I have all of the wires identified to wire the vintage air kit in my 69 coupe but have a question on a few wires. Both the evaporator and electric fan have a wire to connect to a “key on” power source. Can I connect them both to the same ignition wire under the dash? See pic below. I read on another post to connect to either the orange or brown wire in the ignition switch harness

The electric fan also has a second power wire to connect to a 12v source. I found what appears to be a positive wire block on the driver side fender well. The alternator appears to connect here. Can I connect it here or should I run it all the way to the battery?Thoughts?



Source for electric fan 12v power source

Electric fan wire diagram. Red wire to 12v source. Blue to “key on” power

Ignition switch diagram. Connect evaporator and electric fan “key on” power to orange or brown wire.



Ignition switch wires. See orange and brown wire.

 

Personally I tend to stay away from doing anything with the direct ignition switch wires/connectors themselves. I want that switch and wires to stay in a perfect state so when Im driving down the road nothing comes apart.

EVAP Key on power wire Violet
My car is a 69 as well. Why not re-purpose the original heater Fan wires/connector at the connector in the console? I am not a fan of leaving disconnected wires with power in the dash or console anyway. Its a the black connector on the heater switch shaped like a pyramid and has 6 ports and only populated with 4 wires. The Brown wire is the source power for the original heater fan and is fused at the fuse panel for 25A (its actually one of the 2 brown wires at your IGN switch just out in the console). I used that as my key on power for the evaporator. No wires to run and it eliminates a live disconnected wire in the console.

Fan relay pick wire
Now.. your fan relay IGN/ACC power source (doesnt have a fuse on it) that is to pick the relay (turns the relay on with the key) so it has very little power consumption needs. I ran that to the ACC power tap port on my fuse panel. SAME PLACE GM would have run the factory AC harness to.

You AUX fan Power lead (with the fuse holder) from relay to battery pwr.
is the load leg of the relay and needs pretty heavy power from the battery. Your horn relay (you pictured on the fender) is an original source for factory options (power window harness RED to 40amp circuit breaker, Factory AC harness RED 30 amp fuse holder ). I dont see many wires on your horn relay but the pictures is not optimal. Lot of guys have success running things to the horn relay so LONG as its not TOO much power. The ALT feeds it (big RED 10awg wire at horn relay buss) then the other heavy RED 10 awg coming off the horn relay goes down to a fusible link down at the starter solenoid with the battery terminal lug (how the ALT charges the battery). So the horn relay buss bar should be capable of running your AUX fan load leg but I dont know what options you have already connected to it. Get a better picture of it. Also, get that paint off of the bus bar itself you want shinny clean metal on the buss bar. Running too much off the horn relay buss will cook the fusible link down at the starter. (The horn relay also has a Black / Orange wires tied together and connected on the buss bar.. that has fusible links coming off the heavy RED is what feeds your firewall bulkhead conn. then onto the Headlamp switch and IGN switch and left side of the fuse panel). The IGN switch then feeds the right side of the fuse panel.

heater control valve (why not re-purpose what you already have in the car)
I also used the Orange wire from the heater switch to power my heater control valve. There are 2 orange wires that come of that heater switch wire one goes to the bulkhead connector an out to the original Fan motor connector the other goes to the heater resistor connector. Well those are now dead just trace it out and connect one end to the green wire from the Evap harness and use the other end that used to go to the fan motor on the firewall to power the heater control valve (NO wires to run outside). I also repurposed the original fan motor ground to ground my heater control valve, again the original wires are right there.

Not sure how similar our vintage air wiring is... so providing mine so you see what I had for comparison.

 

Great advice. Thank you.

heater control valve:
I ran the heater control valve wire through the firewall in the same hole as one of the evaporator refrigeration lines. I connected the ground to the top of the wiper motor case which is the ground for the wiper motor.

Evaporator ignition switch:
didnt think of the unused fan motor wire. Here is a pic of a the heater control harness. This will be unused correct? Tap in to the brown wire for the evaporator ignition switch



Fan/heater wire harness

fan “key on” wire:
here is a pic of my fuse block. I have 2 open ports. One is IGN and one is ACC. connect to ACC correct? What is the IGN port used for? I also will be installing a stereo amplifier and need a key in connection. Does IGN and ACC power up the same way?





electric fan wiring:
I will get a better pic of the horn relay and clean up the connectors. This would be a convenient place to wire the power wire to the fan. Do I need to add an in line fuse?

evaporator power and grounds:
I noticed in your diagram you made some notes on how you wired the power wire and grounds. Did you not connect them directly to the battery terminals on the battery post?

 

(I ran a junction block which has more studs or longer studs so that I could wire my electronic stuff to one site on the firewall and then ran a 6 awg from that junction block down to the starter solenoid battery lug because the starter lug is just too short and far away and by the exhaust (to put 3 fans relays load wires, 2 electric headlight motor relays load wires and a vacuum pump relay load wire to).

I like more ground in this car ... but dont want to run wires to the battery as it is not necessary as long as your wires are heavy and good I used 0 AWG battery cables. Ultimately the ground comes to the engine block and the frame of the car. I have multiple grounds i added to the frame from the engine and the bird cage and a heavy lug welded to the frame for the battery ground.

I hope this helps and makes sense... its a lot but i did all this so i knew how it all worked. I tried to proofread everything but I am working and trying to do this at the same time. Remember I'm just some guy typing on a keyboard across the internet somewhere. Proof this all out for yourself so it makes sense and that i didnt misstate something. Going from old memory too.

 

You want to use the ACC at the fusebox- otherwise when you run the starter the AC will be on- you want just the needed things on when the starter is engaged....Like the radio and wipers will not run when the starter is engaged.

I would go to the extra trouble of spending less $50 and updating where you connect the FANS - AC- upgraded alternator. The OEM system was not designed for this amount of current draw...

I don't know if you have upgraded your alternator- if not you might have charging issues- especially running AC and idling.

Using the diagram- the cars electrical system will be protected- DO not connect the factory charge wire to the alternator- It can't handle the higher output alternator and won't be protected correctly.

 

Richard

I don't know if he needs to upgrade the electrical system on this one? He not adding high amp dual cooling fans.

Hes just installing vintage air and adding a small AUX pusher to his condenser. In reality all he is really doing over a stock type car is adding a small pusher since these cars did come with AC.

 

On a 69 without AC or TI- the stock alternator would be the 42A.

The 42A are what I call an "OGD" rating- as On a Good Day it might put out 42 A and that would be at about 1500-1800RPM and not at 180ºF.

So at idle- it might be good for 25-30A. Barely enough to keep up when the AC is running- headlights on you will start to wipe out the battery.

 

my car does not have the original Alternator.

 

But just a guess- it would be well worth the effort to upgrade the wiring as well-

I like the Blue Sea marine stuff- good quality-

 

I forgot the standard alt was 42A I keep mixing It up for the 61A that the AC cars had.

Good points txs Richard.

 

what wiring should I replace? The alternator power wire?

 

Here is a pic of my horn relay. I cleaned it up and repaired a broken wire. It was a small black wire in the pic with the red arrow

I decided I will connect the power wire from the fan to the alternator power lug. Any concerns there?

 

Just sayin-


The terminals might be clean- but the wire is over 50 years old- and to me doesn't look in that great of shape at the alternator stud.

I do not know the output of that alternator- like I said if it's the 42 amp - it will work marginally at best- it hot weather- running the AC at idle- just a guess, you will have trouble starting the car.

The battery is a bank account- the alternator is your income...when you spend more than you make- you'll drain your bank account.

I also do not know the current draw of the fan- when it (fan) starts up- it will put an extremely high load on the alternator- it might work for a while eventually it'll kill the alternator.

Think of paying your mortgage with your paycheck versus using your bank account- that's why I recommend getting your power from the battery- or at least closer to it.

When these cars were built- they (engineers) had no idea that someone would own them for more than 7 years- much less add some big current draw items on the car.

The original question-

You can certainly wire to the alternator stud-I don't recommend it- but make sure you fuse it there- as it will not be protected by the fusible link(s)

Richard

 

The next question asked should be, how far are you willing to go?
If this is a DRIVER, I would up the electrical a tad before adding an electric fan for the radiator later?
Is this A/C the only modification planned?
I can tell you from the 73 I am working on the wiring is just above Model A Ford level.

 

I like that, but would do #4 from alternator to Term block to starter. #8 fusable at starter. Feed that existing horn relay off a third fuse. Done
Leave the shunt wire. I have a 73 schematic coming.(disclaimer).

 

I don’t foresee adding dual electric fans as long As the OEM radiator is cooling sufficiently. So I should add a bus bar and connect the fan power wire to it and run it to the starter for power?

 

I have a schematic coming, so unless I stare at it a moment, I cannot answer that accurately.
I never liked the horn /relay/ buss bar design.

 

Another question. Are there any ground locations in the nose of the car? I know there is a ground on the radiator frame but it already has 3 wires on it.

 

Hey Jeff-

Here's a 73- correct a Model T wiring harness is swap-able!!! I have a 73 as well!!!

http://www.keystonestatecorvetteclub...tte%201973.pdf

I look at it -sort of like a sub-panel- let the OEM stuff alone and add the aftermarket separately...

 

Yup.