A/C question.

[Sycostang67]

When I am idling in traffic, my A/C works ok. When I am driving though, it works a lot better, about 20* cooler when driving. Last year my fan clutch was a suspect but I replaced it and nothing changed. I am still running R12 if that matters. Any ideas?

 

[87crewdually]

Without the volume of air the system cannot be as effecient so you will see a difference. For this reason is why most cars nowadays have an electric fan to pull air through even sitting still.

 

[RLDSL]

Put an electric pusher fan on rigged to come on with the ac. Your fan clutch doesn;t lock up till the engine gets REAL hot till then it only draws minimal air through the condenser

 

[Sycostang67]

If I run the fan through a relay, would I be able to trigger it by tapping into the wires on the A/C compressor or do I need to get the signal somewhere else?

 

[SparkandFire]

I would run the relay off the a/c compressor signal. Not only does it only run when the AC does, but, it's also diode protected.

 

[DragRag]

sparksandfire, are you into Torino's? I have had a dozen or more 70' and 71's. Some very rare ones also.

 

[87crewdually]

I'd tap into the pressure switch hot side for a trigger. This way the fan runs continuous even if the compressor is cycling on/off.

 

[Sycostang67]

I'd tap into the pressure switch hot side for a trigger. This way the fan runs continuous even if the compressor is cycling on/off.

Where is that located in the system?

 

[RLDSL]

Where is that located in the system?

The switch on the accumulator . You want to find the cold leg of it when the thing is unplugged and use that for the trigger wire for a standard bosch relay, then run your constant hot from the batt through a circuit breaker to the relay and you're in business

 

[Willie Two]

When I am idling in traffic, my A/C works ok. When I am driving though, it works a lot better, about 20* cooler when driving. Last year my fan clutch was a suspect but I replaced it and nothing changed. I am still running R12 if that matters. Any ideas?

You may be low on R12

 

[Sycostang67]

The switch on the accumulator . You want to find the cold leg of it when the thing is unplugged and use that for the trigger wire for a standard bosch relay, then run your constant hot from the batt through a circuit breaker to the relay and you're in business

I will borrow a fan and see if it helps.

You may be low on R12

I bought an A/C thermometer that came with a pencil type pressure guage for the A/C. I tried to use it but get a different reading each time.

 

[SparkandFire]

sparksandfire, are you into Torino's? I have had a dozen or more 70' and 71's. Some very rare ones also.

I'd love to get my hands on a '70 or '71 one of these days!

I've wanted one of those for a real long time!

 

[RLDSL]

I will borrow a fan and see if it helps.


I bought an A/C thermometer that came with a pencil type pressure guage for the A/C. I tried to use it but get a different reading each time.

It will give a different static reading depending on the ambiant temperature outside. REfrigerant pressure changes with temp.