Help:Getting the original AC working

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Jeffs73

Jeffs73

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Hello, I would like to try and see if I could get my AC going again. It is in a 1973 Plymouth Duster. All the original components are there and have never been tampered with. It is very complete and all componets look very good. When I move the switches though nothing happens. And I really know nothing about ac. At first I didn't have power to the fuse for the ac blower motor but know I have power. It still doesn't kick on. I am not sure what to check. A little guidance would help. Do I need the ac belt on for the blower to kick on? Where do I need to check for power? Thanks
 
The switch may be bad,check power going to it with ignition in run position.
 
Yes the belt needs to be on for the A/C to work. There is a low pressure contact switch that is usually on the A/C dryer. It's a two wire pigtail that plugs onto a pressure switch that prevents the compressor from engaging if the system is empty or low on Freon. This prevents you from doing damage to the system. If you've never worked on A/C systems, you really need to get someone to help you that has this knowledge.
 
I just wanted to ask the common things I could check. If there is something major with the system then it will be removed completely. I just like to know what to check for with the switch and maybe the compressor to check for power.
 
Does the blower motor run at all ? You do have heat right ?
What did you find wrong or what have you done to get power at some fuse ?
 
Now when I turn the switch to ac and max ac and either high or low I get very weak cold air coming out the vents. What does this mean?
 
RedFish said:
Does the blower motor run at all ? You do have heat right ?
What did you find wrong or what have you done to get power at some fuse ?
Click to expand...

I don't have the heater hoses hooked up. I changed the ignition switch to get power to my fuses.
 
I still don't know if the blower runs with the heat mode at various speeds, or if the vents change positions.
Just trying to get the basics sorted here.
 
Roy nailed why the compressor won't kick on, and by "weak" do you mean very little air, or not cold air?
If it's very little air, you probably have a vent door that is not opening when the AC comes on.
If it blows ok but is not cold, then it needs serviced and recharged.
All this assumes that the compressor is now activating when you turn it on, and the blower works.

If the comp seems to work then a good recharge and some system sealer would be the next step.
In order for them to work decent they need to be vacuumed down and then refilled.
Some people get away with not doing the vac down part, but thier AC does not work as well as it could if it was done right.
 
If the blower is working but only at low speed it could be a bad fan switch as these are known to over heat and burn out. Or it could be the blower motor resistor. It is located in the blower housing on the top, (behind the glove box) there is a pigtail that plugs in to it with 3-4 wires, I forget now.
 
Sorry for being stupid here but I'm not really sure if the compressor is turning on. Not really sure if the blower is either. I have just very light air coming out of the vents. It is some what cold. It does blow a little more when put on high and less on low so I think that works
 
If the compressor is working, the center part will be spinning at the same rate as the pulley with the belts on it.
 
My compressor is not kicking on but my fan works. It blows just air out. What does this mean with the compressor?
 
SGBARRACUDA said:
If the blower is working but only at low speed it could be a bad fan switch as these are known to over heat and burn out. Or it could be the blower motor resistor. It is located in the blower housing on the top, (behind the glove box) there is a pigtail that plugs in to it with 3-4 wires, I forget now.
Click to expand...

2 and a separate ground Roy. :D
On mine any way.
 
Means the system is more than likely empty or very low of Freon. I'm not surprised, they will leak out over time especially if they are not used for a long period of time. I think your going to need someone with A/C knowledge and a set of A/C gauges.
 
really, as has already been pointed out..... you need to find someone close to you to help you in person.... its awfull hard to repair something over the internet, especially if YOU don't at least have a basic understanding of how it works.... no offense intended
 
Didn't you tell me you have a shop manual? You need to spend some time reading it.

It's likely low or empty of freon. Most likely, unless the car has been driven and mainained, it's the old R-12, unlikely but may have been converted to R-134

Could be something in the switch/ wiring is not activating the compressor, something wrong with the temp switch, or the low pressure switch is open.

Find the low pressure switch in the system, pull the connector, and with the key "in run" turn heater and temp switch for AC operation. Then check for power at both terminals of the harness connector at the low press. switch.
 
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