Idler Solenoid for air conditioning

[mpro69rr]

1969 RR 383 with classic auto air. I bought an idler solenoid because when I turn my air conditioner on, the idle goes down. Do I wire this to the wire going to the compressor? It says to wire it to a switched 12v but I only want it to go on when the air is on?

Thanks!

 

[Gold Rush]

Yes that is about the most convenient location to pick up the power you are wanting. If you are concerned about overloading that circuit, you could use that compressor power line to trigger a relay that would then feed 12V to the solenoid.

I don't know if the fuse protecting the compressor line will carry the extra load. One way to find out. If it pops the fuse then go the relay route.

 

[pnora]

My self I do not think you need it. Does your compressor clutch cycle or does it run all the time? Reason is the solenoid may not be strong enough to open the throttle. Some will hold the throttle open only if the pedal is stepped on and the tension is released then the solenoid can pop out. Thats why I asked if the compressor runs all the time or cycles.

 

[Gold Rush]

My self I do not think you need it. Does your compressor clutch cycle or does it run all the time? Reason is the solenoid may not be strong enough to open the throttle. Some will hold the throttle open only if the pedal is stepped on and the tension is released then the solenoid can pop out. Thats why I asked if the compressor runs all the time or cycles.

OP says when he activated a/c the idle drops. One would think that means the compressor only runs with a/c "ON"

You are correct in that most solenoids do not have the power to press the accelerator but I've never seen one not hold once allowed to activate when the engine comes off idle.

 

[pnora]

OP says when he activated a/c the idle drops. One would think that means the compressor only runs with a/c "ON"

You are correct in that most solenoids do not have the power to press the accelerator but I've never seen one not hold once allowed to activate when the engine comes off idle.

He needs to clarify if it cycles or not. If stock he should be fine. If it has an updated or aftermarket system it could cycle. Knowing the correct answer would help in deciding how to power the system.

 

[YY1]

If you bought one that's specifically marketed as a "fast idle" solenoid, it should be fine.

I had trouble finding one that wasn't actually designed as a "throttle stop" solenoid meant for momentary use instead of continuous use.

I did find one that was marketed as a throttle stop, but was the same design as a fast idle.

Edelbrock and Holley both sell one but it is well over $100.

The one I found is the same part, but only $45.

 

[YY1]

When "AC" is selected (sometimes "norm AC"), the compressor should cycle.

"Max AC" it should stay on continuous.

Either way, a solenoid rated for continuous operation should work.

One only rated for momentary operation will fail in short order.

 

[gtx6970]

Me personally , Would wire the compressor circuit to activate a relay that controls both the compressor and the idle up solenoid . Makes for a lot less draw on the AC switched circuit.

And you can wire a thermal switch in the compressor control circuit as well. Wrap the probe around the line exiting the evaporator ( larger line btw ) and it will control compressor cycling via temps. Works like a charm

 

[Gold Rush]

He needs to clarify if it cycles or not. If stock he should be fine. If it has an updated or aftermarket system it could cycle. Knowing the correct answer would help in deciding how to power the system.

MY BAD.... Never seen any automotive a/c system that did not shut off power to the clutch when in the off mode. Can you please educate us?

 

[mpro69rr]

My self I do not think you need it. Does your compressor clutch cycle or does it run all the time? Reason is the solenoid may not be strong enough to open the throttle. Some will hold the throttle open only if the pedal is stepped on and the tension is released then the solenoid can pop out. Thats why I asked if the compressor runs all the time or cycles.

Thats what I was thinking, I would have to press the gas a little for it to pop out, hopefully it holds. The clutch will cycle when I turn the air on.

 

[mpro69rr]

Yes that is about the most convenient location to pick up the power you are wanting. If you are concerned about overloading that circuit, you could use that compressor power line to trigger a relay that would then feed 12V to the solenoid.

I don't know if the fuse protecting the compressor line will carry the extra load. One way to find out. If it pops the fuse then go the relay route.

Thanks, I'll try it and if it blows a fuse, I'll add a relay, thats a good idea!

 

[mpro69rr]

If you bought one that's specifically marketed as a "fast idle" solenoid, it should be fine.

I had trouble finding one that wasn't actually designed as a "throttle stop" solenoid meant for momentary use instead of continuous use.

I did find one that was marketed as a throttle stop, but was the same design as a fast idle.

Edelbrock and Holley both sell one but it is well over $100.

The one I found is the same part, but only $45.

I will have to check, but I think it is fast idle, I got it from holly, too expensive but I didn't feel like messing around changing a bracket.

 

[mpro69rr]

When "AC" is selected (sometimes "norm AC"), the compressor should cycle.

"Max AC" it should stay on continuous.

Either way, a solenoid rated for continuous operation should work.

One only rated for momentary operation will fail in short order.

Yes, A/C comes on when I flip the switch on the fan, thats when the idle goes down.

 

[YY1]

Is this factory AC?

 

[mpro69rr]

Thanks guys! The directions for the solenoid says to use a 12g wire, I have to check to see what the wire that controls the compressor is. I may have to use a relay. I'm thinking it may blow a fuse, not sure.

 

[mpro69rr]

Is this factory AC?

No Classic Auto Air, aftermarket

 

[pnora]

No Classic Auto Air, aftermarket

So it cycles. Power is intermittent at the clutch. You will want to wire it before the cycling switch. Classic air has two versions and each is wired different. Does your system have cables off the controls or wires with servo motors. Each will have its own way to wire.

 

[mpro69rr]

So it cycles. Power is intermittent at the clutch. You will want to wire it before the cycling switch. Classic air has two versions and each is wired different. Does your system have cables off the controls or wires with servo motors. Each will have its own way to wire.

It has wires and servo's. What do you mean before the cycling switch? Is that on the compressor itself, it only has one wire going to it.

 

[pnora]

It has wires and servo's. What do you mean before the cycling switch? Is that on the compressor itself, it only has one wire going to it.

No its not on the compressor. Look at your wiring diagram. There also is two versions of the servo control models. So the way you would wire it could be different between the two.-

 

[mpro69rr]

No its not on the compressor. Look at your wiring diagram. There also is two versions of the servo control models. So the way you would wire it could be different between the two.-

There were only two wiring diagrams, none had a cycling switch, see below. Not sure which one I have but I bought it about three years ago.