electric fan question

[gr8t1hex]

I already used the magic search button but did not find a definitive answer to this question so here it goes.....Do the electric fans come on only when the a/c is on or are they also supposed to come on when the engine is hot? I've read here that only when a/c is on, others say when engine is over a hundred degrees. My car runs around 90 when a/c is on and the electric fans do kick in but if I am stuck in traffic without the a/c on a hot day the temperature has risen as much as 110 without the electric fans kicking in. If someone knows the exact operating parameters of the electric fans please let me know so I can determine if I have a problem or not. Thanks in advance.

[jnenad16]

the aux fans kick on when the ac system pressure raises over 16bar, and when the coolant temp reaches 100*celsius.

nenad

[gr8t1hex]

okay so they are not turning on when it's over a 100. what should I check? relay or some sort of switch?

[jnenad16]

possible causes:
-bad aux fan relay(high speed)
-bad coolant temp sensor
-loose connection
-blown fuse(if any)

do the fans work when the ac is on?

nenad

[gr8t1hex]

yes they are working fine when the a/c is on but i've never heard them go off when the a/c is off. I'm thinking maybe a relay because I changed the temp sensor about a year ago. If I can't narrow it down i'm probably going to remove the fan clutch setup and go with an electric fan as my main fan sort of like the one you said you had. Did you notice any significant voltage drain with your aftermarket setup.

[jnenad16]

well, Im not sure if your refering to the fan switch or the fan itself, but I did install a primary electric fan in place of the fan clutch, but it wasnt sufficient. and I wasnt able to put in a bigger, higher cfm one because there wasnt enough space, so I had to revert to the fan clutch. I did however install an adjustable switch for the aux fans to turn then on at about 83*celsius, that way engine temp would never vary so much, and it would stay at constant 81-83*. this is the switch I use on all of my cars:
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=110805&prmenbr=361
works great!

nenad

[gr8t1hex]

i might try that. Do you know where is the sensor or switch that activates the electric fans based on temperature instead of a/c based activation? Thanks for info.

[jnenad16]

that would be the coolant temp sensor, its the four prong sensor on top of the water pump, next to the thermostat housing.

nenad

[gr8t1hex]

okay then then something must be wrong with the temp sender or the plug. when i unplug it the fans kick on. But regardless of how high my temp reads the fans only kick on when my a/c is on.