A/C Hot at idle after MADFAN install / SCT Dyno Tune ---

[alwayscode390]

I am not sure whats causing this.

I installed the madfan and got a dyno tune with the SCT tuner on the same day.

Now my A/C is blowing GREAT all the time , BUT when I am at idle ( at a stoplight ) it blows HOT ... and then when I start moving it gets ice cold.

Do you think this is something with the fan or the tune?

The truck temps stay good so far in 108 degree weather.

What do you think is causing this?

Thanks ---

[Massive1]

I have the same problem with mine, i haven't tuned it or installed performance parts, but after spending some money on the dryer, compressor, lines and filter my a/c still stops cooling when i do long pauses ex: traffic lights.

[fordfx497]

well obviously it means there is not enough air being drawn across the a/c condenser at idle, i kinda have the same problem in the hottest part of the day...............

[alwayscode390]

Honestly it may have been happening before the mods ... I bought the truck in October and really havent used the AC much.

If I used it , it was on a high 80 degree day for a few minutes ... so maybe its just the REAL hot temps showing what it can do to the STOCK truck setup?

Thanks guys ---

[Blind]

mine works fine at idle with a stock fan in socal and in vegas, up to 108* on the outside temp thing.

my guess would be the fan doesn't kick on with the madfan controller unless the compressor is cycling or something. Whenever you're moving it doesn't need the fan to cool off the a/c condensor.

[HiTechRecneck]

First thing to note is that the stock gauge is not going to move until it gets HOT!! I would add a real temp gauge with real numbers to see where you are at. I had the same issues and never knew it because the stupid factory gauge did not really let me know it was getting hotter than I would like for it to be!
Second, the A/C system will drop temps so many degrees from the outside air so there is a point where the outside air is just so hot that it can't cool it down much because it is starting out so hot in the first place.
Also, the Madfan controller should kick it from low to high speed at about 205 degrees on either the radiator or A/C sensor so you may want to make sure the fan is speeding up as it should.
Condition of the radiator itself can also make s difference - remember these trucks are about 10 years old now. I just replaced mine with an L radiator with 1 more core from Rockauto.
Idling is the hardest thing in this heat because it is not moving enough air through the radiator to keep everything nice and cool. Also, the A/C condenser can actually gain heat from the radiator in extreme heat.

[cayman150]

I noticed the same thing the other day and now this is now happening to me as well.

AC blows cold when moving but hot at idle. I mean when I first started the truck up in the garage the AC was blowing hot air. It was coming out all of the correct vents so I don't think it is an o-ring issue.

I have the LFP e-Fan and I suspect it has something to do with the relays not tripping the fan on at low speed whether the engine is at temperature to require cooling or not.

I think I remember my e-Fan coming on when the AC was switched on regardless of whether the engine needed cooling but that isn't happening any more. I know it was loud when the e-Fan came on in the garage cause it's enclosed in a small space.

Time for me to hit up Mike over at MAD Enterprises for a new e-Fan relay wiring harness I guess.

[oki916]

The fan is not running at idle as said before...as air is not moving across. You need to go to the controller and turn the little knob to activate the fan at a lower temp. Personally with my built motor I turned the knob all the way down so the fan is on immediately when the truck is on...of course I am built and don't run the truck everyday, so life of the fan being constantly on isn't a concern for me.

[tpr103]

Are you sure the fan is working on high?

[TX Harley Guy]

Mine has done this for years, even after a new A/C system, on a really hot restart or sitting in traffic for long periods, I dont worry about anymore, stock fan, stock motor.

i have a Madfan ....in the box.

[1Bd Bagr]

wow...my AC blows ice cold even idling on a 110 degree day. I think i'm not going to mess with my trucks fan system.
Tim

[AjayBrown]

Is the fan setup to run at high when the a/c is on? If not there is no air flowing across the condenser, causing the head pressures to get to high, shutting the compressor off.

[cayman150]

I must have somethg wrong with my relay's but my system came from LFP and not MAD.

I don't see the knob for the controller to turn that Oki is referring to on my system.

All I have is a seperate switch that I can force the high speed to come on.
My fan isn't coming on at all unless I manually switch the high speed on so I guess there is a fault in my low speed relay?

Awhile ago I looked into replacing my wiring harness with MAD's version but just never pulled the trigger yet. Guess it's time now as a lot of people have had trouble with the older LFP wiring.

[Madferraristi]

A customer was having an issue with his A/C blowing warm if he got caught in traffic on a really hot day, we tried something and it worked perfectly for him.

We clipped off the Green wire where it enters the Controller (cut short and seal the end with a dab of silicone) and then reconnect it to the same terminal as the small Blue wire. This will put the fan into high speed on hot days if the A/C needs more airflow when you stop. This has become standard procedure for us as of the first of September.

It is odd that the MadFan has been in production since 2004 and here eight years and hundreds later an issue as basic as this pops up.

Mike

[oki916]

I must have somethg wrong with my relay's but my system came from LFP and not MAD.

I don't see the knob for the controller to turn that Oki is referring to on my system.

All I have is a seperate switch that I can force the high speed to come on.
My fan isn't coming on at all unless I manually switch the high speed on so I guess there is a fault in my low speed relay?

Awhile ago I looked into replacing my wiring harness with MAD's version but just never pulled the trigger yet. Guess it's time now as a lot of people have had trouble with the older LFP wiring.

its not a knob...its a little flat head screw top. Seriously it took me a lil while to find...need to get a picture of what I am talking about. It it is the temp control for the fan to come on (IIRC). You seriously have to use one of those lil tiny screwdrivers you use for computer repair.