bulb not working or unplugged will not affect the alternator's performance, it only serves as an indicator to tell the driver the alternator is not working properly.

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gtd2000

I think, following the logic process here, that the lack of power from the alternator is possibly secondary to the original observation where none of the dash lights other than the back light for the clock illuminate?

Does the 100A fuse control the circuit to the dashlights, dome light, power windows, blowers, radio etc.?

These should all come on without the engine running with a charged battery, it is charged as it starts the engine fine and is on a trickle charger to keep it charged.

So when I turn the ignition key and the dash lights don't illuminate this can't be the fault of the alternator working or not surely - that only comes into play when the engine is turning over and is used to charge the battery and supply power to the rest of the vehicle - or that's my understanding?

KiLLeR2001

This is not an alternator issue, you have some power wires that are most likely not hooked up to your (+) battery terminal. The plugs that plug into the red connector need to be joined together with the starter wire and that all needs to be hooked up to the positive terminal.

Check for voltage on the alternator power wire and the alternator plug. If good voltage exists, then make sure you have a ground wire from the body chassis connected to the back of the alternator.

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gtd2000

OK - I've looked into this already - I removed the plug-in wires from the red connector and tried wiring them directly to the battery - no change.

I bought a used (good condition) red connector from a Nissan Maxima at the breakers and now have this installed with the two plug-in wires connected using the standard connectors to the red block also no change.

Can you tell me what the two smaller gauge wires are that go into the red block are for - I assume they have separate functions?

I'll see if my GF can do this but I suspect it'll be something that's going to be a bit of a drama...

Here's a look at the pics taken tonight of the fuse box:





Here are the connectors I took apart at the gas tank before this problem started...



I understand that to get the main 100A fuse out you need to unbolt the fuse box and split it then unbolt the fuse from the holder?

KiLLeR2001

I'm not sure. I don't own an S14 and haven't really looked at the wiring schematics as closely as I have with S13's. But on my S13, there are also two plugs that plug into a connector at the (+) terminal. One plug is the thick 10 gauge wire that goes to the alternator, and the other plug has two wires which I'm pretty sure go to the alternator harness plug.

I would suggest taking a look at the S14 FSM and browsing the charging system diagrams.

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gtd2000

I'm on my laptop right now and had a copy of the FSM on my desktop from memory..you don't have any links to the FSM online do you?

I'm really hoping this is all going to be simply down to the 100A fuse being blown.....

I'll probably end up re-doing the whole battery terminal/cabling arrangement once I get to the bottom of this.

Edit: Found the FSM online

gtd2000

Looks like this is the explanation of the 3 cables to the positive terminal:


1. Starter +VE - (blk/red) Heavy battery cable from Batt +VE to Starter.
2. 12V Sense - (white on S13, yellow on S14) Smaller gauge wire. Connect to Batt +VE too.
3. Charge - (white on S13, blk/red on S14) This is the big lug on the alternator. Connect to Batt +VE

Source: SR20 RHS Engine Wiring - Details

KiLLeR2001

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gtd2000

Having looked at the electrical schematics, I can't see the 3 connectors for the positive connector at all anyway...then again perhaps I can't read the drawings....

gtd2000

Well folks the problem is solved and it's quite a simple fix really.

There was a bit of a red herring with all this talk of a 75A fuse which was pretty close to the truth.

As my car is an SE model it's the blue 100A fuse that causes the symptoms that others experience in the regular non-SE 240SX.

I got my GF to prise open the top of the blue fuse as she couldn't see properly into the fuse. she reported that there was a gap - so the fuse was blown.

I then asked her to get a pointed object and bend the two blown halves together so that they touched. Once this was completed all of the electrics worked so I ordered a couple of new 100A fuses.

Should be here this week sometime and I'll talk her through installing them which might be easier said than done!!!