Fan not turning on

[earnies2]

Isx my engine runs at 185 goes to the 200 uphill then fan turns on it is not working n8w what turns the fan on at 200. Is there a temp switch or fan switch thanks

[serv]

Is your truck a prostar? If so, I could not find a fan override switch in my 2011 prostar.

[rapidisimo]

Check your fan solenoid, chk for air leaks at the solenoid and the fan clutch. If you have insite run the fan diagnostic, chk temp sensors.

[Chamberpains]

Your fan should come on at 210. 200 is a little early. Was your ECM programmed for that temp? What temp does it come on at now? Or is it over heating way passed 220 and check engine/shutdown lights coming on?
What kind of truck and year?

[earnies2]

(06-10-2018 )rapidisimo Wrote:  Check your fan solenoid, chk for air leaks at the solenoid and the fan clutch. If you have insite run the fan diagnostic, chk temp sensors.

I checked the solenoid no leaks fan works fine with ac. Key on at temp fan spins free key off fan locked as it should

[earnies2]

(06-10-2018 )Chamberpains Wrote:  Your fan should come on at 210. 200 is a little early. Was your ECM programmed for that temp? What temp does it come on at now? Or is it over heating way passed 220 and check engine/shutdown lights coming on?
What kind of truck and year?

My fan always came on at 200 I am picking up a computer with insite and DLB when I get home the cel has not come on what turns the fan on? Can I add a manual switch the truck doesn't have one....its a 2009 prostar with a ISX THE SOLENOID HAS 2 WIRES ON IT THANKS IN ADVANCE

[Chamberpains]

So your highest temp is? If its not going above 220 and your not getting check engine lights than its not overheating. Or is it going that high or further?

The reason I ask is because your gauge may be messing with you. It may have always been showing the fan coming on at 200 when in reality its coming on at 210. Maybe now the gauge screwed up again and is showing a different temp. You'll know this once you hook insite up.

There are many things that kick the fan on. Coolant temp, oil temp, intake air temp, a/c pressures.

You can always add an aux manual switch to the fan. The prostar guys may be able to chime in on how to wire it. Some trucks if hooked in wrong will operate the fan but will also throw a check engine light for the fan circuit.

[Nilao]

The prostar will throw a code of you wire the fan to a switch. It monitors the current in the ground side and when you cut the ground wire to splice in the switch the ecm loses the reference voltage and throws the check engine light everytime yo break the circuit.

The only way to do this is to wire in the switch and suppress the code in the ecm program.

[Chamberpains]

If thats the case with cutting into the wiring to your original fan solenoid and you don't want to or don't have means to suppress the code. Then you can always plumb in a "normally open" solenoid after the factory 1's air line that runs to the fan and run your own wiring and switch in the dash.