electrical help - fan, horn, blinkers, temp

[Dr Terry]

Go back to basics first.

You need 4 cables to the battery as a minimum.

1. Thick cable from +ve battery terminal directly to the starter.
2. Thinner cable (6mm) from -ve battery terminal to the alternator output
3. Thick cable from -ve battery terminal directly to a bolt somewhere on the engine on head. From memory, the original V8 earth cable used a bolt at the alternator bracket.
4. Thinner cable (6mm) from -ve battery terminal directly to a good body bolt. I think the original went to a radiator mount bolt or the radiator support panel itself.

The 2 thick (heavy) cables only carry starter motor current, the other 2 carry the current for the other stuff (lights, relays, instruments, heater fan etc.).

As agro71 has said, the coil voltages will vary depending on whether it has points (& whether they're open or closed). If it has electronic ignition &/or a ballast resistor the voltages again will be different.

Dr Terry

[Vombil]

Go back to basics first.

You need 4 cables to the battery as a minimum.

1. Thick cable from +ve battery terminal directly to the starter.
2. Thinner cable (6mm) from -ve battery terminal to the alternator output
3. Thick cable from -ve battery terminal directly to a bolt somewhere on the engine on head. From memory, the original V8 earth cable used a bolt at the alternator bracket.
4. Thinner cable (6mm) from -ve battery terminal directly to a good body bolt. I think the original went to a radiator mount bolt or the radiator support panel itself.

The 2 thick (heavy) cables only carry starter motor current, the other 2 carry the current for the other stuff (lights, relays, instruments, heater fan etc.).

As agro71 has said, the coil voltages will vary depending on whether it has points (& whether they're open or closed). If it has electronic ignition &/or a ballast resistor the voltages again will be different.

Dr Terry

for battert ive got 2 on the -ve and 2 on the +Ve

neg thick to alternator block bolt, neg thinner is to rad support

pos is 1x thick to starter and 1x thinner to alt input? There is a earth?? ( a very thin black wire) that comes out of the back of the alt (separate to thicker input) and runs back towards the starter and into the loom near firewall.

so i have 4. but not a -ve from batt to alt output

[Dr Terry]

[QUOTE=Vombil;99550
pos is 1x thick to starter and 1x thinner to alt input? There is a earth?? ( a very thin black wire) that comes out of the back of the alt (separate to thicker input) and runs back towards the starter and into the loom near firewall.

so i have 4. but not a -ve from batt to alt output[/QUOTE]

That's not quite correct.

The smaller red wire goes from the battery +ve to the alternator OUTPUT.

The alternator has its own earth thru its own metal case.

The very thin black wire that you mention is actually a brown wire & it is not an earth, it is the alternator light wire. It runs back into the harness to the "battery" light light in the instrument cluster.

Dr Terry