Compressor cycling fix
06-10-2018, 10:03 AM
#1141
Member
.
STILL lovin' this Mod, so thanks to all Contributors. My Truck is a 2014 F-150 Gasser; the 'simple' 4WD Model STX.
It's hitting mid-90s F temps here in glaring Sun and intense UV @ ~6,000'. CO Humidity is 10% or 15%. I instinctively hit the sweet spot on the ~500K Pot - about halfway down - when leaving the Store, or the Dog Park. I'll leave A/C on Air Recirc for a while, and then turn off that function ~10 Minutes down the Road. The calibrated A/C Air Temp Gauge is the back of my Hand. Early on in this experimental Mod, I could hear/see some lil Frost chunks forming and blowing out the Vents when I'd dialed down the Pot setting 'too' low. Too low a setting limits heat transfer to Air blowing by, so the Air temp out the Vents actually increases as Frost or Ice forms an insulating layer. Also, a moving vs. a stationary Truck matters. Plenty of Variables. Like, Fan Speed. I'm not gonna go back to read my old Posts here, but I recall measuring 34 F and 36 F-kinda Air temps blowing out the Vents w/o Air Recirc on when the Pot was adjusted to the sweet spot of -/+ 250K Ohms. I leave the Pot at the 'Freezing A' setting to cool the Pooch, but am forced finally to increase A/C Air Vent temp. This Mod works that well. I absolutely prefer the variability of a Pot. I insulated and Foil-wrapped the 'cold' A/C Refrigerant Line long ago as part of this Mod.
I did a simple Homeboy Wire Wrap Pot connection, and will get around to a proper solder & Heat Shrink Tubing tweak some day now that the Truck Warranty has expired. I see no effect on Winter Heating function.
.
STILL lovin' this Mod, so thanks to all Contributors. My Truck is a 2014 F-150 Gasser; the 'simple' 4WD Model STX.
It's hitting mid-90s F temps here in glaring Sun and intense UV @ ~6,000'. CO Humidity is 10% or 15%. I instinctively hit the sweet spot on the ~500K Pot - about halfway down - when leaving the Store, or the Dog Park. I'll leave A/C on Air Recirc for a while, and then turn off that function ~10 Minutes down the Road. The calibrated A/C Air Temp Gauge is the back of my Hand. Early on in this experimental Mod, I could hear/see some lil Frost chunks forming and blowing out the Vents when I'd dialed down the Pot setting 'too' low. Too low a setting limits heat transfer to Air blowing by, so the Air temp out the Vents actually increases as Frost or Ice forms an insulating layer. Also, a moving vs. a stationary Truck matters. Plenty of Variables. Like, Fan Speed. I'm not gonna go back to read my old Posts here, but I recall measuring 34 F and 36 F-kinda Air temps blowing out the Vents w/o Air Recirc on when the Pot was adjusted to the sweet spot of -/+ 250K Ohms. I leave the Pot at the 'Freezing A' setting to cool the Pooch, but am forced finally to increase A/C Air Vent temp. This Mod works that well. I absolutely prefer the variability of a Pot. I insulated and Foil-wrapped the 'cold' A/C Refrigerant Line long ago as part of this Mod.
I did a simple Homeboy Wire Wrap Pot connection, and will get around to a proper solder & Heat Shrink Tubing tweak some day now that the Truck Warranty has expired. I see no effect on Winter Heating function.
.
Last edited by Engineer Guy; 06-10-2018 at 10:13 AM.
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digitaltrucker (06-10-2018)
06-10-2018, 10:11 AM
#1142
Senior Member
.
STILL lovin' this Mod, so thanks to all Contributors. My Truck is a 2014 F-150 Gasser; the 'simple' 4WD Model STX.
It's hitting mid-90s F temps here in glaring Sun and intense UV @ ~6,000'. CO Humidity is 10% or 15%. I instinctively hit the sweet spot on the ~500K Pot - about halfway down - when leaving the Store, or the Dog Park. I'll leave A/C on Air Recirc for a while, and then turn off that function ~10 Minutes down the Road. The calibrated A/C Air Temp Gauge is the back of my Hand. Early on in this experimental Mod, I could hear/see some lil Frost chunks forming and blowing out the Vents when I'd dialed down the Pot setting 'too' low. Too low a setting limits heat transfer to Air blowing by, so the Air temp out the Vents actually increases as Frost or Ice forms an insulating layer. Also, a moving vs. a stationary Truck matters. Plenty of Variables. Like, Fan Speed. I'm not gonna go back to read my old Posts here, but I recall measuring 34 F and 36 F-kinda Air temps blowing out the Vents w/o Air Recirc on when the Pot was adjusted to the sweet spot of -/+ 250K Ohms. I leave the Pot at the 'Freezing A' setting to cool the Pooch, but am forced finally to increase A/C Air Vent temp. This Mod works that well. I absolutely prefer the variability of a Pot. I insulated and Foil-wrapped the 'cold' A/C Refrigerant Line long ago as part of this Mod.
I did a simple Homeboy Wire Wrap Pot connection, and will get around to a proper solder & Heat Shrink Tubing install some day now that the Truck Warranty has expired. I see no effect on Winter Heating function.
.
STILL lovin' this Mod, so thanks to all Contributors. My Truck is a 2014 F-150 Gasser; the 'simple' 4WD Model STX.
It's hitting mid-90s F temps here in glaring Sun and intense UV @ ~6,000'. CO Humidity is 10% or 15%. I instinctively hit the sweet spot on the ~500K Pot - about halfway down - when leaving the Store, or the Dog Park. I'll leave A/C on Air Recirc for a while, and then turn off that function ~10 Minutes down the Road. The calibrated A/C Air Temp Gauge is the back of my Hand. Early on in this experimental Mod, I could hear/see some lil Frost chunks forming and blowing out the Vents when I'd dialed down the Pot setting 'too' low. Too low a setting limits heat transfer to Air blowing by, so the Air temp out the Vents actually increases as Frost or Ice forms an insulating layer. Also, a moving vs. a stationary Truck matters. Plenty of Variables. Like, Fan Speed. I'm not gonna go back to read my old Posts here, but I recall measuring 34 F and 36 F-kinda Air temps blowing out the Vents w/o Air Recirc on when the Pot was adjusted to the sweet spot of -/+ 250K Ohms. I leave the Pot at the 'Freezing A' setting to cool the Pooch, but am forced finally to increase A/C Air Vent temp. This Mod works that well. I absolutely prefer the variability of a Pot. I insulated and Foil-wrapped the 'cold' A/C Refrigerant Line long ago as part of this Mod.
I did a simple Homeboy Wire Wrap Pot connection, and will get around to a proper solder & Heat Shrink Tubing install some day now that the Truck Warranty has expired. I see no effect on Winter Heating function.
.
06-10-2018, 06:49 PM
#1143
Just pushed in a POT and gave it a short 20min test drive. Started at 500 with poor results. BUT
I believe I have a defective resistor from NAPA. I'm also wondering why temps rose from last season after replacing the Resistor, Blower and Pigtail. During a field emergency last week, 95degs temp and 55degs out the vents plus 300 miles from home, I searched out a new resistor. Now the blower cuts out on high and maybe 1or2 clicks lower. The resistor I pulled had a very slight discolor on one prong. Second one from the left and same as before. I could run at all speeds with the one I pulled.
Is it just Murphy's Law and I ended up with a bad blower motor? Is there any other cause for burning out resistors? Solder joint on the pigtail maybe?? Reaching for straws.
I purchased a Motorcraft resistor and ready to install but don't want to burn that one.
I turn lots of bolts and teach how to do the that job correctly. I'm just not the best at details of AC & Electricity to mention only 2 things I'm no good at.
Last edited by 3kushn; 06-10-2018 at 06:53 PM.
06-10-2018, 08:04 PM
#1144
Senior Member
Yes I've read enough of this to realize the simple mod. I nearly did it last year but decided to wait and see. Now I'm convinced its a safe move but needs monitoring for a while.
Just pushed in a POT and gave it a short 20min test drive. Started at 500 with poor results. BUT
I believe I have a defective resistor from NAPA. I'm also wondering why temps rose from last season after replacing the Resistor, Blower and Pigtail. During a field emergency last week, 95degs temp and 55degs out the vents plus 300 miles from home, I searched out a new resistor. Now the blower cuts out on high and maybe 1or2 clicks lower. The resistor I pulled had a very slight discolor on one prong. Second one from the left and same as before. I could run at all speeds with the one I pulled.
Is it just Murphy's Law and I ended up with a bad blower motor? Is there any other cause for burning out resistors? Solder joint on the pigtail maybe?? Reaching for straws.
I purchased a Motorcraft resistor and ready to install but don't want to burn that one.
I turn lots of bolts and teach how to do the that job correctly. I'm just not the best at details of AC & Electricity to mention only 2 things I'm no good at.
Just pushed in a POT and gave it a short 20min test drive. Started at 500 with poor results. BUT
I believe I have a defective resistor from NAPA. I'm also wondering why temps rose from last season after replacing the Resistor, Blower and Pigtail. During a field emergency last week, 95degs temp and 55degs out the vents plus 300 miles from home, I searched out a new resistor. Now the blower cuts out on high and maybe 1or2 clicks lower. The resistor I pulled had a very slight discolor on one prong. Second one from the left and same as before. I could run at all speeds with the one I pulled.
Is it just Murphy's Law and I ended up with a bad blower motor? Is there any other cause for burning out resistors? Solder joint on the pigtail maybe?? Reaching for straws.
I purchased a Motorcraft resistor and ready to install but don't want to burn that one.
I turn lots of bolts and teach how to do the that job correctly. I'm just not the best at details of AC & Electricity to mention only 2 things I'm no good at.
20 minutes isn’t a long time, but 500 is high, at least on the vehicle I have attempted this on. The pot switch, you only utilize one outside and the inner connectors, the thir is not used.
You must start tart with an otherwise healthy system. We usually set the pot, via ohm meter, then install. Some folks, after install have even disconnected the battery to reset the system.
What year truck do you have? If you blew a resistor, not sure what happened never seen that before.
06-10-2018, 09:05 PM
#1145
in the above picture where the 2 plugs are together, I assume you are asking how to get 5hat offf of 5he top of the blower box? You take a small flat screwdriver and I believe lift a small loving tang.
20 minutes isn’t a long time, but 500 is high, at least on the vehicle I have attempted this on. The pot switch, you only utilize one outside and the inner connectors, the thir is not used.
You must start tart with an otherwise healthy system. We usually set the pot, via ohm meter, then install. Some folks, after install have even disconnected the battery to reset the system.
What year truck do you have? If you blew a resistor, not sure what happened never seen that before.
I've seen settings in the 300's but early on 500 or so was safe. Maybe I am and then, everyone was being super careful. Sure that's the case.
Thanks for the reply.
06-10-2018, 09:29 PM
#1146
Senior Member
The donor truck is running at or near 360 on a pot switch. He seldom has to use recirc or max. Not sure why all/some of these trucks respond differently to the same resistor value. If you get a new pot switch, start around 375.
06-11-2018, 06:34 AM
#1147
And thanks for the resistance starting point.
My plan like so many others is find a sweet spot the POT then invest another $1 for a bag full of appropriate resistors.
06-12-2018, 01:02 PM
#1148
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Ac
I have a 2014 im wanting to add this mod. I have the part you used. I also located the sensor behind the glove box. Which color wire did you tap into and which terminals on the petentiemeter
QUOTE=Bigdog364;3681252]2011 F150 XLT crew 3.7l 168850 miles Installed 10k Ohm potentiemeter on evaporator sensor side of conector plug. Adjust to control cycling. So far... No more cycling. Temp at vents under 40 deg. $2.00[/QUOTE]
QUOTE=Bigdog364;3681252]2011 F150 XLT crew 3.7l 168850 miles Installed 10k Ohm potentiemeter on evaporator sensor side of conector plug. Adjust to control cycling. So far... No more cycling. Temp at vents under 40 deg. $2.00[/QUOTE]
06-12-2018, 01:36 PM
#1149
Senior Member
I have a 2014 im wanting to add this mod. I have the part you used. I also located the sensor behind the glove box. Which color wire did you tap into and which terminals on the petentiemeter
QUOTE=Bigdog364;3681252]2011 F150 XLT crew 3.7l 168850 miles Installed 10k Ohm potentiemeter on evaporator sensor side of conector plug. Adjust to control cycling. So far... No more cycling. Temp at vents under 40 deg. $2.00
QUOTE=Bigdog364;3681252]2011 F150 XLT crew 3.7l 168850 miles Installed 10k Ohm potentiemeter on evaporator sensor side of conector plug. Adjust to control cycling. So far... No more cycling. Temp at vents under 40 deg. $2.00
If you are just using a resistor or a pot switch: use the middle post and either left or right on the pot. On the resistor, there are only 2 sides to use. Regarding the wires that go into the temperature probe, you place the wires from the pot switch, in the plug, one on each side of the sides. same for the resistor.
06-12-2018, 02:06 PM
#1150
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Join Date: Jun 2018
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If you are just using a resistor or a pot switch: use the middle post and either left or right on the pot. On the resistor, there are only 2 sides to use. Regarding the wires that go into the temperature probe, you place the wires from the pot switch, in the plug, one on each side of the sides. same for the resistor.[/QUOTE]
So the sensor is actually left unplugged and replaced with the pot or it still stays in the loop and I attached the pot to each side?
So the sensor is actually left unplugged and replaced with the pot or it still stays in the loop and I attached the pot to each side?