Re: Add-On-Air Conditioning, 54 Cavalier.

Posted by BigKev On 2012/5/14 21:57:05

Sounds like the is an issue with how the 12v alternator is wired up. It should have a "energize" wire that should be switched. Sounds like it is always hot, and that is why it is draining the battery over time.

The 12v alternator bat lead should wired to the 12 battery. Then from the 12v battery there should be a larger fused feed for the A/C system that goes to the switched side of the relay, and on to the A/C setup.

There should also be another smaller fused feed that feed the under dash switch, and then to the trigger terminal on the relay and also the ground terminal of the trigger should be grounded.

Now that covers the basic A/C setup. No you just need another smaller 6v relay that you can use to trigger the energize wire on the alternator, so it can charge the 12 battery regardless is the A/C is active or not.

For that you would take the hot side of the under dash A/C switch and connect to the switched side of the 6v relay, then the other side of switch to the energize wire on the alternator. Then connect the trigger side of that relay to the switched on side of the Ignition switch, and of course connect the trigger ground.

So when the ignition is turned on it activate the 6v relay (6v switching) and supply 12v to the energize circuit on the alternator. That 12v feed is so minimal that the won't hurt 6v relay.

So to recap... the alternator will charge the 12 battery only when the ignition is on. The A/C system uses has its own relay that is for turn that system on or off, and has no bearing on the charging circuit itself. This should keep the battery charged when the car is running (as it does in any normal car). When the ignition is off, it will kill the energize to the Alternator preventing the alternator regulator circuit from draining the battery.