1975 280Z Using Voltage Regulator Wiring (L terminal?) To Add Charge Indicator Lamp

[HusseinHolland]

So, a little background. For my AC system control relay, I need a signal that ties into the charging circuit (D+61). On a Volvo, this would travel to the ground side of the idiot light, and ground through the alternator (D+61 terminal) when the engine is not running. 

 

As far as I can tell, there is no way to wire this to the alternator, as it doesn't have a equivalent connection

75 280Z

 

Volvo alternator, has an additional diode pack. I don't even know if using a later internally regulated Datsun alternator would fit the bill.

 

I read in another thread (can't quote it here) @SteveJ - That the L terminal of the V reg would serve to provide the charge indicator lamp circuit I need

The 1975 wiring diagram shows a wire connected to the L terminal, but it also shows a voltmeter, so I'm assuming that is an error

 

77 color diagram shows the wiring through to the voltmeter & charge indicator lamp

 

75 diagram - The wiring diagrams I have show a Blue or a Grey connected to the harness side of this. Following it through, it seems to go to the Interlock Relay (which my car doesn't have)

   

FSM shows a W/R wire connected to the L terminal though. 

 

 

 

So, to get to the point, does the '75 voltage regulator in fact have that L terminal & internal circuit that I could utilize? 

 

 

Edited September 29, 2023 by HusseinHolland

[SteveJ]

Here is the deal. As far as I'm concerned, there are gaps between the documentation and reality for the 75. On page EE-14, the manual shows a charge light. Since I've never owned or really worked on a 75, I can't tell if it exists. The 75 should still have an ammeter as far as I know. I don't have a full 75 FSM, so I don't have the BE section to cross-check anything. The parts manual shows an ammeter for the 75. So where would the charge light be? I don't know.

[HusseinHolland]

Thanks Steve - I have the 75 FSM (original hardcopy). It matches the online copy that I have, besides the glitches from scanning

There is no charge lamp on my 4/75 280Z. I do have the ammeter . Manual shows an interlock relay, but I don't have that either.

 

EDIT - when the rain stops, hopefully Sunday - I'll look at the actual harness plug & see if I can wire a test lamp to the L circuit. Should be easy enough to determine from there if it will suit my needs. Thank you for pointing out the L terminal in the other thread.

 

from page EE-14:

 

EDIT  -lookng through my earlier pics - I have an empty spot in the v/reg harness for the L terminal 

EDIT - thinking about the actual lamp - I can repurpose the non-functional low fuel indicator. I'll cut the Bl/Y wire back in the harness & connect that to the L terminal & Blk/Wh wire at my AC relay.

I've taken a Volvo seat belt warning lamp & sanded off the symbol, so I can fit that in the console for the charge indicator lamp

 

 

Edited September 30, 2023 by HusseinHolland

[HusseinHolland]

wired my relay feed to the L terminal via a new charge indicator bulb. Circuit works exactly as @SteveJ described. 

repurposed rear defogger lamp for charge indicator

Bulb holder w/spade terminals

Edited October 6, 2023 by HusseinHolland

[HusseinHolland]

fitted Charge Lamp