E fan coming on at startup (cold)?
#1
Join Date: May 2005
Location: Jackson, New Jersey
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E fan coming on at startup (cold)?
I bought my e fan during the group buy, and installed it about 2 weeks ago. On two occasions, I've noticed the e fan turn on when I start up my truck when the engine was cold. This may have happened at other times, but I've only noticed it twice. Normally, the fan works correctly and doesn't turn on until the engine reaches the set running temperature. I haven't moved the position of the temp setting, and I have all of the wires hooked up correctly with the exception of the green wire that goes to the AC -that one is capped off because I have no AC at the moment.
I'm not too worried about this, for now as long as the fan is running I am happy, but what could be the cause of this, could it be user error?
I'm not too worried about this, for now as long as the fan is running I am happy, but what could be the cause of this, could it be user error?
#3
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#6
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For the water and controller idea...
We've been having alot of dew in the mornings lately, maybe some of that got in the controller? I'm wondering if this could be the issue, because on both occasions where I noticed the e fan running at startup it was in the morning. Then when I started it up in the afternoon, it was functioning properly.
We've been having alot of dew in the mornings lately, maybe some of that got in the controller? I'm wondering if this could be the issue, because on both occasions where I noticed the e fan running at startup it was in the morning. Then when I started it up in the afternoon, it was functioning properly.
#13
My guess is similar to what my homemade controller does.
Since it's measuring temperature in some way, it's possible for the battery voltage droop seen during startup to look like a high temperature.
The reason for this is that most sensors used in automotive work are NTC thermistors -- a fancy name for a sensor whose resistance goes down as temperature goes up (negative temperature coefficient = NTC). Most controllers apply a current through a resistor to one end of the sensor, and connect the other end of the sensor to ground. The voltage across the sensor is then inversely proportional to temperature -- that is: is goes down as temperature goes up.
So, the voltage droop causes that voltage to also droop and it looks to the controller like the water is hotter than it is.
My controller often turns the fan on briefly when I start the vehicle. Yours could be doing the same thing.
Or it could be whacked, lol...
Since it's measuring temperature in some way, it's possible for the battery voltage droop seen during startup to look like a high temperature.
The reason for this is that most sensors used in automotive work are NTC thermistors -- a fancy name for a sensor whose resistance goes down as temperature goes up (negative temperature coefficient = NTC). Most controllers apply a current through a resistor to one end of the sensor, and connect the other end of the sensor to ground. The voltage across the sensor is then inversely proportional to temperature -- that is: is goes down as temperature goes up.
So, the voltage droop causes that voltage to also droop and it looks to the controller like the water is hotter than it is.
My controller often turns the fan on briefly when I start the vehicle. Yours could be doing the same thing.
Or it could be whacked, lol...
#17
Just after installing my efan (thanks again Jeff!) a couple of days ago, I had a wierd problem with the a/c today after driving around houston all day, everytime I started the truck the a/c would cut out/lag for a couple of minutes (really annoying as it was hot as hell today), just idling, then would pick back up when I started driving and would be fine.. the fan also comes on when I start the truck (with or without the a/c being on). Any ideas?
#18
#19
#22
Originally Posted by bwester04
Is it supposed to come on upon a cold startup even with the a/c off?
although for your it wont be an issue because you dont have sub zero temps when you wont want your fan blowing cold air onto your engine...
#23
#24
Originally Posted by 4X2XLT
no... did you set the dial or no? because that could be whats going on...
although for your it wont be an issue because you dont have sub zero temps when you wont want your fan blowing cold air onto your engine...
although for your it wont be an issue because you dont have sub zero temps when you wont want your fan blowing cold air onto your engine...
#25