Is it a 1975 280Z?  Is it fuel-injected?

It could be the power supply to the ECU.  There is a ground wire and a power wire, both at the battery terminals.  The power wire has its own fusible link.  Don't get them backward.

 

Is a 78 model but actually manufactured in late 1977, so the features of the 78 model apply

 @wal280z

THE guru for that type stuff.

I have his upgrade "from the junkyard" Cadillac parts.

How are you Wayne? Long time no speakie. Hope you are good. 

 

  On 3/2/2023 at 9:54 PM, DHA280Z said:

Is a 78 model but actually manufactured in late 1977, so the features of the 78 model apply

Weird that you said Amp light and not Voltmeter.  USA cars from 1976 on had Voltmeters, not Ammeters.  Maybe you meant the Charge lamp in the Voltmeter.

Is it a USA market car?  You didn't say if it has EFI or not either.

The more details the better.  Maybe @EuroDat is out there and can help out in Dutch, if it makes a difference.  No offense intended.

You are right I was referring to the voltmeter gauge and red charge lamp. The Datsun is an USA model with fuel injection

There is a fuse that is on the supply wire to the charge lamp circuit.  Seems like the most likely place to start.

Does the Brake light light up when you turn the key on?  That is the other part of the circuit.

Don't forget to check your grounds too.

Edited March 3, 20232 yr by Zed Head

  On 3/3/2023 at 11:32 PM, Zed Head said:

There is a fuse that is on the supply wire to the charge lamp circuit.  Seems like the most likely place to start.

Does the Brake light light up when you turn the key on?  That is the other part of the circuit.

Don't forget to check your grounds too.

Indeed, there is no brake red light and buzzing (bip-bip-bip) sound doesn’t comes out either 

The voltmeter works but not the Amp light

Is the T plug at the alternator plugged in?  Check for continuity to ground through the bottom leg of the T on the alternator pins if it is.  The alternator is the ground for the two circuits.

Yes the T plug is in. Will check grounds tomorrow, now is wet, cold and dark outside. 🥶 

  On 3/2/2023 at 10:08 PM, siteunseen said:

 @wal280z

THE guru for that type stuff.

I have his upgrade "from the junkyard" Cadillac parts.

How are you Wayne? Long time no speakie. Hope you are good. 

 

Thanks so much for the link! I read through all 7 pages hoping to find somewhere where the fusible link ratings were translated into amps - the previous owner of my 75 280Z has been telling me they are 'fussy'. I'm more than happy to update this & add the H/L relay mod while I'm at it

EDIT - adding the amp rating cross reference link HERE   🙂

Edited March 13, 20232 yr by HusseinHolland

It's been pretty well documented that what is shown as a red link is actually a brown link (they're shown in the FSM) and it is also a lower rating (smaller gauge) than the green link (also in the FSM).  I never looked too closely at that chart in the past but now see that it has a yellow and a pink link.  You won't find those on a Z.  Maybe a ZX but not a Z.  (Sorry Blue 246, no offense intended).  Some of the Z car aftermarket suppliers like thezstore.com have updated their fusible link pages to show it.

Don't forget that fusible links are "slow blow" fuses.  Most automotive fuses are meant to fail quickly.  Good luck.