Hi all, 78, Wiring the VA and in the instruction it states to run the violet wire to the fuse block and wire to a 12 volt key on power sources. I figured I would just splice the violet wire to the brown wire and should be good to go. My problem is the part of the harness shown below does not have a brown wire that goes directly to the fuse block. I am at the point I am thinking it might be easier to remove the fuse block to find the brown wire. This is were I get nervous, I can remove the block, 2 bolts, but I believe I will have to remove the tape which binds all the wires. Need advice/help when it comes to the electrical. Also, this has an LS6 and I will be installing Dakota Digital gauges which I have at the ready. So I am thinking I may have to remove the take to remove some the wires which are no longer required for DD. Thanks in advance. Bill

See on your drawing C125? C = Connector
That connector is on the Drivers Side behind console side cover near cig lighter.
That is a single Male-F/M connector where the original function control switch was getting it's power from.
Split that connector and use the main dash harness side for your violet wire. It is switched power and is fused 25 AMPS...
No splicing no Bubba....
That is where I would tap into if it were me...

The entire temp control device gets replaced. Since I have an LS 6 from an 01 Z06, the heat/blower/AC harness is removed. That's why I am thinking about splicing into the brown wire at the fuse block.

I understand that...To remove the original HVAC controls all you needed to do is remove vacuum manifold, remove HOT/COLD cable and un-plug C125.
And of course fan speed control connector
Brown Wire Circuit #50 and C125 Dash Harness Side terminates at the fuse box.
It's all right there waiting for that Violet wire...lol

Thanks, but the connector is no longer in the car. It is part of the heater/AC harness. That harness connects to additional harness which hooks up to the starter. I can not run the violet wire to it.

The Air Conditioning Harness is separate from the Main Dash Harness I agree.
But the Main Dash Harness had the Brown wire Circuit #50 for a factory A/C or Non A/C optioned car.
It was just part of the Main Dash Harness.
Now, that doesn't mean someone at some point didn't cut it out of the Main Dash Harness?
Here is the location of Circuit #50 Brown Wire on a 77, same as your 78...

I might be misunderstanding your goal, so if my thought below is too basic, please take no offense.

The violet wire is just a relay trigger, so it will draw very little current.
It doesn't have to use any of the wiring related to the previous HVAC system, any keyed 12v source will work. I would run it to whatever is most easily accessible.

This what I was trying to determine. Thanks, I'll check it out tonight and let you know.

Hi Luke, I agree with you, I figured it would be wise to use the AC/heater fuse since the old harness/system is no longer installed. At least that was my thinking.