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Have you updated your wiring, including fuse block? If not, I'd recommend using a separate fuse block like THIS
This connects to the battery/starter like we've been discussing for clean power, and it also connects to your existing fuse block but draws minimal amps from there. Another advantage is that it will allow for growth to handle stereo or electric fuel pump without running separate leads to the battery.
Here's a link to the instructions for the new fuse panel. Link
The yellow wire on the fuse block goes to your accessory on your old block
The red wire runs to the starter/battery
Orange runs to the red/white on the ac unit
Black to ground
Have you updated your wiring, including fuse block? If not, I'd recommend using a separate fuse block like THIS
This connects to the battery/starter like we've been discussing for clean power, and it also connects to your existing fuse block but draws minimal amps from there. Another advantage is that it will allow for growth to handle stereo or electric fuel pump without running separate leads to the battery.
Here's a link to the instructions for the new fuse panel. Link
The yellow wire on the fuse block goes to your accessory on your old block
The red wire runs to the starter/battery
Orange runs to the red/white on the ac unit
Black to ground
The dash harness with the fuse box was replaced recently by one of the previous owners. Looks like a Lectric Limited replacement.
This looks exactly like what I'm looking for! Thank you! I'm gonna order one of these today. Updates to come.
Have you updated your wiring, including fuse block? If not, I'd recommend using a separate fuse block like THIS
This connects to the battery/starter like we've been discussing for clean power, and it also connects to your existing fuse block but draws minimal amps from there. Another advantage is that it will allow for growth to handle stereo or electric fuel pump without running separate leads to the battery.
Here's a link to the instructions for the new fuse panel. Link
The yellow wire on the fuse block goes to your accessory on your old block
The red wire runs to the starter/battery
Orange runs to the red/white on the ac unit
Black to ground
Yep- that will do the trick!!!
I've found a more compact one that I have used in numerous applications-and it's expandable- I'm getting them for about $8- plus a good Bosch or Tyco relay for another $10.
To answer your questions:
1. I powered my hot rod a/c from the former ventilation system power approximately a dozen years ago and it runs just fine.
2. I use the rod support bolt down by the radio, on the passenger side, as a common ground. I also ran a lead from there back to the battery negative-- to ensure everything ground nicely.
Originally Posted by 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.
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.
I definitely think the switched source is the way to go and Vintage Air got it right. My issue is that this Classic Auto Air unit only has one 12v pos lead for its wiring strategy. If I hook it up directly to the battery, i'll still be able to run the blower motor with the car turned off. In the interest of avoiding powerdraw from any part of the evap unit, I think the extra fuse box with the relay connected to the accessory port is the best solution here. Hopefully this thread is useful for anyone going through the same issue.
To answer your questions:
1. I powered my hot rod a/c from the former ventilation system power approximately a dozen years ago and it runs just fine.
2. I use the rod support bolt down by the radio, on the passenger side, as a common ground. I also ran a lead from there back to the battery negative-- to ensure everything ground nicely.
Good idea on running a ground wire from the negative battery terminal. I want this to run as cleanly and safely as possible.
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.
Unfortunately the Vintage Air piece is not as easy to wire as the Classic Air.... It has several ignition AND battery connections...
UNFORTUNATELY the ECU draws about 100mA while sitting- But to do the Classic Air correctly - would require a switched/relay battery source. So both aren't really wired optimally...
I've got a Vintage Air in my restomod 71-
Vintage Air specifies to run the ground to the battery
Quick update. I just installed the fuse box that Zoomin suggested last weekend. I'm going to upload pictures of my install this weekend and update you on how its working. I have the entire interior of the car our right now for insulation and new carpet so its been a crazy past couple months. Very excited!
Okay. Here are some pictures of the new fuse box. I am using the Jegs one that Zoomin suggested:
Still some cleanup and organization to do in the engine compartment. After I removed the original AC system, it left me plenty of room in the engine compartment. This looked like a decently convenient place to mount the fuse box so it has easy access.
I routed two 10 gauge wires, one 12v positive, one ground, from the battery compartment. I routed it through the side door sill where the rear wiring harness and antenna is. I hooked up the 12v pos to the fuse box and left the ground to use for the AC system. I used the wire for the ground on the fuse box and wired it to the frame.
I drilled a small hole in front of the compartment and hid the wire under the carpet.
I wired the yellow wire to the IGN accessory spot on the original fuse box. I then wired the orange wire to the positive lead on the AC system. I then took my 10 gauge ground from the battery and attached it to the three ground wires for the AC system. The other two accessory wires I wrapped up and hid behind the evaporator unit for any possible future accessories.
I have not had a chance to test this out yet as I am still putting my interior back together. But I will post an update when I start it up and see how it works. Thank you all again for your help to solve this wiring issue
Unfortunately the Vintage Air piece is not as easy to wire as the Classic Air.... It has several ignition AND battery connections...
UNFORTUNATELY the ECU draws about 100mA while sitting- But to do the Classic Air correctly - would require a switched/relay battery source. So both aren't really wired optimally...
I've got a Vintage Air in my restomod 71-
Vintage Air specifies to run the ground to the battery
The Vintage Air systems only use three connections to the battery, One for the main +12v power wire and two white wire grounds, In addition to this the violet wire will tap into a key "on" source (typically the ign. switch or fuse panel) When the ECU is not active expect an apx .3 MA draw, any more than .5 MA should be investigated through continuity checks to reveal the culprit. 100 MA is not the nominal value.
09-08-2018, 11:12 PM
