It's easy if you are replacing the C40 Gen with a similar output Alternator. The wiring changes can all be done at the Volt Reg.
If you are upgrading the Alternator to something with a lot more output then new wiring will need to be run.
If the car is positive earth the battery connections will need to be reversed as the alternator is negative earth. Check this out first. Cars with C40 gens were usually positive earth unless somebody has changed it previously. Usually to fit modern radio etc.
1. If you replace the C40 Gen (22 Amp) with a 15ACR (Internal Reg 28? Amp output)
Disconnect battery. Reverse earth connection if necessary. See above.
Disconnect all wires at Volt Reg.
A1 terminal wires are Brown with Blue trace and go to Ign Sw and Light Sw
A terminal is Brown wire and goes to battery terminal on starter solenoid.
D terminal has 2 Brown with Yellow trace wires. One thick and one thin. The thick one is the Gen output cable and the thin one goes to the IGN warning light.
F terminal has a Brown wire with a green trace. This goes to Gen field terminal.
E terminal has a Black wire that goes to a body earth and is not needed. (It provides an earth for the coils in the Volt Reg) This can be left unconnected.
Connect the wires from A1, A and the thick wire from terminal D together. This connects the output wire to the battery via the starter solenoid terminal and the wires to the IGN sw and the Light sw together.
Connect the thin wire from terminal D to the thin wire from terminal F. This connects the IGN warning light.
At the Alternator connect the thick Brown wire with the Yellow trace to the output terminal and connect the thin Brown wire with green trace to the IND or F terminal.
Insulate all joins and check all wiring again to make sure your connections are correct.
Connect battery (check polarity) and start engine and you should have a functioning Alternator and an IGN light that works.
If you are upgrading to a higher output alternator you will need to run new heavy wiring (say 8mm) for a 55 amp alternator. The thicker the better.
Connect the IGN warning light wiring as above.
Run a new heavy wire from the alternator output terminal to the battery terminal on the starter solenoid. Connect the wires from terminal A1 and A together but don't connect the thick Brown/Yellow wire from terminal D. This new wire replaces the thick Brown wire with Yellow trace from terminal D to the gen output terminal.
(Note some alternators have a third terminal marked something like AUX, SIG or SEN. This is used on newer cars to stop heavy electrical consumers like aircon from operating until the engine is running. This can be ignored.)
If you plan to put in powerful driving lights or other stuff such as ICE then the IGN Sw and the wiring to the IGN sw or Light sw won't be able to carry all the current so you will have to wire extra equipment direct from the battery terminal at the starter solenoid and use relays to control this extra equipment.
Again check all wiring and if in doubt seek professional advice. The usual disclaimers apply.
Edit: added battery polarity info.
This will give you a start.
RonR
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