410 Air Conditioning

[David C]

To summarise:

The 410 has a single fan relay which is operated by the Otter bimetallic switch in the top of the radiator. According to the wiring diagram the manual switch passes full current and does not operate the relay. Both options, automatic and manual operation are fed from the ignition switch.

The 411 has two relays, one for automatic thermostatic control and another for manual override. The relay for automatic control is fed directly from the battery and the relay for manual control is fed from the ignition switch.

My feeling is that I would rather not have this much current flowing through the ignition switch. I have seen melted switches and wires on early V8s. It's much easier to prevent the smoke coming out than to get it back in.

The ammeter and wiring on the early V8s coped - just - with the original load but as we add more power hungry accessories it is important not to add more load to the ammeter or to the ignition switch. This is easily achieved with relays fed directly from the battery controlled by feeds supplied from the ignition switch but this will not show up on the ammeter. Much better to ditch the ammeter and replace with a voltmeter per 411 which will give a better overall idea of what is going on.