I recently changed the head gasket on my motor and so had most of the big items in the engine bay removed. 72 240z.

On getting it going again I broke down due to a flat battery and can remember the turn signals were still working at the time. At this point alternator wasn't charging anymore I guess.

I charged the car up and drove at night where it rained heavily and almost broke down again due to flat battery and from then on my turn signals have stopped also.

I'm really bad with electricals and have no idea where to start looking. I'm thinking it's probably best to get help on finding out why the alt has stopped charging.

The alternator is only 1yr old and is the old external regulator type. As I initially thought it was faulty I've changed it now to the 280zx 70amp (internal regulator) one but still theres no charge with Voltage reading only 12.9V.

Should I start by testing if there is power coming out of the alternator? I have an amp & volt meter.

Thanks.

First, when you changed to the internally regulated alternator, did you remove the voltage regulator and put in the jumpers (http://www.zhome.com/Care/Altwire.htm) or MSA/Dave Irwin plug for the internally regulated alternator to work?

Edit: I forgot to add, once you get your car charging properly, diagnose your turn signals using this link as a guide.

Edited April 6, 201311 yr by SteveJ

The alternator is only 1yr old and is the old external regulator type. As I initially thought it was faulty I've changed it now to the 280zx 70amp (internal regulator) one but still theres no charge with Voltage reading only 12.9V.

Your dash ammeter will give a good indication of whether or not the alternator is charging. + means charging, - means discharging (running off of battery power). This would be while the engine is running, when the key is off it should be in the middle.

Car batteries don't like to be fully discharged, it's not good for them. It's also not good for the alternator to charge a completely dead battery. You might have a bad battery damaging your alternators. And, as Steve implies, if you haven't rewired the car for the internally regulated alternator things won't work right.

Also, for the record, the ZX alternator is probably 60 amps, not 70. The 280ZXT's (turbos) came with 70 amp alternators but they're not available anymore. The parts stores replace them with 60 amp alts.

If you're no good with wiring, and find that your battery is bad, you might be best off having the old external reg alternator tested and, if it's good, getting a new external regulator. One option.

It appears your z was out of commission for a while with the headgasket change. I would take the old and new alternators and regulator down to your local parts store and have them tested.

If they say you have a good working set, check the large white and white/red wires at the connectors in the wire bundle on the passenger side of the of the foot well.

After 43 years, I found mine to be quite corroded. Tracing these wires in the wiring diagrams show they are connected to everything!

First, when you changed to the internally regulated alternator, did you remove the voltage regulator and put in the jumpers (http://www.zhome.com/Care/Altwire.htm) or MSA/Dave Irwin plug for the internally regulated alternator to work?

Edit: I forgot to add, once you get your car charging properly, diagnose your turn signals using this link as a guide.

Yes I also got the plug with the diode so the alternator is charging now. Seems to read a lot higher as the revs climb. Got a reading of 14.5V when I gave the throttle a rev.

Looks like my brake lights are out too.....on both sides. It's so annoying. Don't think I'll make it to a track day this next sat with this issue.

I used that awesome diagram SteveJ but didn't get very far. There was not interlink fuse from the battery to the starter motor and no white wire going into the harness.

I found the flasher relay but wasn't sure how to test it.

There HAS to be a wire going from the battery to the starter. Then there should be a fusible link wire between the starter and the wiring harness.

The only way you don't have wiring like I described is if someone hacked/replaced the wiring harness or if you don't have a 240Z.

By the way, no brake lights and no turn signal point the hazard switch as the most likely culprit.

There HAS to be a wire going from the battery to the starter. Then there should be a fusible link wire between the starter and the wiring harness.

The only way you don't have wiring like I described is if someone hacked/replaced the wiring harness or if you don't have a 240Z.

By the way, no brake lights and no turn signal point the hazard switch as the most likely culprit.

Yes there is a thick red wire going from the battery to the positive terminal of the starter but from the starter terminal there is just another wire that goes to the harness. No fuse on that wire?

Also I've read many places refer to hazard light switch but my 72 Australian 240z never had hazards as far as I know. Is this possible?

Edited April 8, 201311 yr by MKI4EVA

Yes there is a thick red wire going from the battery to the positive terminal of the starter but from the starter terminal there is just another wire that goes to the harness. No fuse on that wire?

It's not a fuse. It's a fusible link. Look here to see what I am talking about. It's the part that looks like a piece of wire in the first listing.

Also I've read many places refer to hazard light switch but my 72 Australian 240z never had hazards as far as I know. Is this possible?

I apologize. I didn't realize you drove on the wrong side of the road. While the FSM on XenonS30.com is oriented to the North American market, it does have a wiring diagram for non-North American cars. The hazard switch on that one is a little different. The hazard switch should be between the steering wheel and the center stack on the dash. Just look at the placement on the North American cars and do a mirror image. It should be in about that place. You may need to ask another Aussie about that.

I think the car is holding to my word that I would work out the wiring of the dash once I rebuilt the motor.

ah well looks like the planned track day this sat will have to wait. I'll come back to you once I get a few hours to work on it. So hard during weekends with a little one and long hrs at work.

Tested all the fuses they all seam to be fine. Not even sure what I'm meant to be looking for besides seems a mess of wires.

Can someone tell me how I'm meant to test for an earth wire and positive wire using a multimeter? I know how to test for continuity now and obviously voltage......

A voltmeter will read 12VDC from a positive wire to earth. Most circuits in the Z are wired as positive, fuse, switch, load, earth. You have to make sure that switches are closed and fuses are good for measurements.

For testing earth wires, you can measure resistance from the downstream side of the load to the chassis. Also, touch your leads firmly together to get an idea of the internal resistance of your meter. Subtract the internal resistance from what you measured in the wiring. If it's more that a few tenths of an ohm, then you will need to inspect the harness and the contact point between the wire and chassis.

For the wiring, I think BE-4 should be close if not exact for your car (except for any mistakes made by the documentation team for Nissan). In that wiring drawing, the power for the hazard lights and brake lights come off the same fuse. The brake light circuit does not go through the hazard lights as it does on the North American 240Zs, but the turn signal power does.

There is a 20A fuse in the fusebox for the brake lights/hazard lights. There is a green/yellow wire attached to that fuse. It should be the fuse on the lower left where the cover is marked STOP. From the fuse, the green/yellow wire goes to the brake light switch at the pedal, while a blue/white wire branches off to the hazard flasher. From the brake light switch, another green/yellow wire goes back to the brake lights.

thank you for being so kind and patient with a wiring newb.