It's all about the AC

[Coronet67guy]

Hi Guys. I chose this forum because this is mainly about wiring of the AC. I have a 74 Charger, 400 big block, originally an AC car. When I bought the car all the AC components had been removed from the car, so the next project is getting it all back in. To further muddy the waters my 400 motor is from a later model car, 76-78. I'll be going with a stage 2 system from classic auto air.

https://www.originalair.com/dodge-b...rallel-flow-condenser-r134a-stage-2-big-block

I'm replacing the water pump housing with a 440 source one and using the CVF racing v-belt system for my AC brackets, as well as alternator, power steering, and crank shaft brackets and pulleys. I've purchased a high pressure switch. What else do I need to think about in the way of switches and wiring? Any other issues that you would be worried about if you were doing this job? My mechanic takes care of all the electrical and AC connections, but I like to have everything he needs ready to go when he gets the car. Thanks!!

 

[BLK 68 R/T]

When you say all the a/c components. Is all the inside the car a/c stuff still present? Heater/ac box, controls, ducts, wiring, etc?

 

[451Mopar]

instructions make it sound like you put the thermostat in series with the pressure switch?

 

[Coronet67guy]

When you say all the a/c components. Is all the inside the car a/c stuff still present? Heater/ac box, controls, ducts, wiring, etc?

I believe everything is still in place inside the car, its just under the hood. Possibly it was all removed when they put the new motor in and not put back.

 

[Coronet67guy]

instructions make it sound like you put the thermostat in series with the pressure switch?

If you have a link to good instructions please send. The one in my 74 parts catalog is all wrong, showing the drier up in the passenger side fender well.

 

[BLK 68 R/T]

The wiring on the engine bay side is pretty straight forward. Wire from the inside to the pressure switch, from there out to the compressor. I did a complete system on my 68 charger. Make sure to ground the compressor good. I had an issue with clutch chatter and kick on and off real quick. Ground wire from compressor to battery fixed that. Probably can expect some pulley alignment issues with using aftermarket pulleys and brackets. Also depending on if you are using the original style compressor bracket or a retrofit one the fan may hit the compressor. Really need to just mock up everything you have and see if it will all fit together.

 

[Coronet67guy]

The wiring on the engine bay side is pretty straight forward. Wire from the inside to the pressure switch, from there out to the compressor. I did a complete system on my 68 charger. Make sure to ground the compressor good. I had an issue with clutch chatter and kick on and off real quick. Ground wire from compressor to battery fixed that. Probably can expect some pulley alignment issues with using aftermarket pulleys and brackets. Also depending on if you are using the original style compressor bracket or a retrofit one the fan may hit the compressor. Really need to just mock up everything you have and see if it will all fit together.

Thanks. My mechanic will probably already know this stuff, but is there just the one high pressure switch at the drier? I saw a low pressure switch listed on eBay also but not sure my car needs it. Sounds like the wiring of the compressor is pretty cut and dry.

 

[BLK 68 R/T]

Thanks. My mechanic will probably already know this stuff, but is there just the one high pressure switch at the drier? I saw a low pressure switch listed on eBay also but not sure my car needs it. Sounds like the wiring of the compressor is pretty cut and dry.

Not sure on the low pressure switch since you have all the factory stuff under the dash.

 

[Coronet67guy]

Just kicking this old thread back up instead of starting a new one. I've got the CVF Racing brackets on and went as far as I can go with the AC. Soon I'll take it to have the pressure lines installed, get the wiring done, and charge it up. I guess my main question is am I crazy to do this without pulling the heater box and changing the evaporator, and at least cleaning up and leak testing the heater core? I have no reason to believe it's not original to the car. It's not something I have ever tackled and I know it will add a lot of time and expense to getting AC again in the car.

I also only get the blower to blow air in the AC and Max AC positions. Nothing in the heat, vent, or defrost positions. I can hear the ducts open so I'm assuming this is something in the heater control switch. Anything else this could be? My biggest fear is I spend all this money to get this system charged up and ready to blow cold air and it doesn't work.