My radiator fan fails to come on the fan itself is good iv replaced the radiator fan switch replaced the thermostat brand new radiator fuse and relay are good when i jump the fan out it comes on the only thing i can think of is i bought a defective radiator fan switch but i dont know any help would be greatly appreciated.

 

Stick a paper clip in the fan switch connector on the the thermostat housing. Does the fan come on?

 

yes sir it does

 

Then your fan switch is dead. Replace it.

 

its brand new tho

 

im about to just install a toggle cause this is frustrating no one seems to know the cause of this

 

test the fan switch with a multy meter

 

i had the same thing happen, the wire that's in my plug on the shock tower melted, so i had to solder the wires back together

 

There is no test method for the fan switch.

I would try another fan switch

 

Air not purged, bleed coolant

Thermostat stuck closed.

Thermister bad or giving false readings due to trapped air.*

Thermoswitch bad. Test the thermoswitch by boiling at Procedure 5.

Water pump impeller missing caused by electrolysis. Open filler cap, water should flow with thermostat removed or when the engine is at operating temperature.

 

if that was the case would my fan still come on when i jump it out

 

im pretty sure my water pumps good when its at operating temperature i can see it flowing and when i rev it it spews out and the thermoswitch is less than a month old and my thermostat is less than a month old as well and when its at operating temp my lower radiator hose is hot so i no it opening and as for air in the lines i bled it for about an hour the air never did stop so i thought it was my headgasket but then i found out i had a crack in my radiator at the seem of the top tank so i assumed thats where all the air was coming from but iv replaced the radiator less than 2 weeks ago and when i went to bleed it again i only waited for about 15 minutes and turned it off i didnt see any air but i also wasnt constanly watching it but if it is air in the system that would cause it to not turn on at all and if it is a head gasket causeing all the air in the system is there any other way to know for sure its a head gasket other than a leak down test and the combustion gas test in the system cause my coolant isnt mixing with my oil and theres no smoke coming out of my tail pipe

 

If you are concerned it is headgasket, do a block test.

 

thats what i ment by combustion gas test but that looks like thats what im gonna have to do how accurate is it do you know

 

They are pretty good, it is tube with blue fluid, you pump it, if it turns yellow you have a problem.

By the way, the fan takes a real long time to kick on.

Also, did you use an OEM new switch or an aftermarket switch? Sometimes with the aftermarket ones the harness will not click on, mine did not click, I had to really push it on it to make a connection.

 

Don't think it's been said, but what about your coolant temp sensor?? If the temp is off it won't tell the relay that drives your fan switch to engage... since you've jumped the fan switch, you've ruled out the fan switch...

 

because no ones ever bought a crapped out fan switch before. have you tried another one besides just its new? where from?

 

no i didnt buy an oem one i got a duralast one from autozone thats why i think it might be defective cause there know for it btw its the only thing iv ever bought from them i usually got to oreillys or advanced

 

no i havent i bought it from autozone thats why i think it might be defective

 

no i havent checked it and i only jumped the fan switch to see if my fuse and relay were good which they are but im pretty sure i have a blown headgasket cause theres so much air in my cooling system iv tried to bleed it twice the first time was for about an hour and the air just got worse almost to a foam and iv read that all that air will give your fan switch an inaccurate reading which is what i believe is happening but i havent done a block test yet

 

and thank you

 

i no longer have this car as when i went to put the headgasket come to find out the block is cracked thisdamnhonda