A/C Wiring Question???
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Mountain Pass
Joined: Jan 2004
Posts: 213
Likes: 3
From: Phx/Az
A/C Wiring Question???
Howdy everybody, I've got a wiring question about my A/C on my '06 Ranger. First off I don't like the fact that the A/C is setup to run most of the time.
Looking at the service tech manual wiring diagram for the A/C circuit there a 2 possible places I can put a switch to maunaly control my A/C, I can switch either; the A/C Clutch field Coil, or the A/C Compressor Cycling Switch.
What are your suggestions??
I want to run a manual switch for 2 reasons, first GAS!!! I don't need to be running the A/C now that the temp is below the 90's, (and I rarely ran at the 100's) Second I would like to take advantage of the various vent settings for warming up my feet/passengers, again w/out running the A/C. (Yes it does get 'COLD' by AZ standards in the morning).
I appreciate any and all suggestions, hints, or coments.
Thanx.
Pics of my '06 will be posted as soon as I take some.
Looking at the service tech manual wiring diagram for the A/C circuit there a 2 possible places I can put a switch to maunaly control my A/C, I can switch either; the A/C Clutch field Coil, or the A/C Compressor Cycling Switch.
What are your suggestions??
I want to run a manual switch for 2 reasons, first GAS!!! I don't need to be running the A/C now that the temp is below the 90's, (and I rarely ran at the 100's) Second I would like to take advantage of the various vent settings for warming up my feet/passengers, again w/out running the A/C. (Yes it does get 'COLD' by AZ standards in the morning).
I appreciate any and all suggestions, hints, or coments.
Thanx.
Pics of my '06 will be posted as soon as I take some.
Post Fiend
Joined: Feb 2003
Posts: 6,940
Likes: 2
From: Eastern WA
Well, I've also given some thought about doing what you have brought up and I've spent some time looking through those wiring diagrams in the factory service manual. I haven't gotten into it yet, but I was thinking about a way to convert the fan speed switch to function the same yet incorporate a push button on/off feature to operate the compressor like old (pre 95) Rangers used. I don't think it matters where you tap into the wiring at but before I went to the bother of adding the switch (in your case possibly drilling in the dash?) I would rig a temp setup to prove that there are no side effects. That A/C compressor wiring *could* have ties to the ECM that, if disturbed, might have unintended consequences. As we both know, the comp runs in all setting other than off, floor, and panel yet if you run it for just a few minutes on a high humidity day yu will be saddled with foggy windows after you shut it off, forcing you to enjoy foggy windows for awhile or keep it on. Ya know, there really ARE cool days where running the heater through the floor and defrost is nice.
Logistics Pro
Joined: Jan 2002
Posts: 4,907
Likes: 39
From: suburban atlanta
The Cycling Switch is in series on the way to the clutch field coil... I'd pick up the wire that comes out of the dashboard control head, making sure in the wiring diagram as Cowboy said that the signal to the ECM comes from there (that the A/C is engaged), so you don't get a false 'engaged' signal to the ECM. It would raise the idle speed to compensate for the load. You could also check out the other switch in the chain, the WOT switch. It disengages the clutch when the gas pedal is floored. Or at least the older ones did.
Only other thing to consider is the backfeed you'd get when you cut the juice to the coil. There should be a diode there to bleed the juice to ground when the clutch coil field collapses and generates current flow. (just like an ignition coil!)
tom
Only other thing to consider is the backfeed you'd get when you cut the juice to the coil. There should be a diode there to bleed the juice to ground when the clutch coil field collapses and generates current flow. (just like an ignition coil!)
tom
Thread Starter
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Mountain Pass
Joined: Jan 2004
Posts: 213
Likes: 3
From: Phx/Az
Thanx for the heads up on the PCM. The A/C Comp switch is in line with the PCM. My plan is to splice the switch on the ground side of the clutch field coil, or would it better to splice on the 'feed' side of the coil?
Thanx agin for your suggestions.
Thanx agin for your suggestions.
Elder User
Joined: Sep 2006
Posts: 871
Likes: 0
If you must install a switch, put it on the ground side. The computer is designed to accept an interrupt on the ground circuit, not the power circuit.
However, the A/C will NOT kick on if your switch is off, or if the switch is on either VENT or FLOOR. any other setting will kick on the A/C. They did this for two reasons - to give the compressor some action during the colder months, and because routing the air through the evaporator first pulls the moisture from the air, which aids in defrosting performance.
Also keep in mind, when the weather is cooler, your A/C pressure will be much lower, which means the compressor will not engage nearly as much as it would if actually using the A/C... believe me the difference in fuel economy will not change enough to be noticeable. You're more likely to spend more money in wire, switch, and all that than you would save by not chopping into your factory wiring.
Good luck.
However, the A/C will NOT kick on if your switch is off, or if the switch is on either VENT or FLOOR. any other setting will kick on the A/C. They did this for two reasons - to give the compressor some action during the colder months, and because routing the air through the evaporator first pulls the moisture from the air, which aids in defrosting performance.
Also keep in mind, when the weather is cooler, your A/C pressure will be much lower, which means the compressor will not engage nearly as much as it would if actually using the A/C... believe me the difference in fuel economy will not change enough to be noticeable. You're more likely to spend more money in wire, switch, and all that than you would save by not chopping into your factory wiring.
Good luck.
Logistics Pro
Joined: Jan 2002
Posts: 4,907
Likes: 39
From: suburban atlanta
Mazda...
I gotta disagree on the mpg thing, but only because of what I read about a month ago re economy and A/C use. The report stated that using the A/C did affect mileage, even more than the aerodynamic effects of having the windows open. In other words, the old saw about A/C being less expensive because the windows were closed and drag was reduced is just not enough to overcome the energy use of running the compressor.
I'd do the wiring myself, and as I can feel the compressor cycling going down the road in my old car, I'm tempted to do it on that. I hate to run the compressor just to get some airflow over the inside of the windshield. When I didn't have air, or controlled it manually, I ran the car with air coming in the defrost all the time to help keep the windshield clear.
tom
I gotta disagree on the mpg thing, but only because of what I read about a month ago re economy and A/C use. The report stated that using the A/C did affect mileage, even more than the aerodynamic effects of having the windows open. In other words, the old saw about A/C being less expensive because the windows were closed and drag was reduced is just not enough to overcome the energy use of running the compressor.
I'd do the wiring myself, and as I can feel the compressor cycling going down the road in my old car, I'm tempted to do it on that. I hate to run the compressor just to get some airflow over the inside of the windshield. When I didn't have air, or controlled it manually, I ran the car with air coming in the defrost all the time to help keep the windshield clear.
tom
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