Car overheats ...because fan is not working....

if I connect directly to battery ...fan does work so fan is not a problem...

it could coolant temp sensor or is there any switch that activates fan?

I know where temp sensor is ....and where is relay but not sure where is switch (if any)

please advise if any fan activating switch is there ..if so location?

 

The fans are controlled by the engine computer and do not operate all the time. They only come on under certain conditions. The computer uses input from the coolant temperature sensor and other information to decide whether the fan should come on. The same temperature information is used to show the temp on the dash. If the dash is reading hot then probably the fans should come on. If they are not, and if the fans themselves and the relays are good, then the problem could be in the computer or the wiring between the computer and the relays.

 

In order for fan to come on...is there any particular switch that energizes low and hi rad fan relay or there is no actual switch but PCM read temp. from coolant temp. sensor (which is a part of that assembly that connects to upper hose with bleeder screw) and turns the fan on?
I just want to make sure that there are no two separate switches that activates low rad fan and high rad fan

Also at what temp. low fan should come and what temp high should come on ?

 

As I said previously, the fans are controlled by the engine computer. I also previously gave you the temperatures at which the high and low fans should come on.