Mitchs73

I am currently routing the wiring for my new classic auto air system and I need some advice:

1. For the 12v power lead, is there a way I can tap into the original ac/heater lead on the fusebox? If so, which wire is it and how can I access it?
2. Where can I get a good ground under the dash to connect the 3 ground wires I have for the system? I ran some test locations using a direct hookup the battery and couldnt get a good ground anywhere except directly to the negative terminal.

Thanks a million!

Richard454

I'd just run a power and ground wire to the battery... and be done with it- did that for my buddy in his Vette -he has had no issues.

MAKE sure you use a fuse AT the battery. The ECU likes nice clean power- if you'll note in the instructions to ONLY use a battery to test it- not a battery charges as they are pretty "dirty,"

You can also get a good ground off the bellhousing if you want...

For the switched ignition- you can use the yellow power wire at the radio-as the switched ignition wire doesn't draw much power at all. Using the radio wire- the AC will NOT be on when the starter is engaged- which is what you want.

I'll take the money in small bills-and meet me behind the package store!!!

Zoomin

You can also get pos and ground from the starter.

Richard454

You certainly could- but you'd wanna fuse the hot wire close to the starter terminal- which would make it tough to acess if it blows.

7T1vette

You could wire it to the alternator terminals, as long as the positive power wire has enough capacity for it. Ground for the alternator is via the engine block...no problem there, unless the main chassis-to-engine ground cable is missing. Wherever you connect to positive, you should include a circuit breaker of adequate size for the A/C unit. If you want to be certain the positive connect point has adequate current carrying capability, install a terminal block on the right-side inner fender and run a #8 or #10 wire from it to the positive lug on the starter solenoid. You could also pick up good ground at the engine mount bolt which connects that main chassis-to-engine ground wire. Use the same size of wire for both positive and ground wiring.

Mitchs73

Thank you all for the advice so far. I live in Florida so I'm excitied to finally have working AC. I have a couple more questions:

1. Since the car had factory AC, would it be easier to use the existing harness? Would I get enough clean powerdraw? If so, which wire from the harness is the power lead?
2. Assuming 1 is a no go, if I hook it up directly to the battery with a 25a fuse, would there be a powerdrain? I figure that ill need to turn the a/c off when the car isnt running.

I am trying to keep as much wiring out of the engine bay as possible so I'd like to stay away from the alternator/starter solinoid.

Richard454

Your original AC didn't have any electronics. And a lot of manufactures will not warranty equipment that was not connected to the battery as per their installation requirements. The battery is the best for electronics- the battery not only starts your car but also stabilizes the voltage and is a great filter. You need a filter as the alternator creates AC power which is converted to DC- BUT there is still some AC ripple or noise present in the wire- the battery cleans it up. AND when you turn on the lights- electric fan(s) - the voltage surges as the alternator ramps up for the large current draw- at the battery the voltage doesn't surge near as much-thus stabilizes the voltage. Electronics LIKE this!!!

Running a couple10GU wires up the console to the battery is the easiest- straightforward way to do the job correctly. IIRC the system comes with a circuit breaker- a short wire off the battery to the circuit breaker and then the wire run right to the ECU. Running the ground along side the powerwire is even easier as it doesn't require a fuse or circuit breaker.

The classic air has a not volatile memory- so when you program it- so there is no power draw to keep the memory when the car is off- You won't have any problems with parasitic battery drain.

You can leave it on when you turn off the car- AND using the yellow radio wire (or wiper yellow wire) when you start the car the AC will not be on when the starter is engaged.

Richard

Mitchs73

Thank you Richard. I'll definitely go the battery route here.

I am a bit confused on how the yellow radio wire comes into play here. Do I connect that to the positive power lead as well? Or is that connected somewhere else?

Zoomin

Power is described in two ways: always on, which would be anything connected directly to your battery for example.
The other type is called ignition on, which only supplies power when the key is turned on. This is what the yellow wire is for. An example of this is your radio, which only works when the key is on.

When I mentioned connecting to your starter earlier, I did not mean the solenoid connections, but rather the main power cable that goes from the starter directly to the battery. The ground could connect to the block or frame, whereever is convenient.

7T1vette

I agree with Richard about the battery being the BEST place to get power--especially something with hi-tech electronics in it. If that's what the A/C mfgr requires, that's what you should do.

And, yes, you still need either a circuit breaker or fuse in the positive line[s] going to the A/C unit to protect it and your wiring, should there be any electrical "mishap".

Mitchs73

I understand what youre saying now. Thank you. Forgive me, I am a bit of a novice when it comes to wiring. I know how to setup wiring safely, but I get lost when figuring out what gets hooked up where.

So if I want to run my pos power lead through the battery via ignition on, is that main power cable that goes to the starter the best option? (With a 25amp fuse of course). Or is there a way I can set it up running cable through the console as Richard suggested?

Thank you guys a ton for working with me here.

Gordonm

I have run a Buss bar from the starter lug with a short piece of #6 wire. This gives me plenty of power and enough amperage to run my cooling fans and the VA AC unit for power. I mounted it down low on the passenger side firewall not far from the starter.

Zoomin

Not quite. The main power cable that goes to the starter is "always on", regardless of key position.
Which wire are you talking about? The red wire should go to an "always on" power source and the yellow wire needs to go on "ignition on" source. The only wire that would need run up through the console is the red one, if you want to directly connect to the battery. Personally, I'd hook it to the main power lug on the starter, just because it's less wire running around and you don't have to fish it under the carpet.

Mitchs73

So this classic auto air system has one 12v pos lead and three ground wires. That's it. There isnt a yellow wire which might be why I'm confused. But it sounds like the 12v pos lead needs to go on a ingition on source, correct?

lan240

I am interested in the classic auto air system for my 69 Vert. can you let me know your thoughts on the system and how easy/hard it was to install?

Zoomin

Mitchs73

I'm going to do a whole write up when I have everything installed and I've had a chance to really run and use it. I'm doing a full insulation/sound deadening job on my '73 as well. Florida heat and all.

I chose CAA over VA is for the following reasons:

1. The CAA unit has more evap coils than the VA unit. More coils = more cooling. I like my cars ice cold.
2. The VA evap unit is closed and sealed whereas the CAA evap unit is openable which means it can be serviced.

Otherwise the units are pretty comparable in terms of components such as the blower, compressor, etc. My only complaint so far is that the compressor mount it came with was garbage so I bought a better one off of summit racing for ~$200. Otherwise the hardest part of the install was ripping out the factory ac unit.

Richard454

AND the instructions aren't really clear...I wouldn't assume - I'd be giving them a call!!!

Mitchs73

My problem exactly!!! I called them and they didn't really have a clear answer for me. At this point I'm considering running it through the accessory ign on port on the fuse box with a 20a fuse (I just noticed it said 20a on the instructions).

7T1vette

Power never gets to the compressor until the A/C low side has adequate pressure. If the engine isn't running, that can't happen. I assume that the computer gets its 12 vdc from a 'switched' source, rather than a battery feed. That's the way a Vintage Air system works, also.