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Fan switch problem....

Old 03-03-2015, 08:17 PM
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Fan switch problem....

My car started overheating so I decided to take it to my mechanic.turns out my fan switch is coming on at 240 which is way too late.so I bought a jet performance fan switch 60600.the problem is now the switch works but comes on at 167 and my fan won't shut off.i have tried 5 other fan switches and I cannot fix this issue.my mechanic can't figure it out and I'm all out of suggestions.i don't want to add a manual switch I rather fix the issue but I cannot find anything else. My radiator and thermostat are good and coolant sensor is also good so I don't know what else to do. Can someone please help..
Old 03-03-2015, 09:31 PM
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Re: Fan switch problem....

Just to let you know,the fan is supposed to kick on at 235
Old 03-03-2015, 09:54 PM
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Re: Fan switch problem....

Originally Posted by mantaguy
Just to let you know,the fan is supposed to kick on at 235



Yea but it won't even turn on at 240.and my mechanic refused to let the car get any hotter than that so we shut it off..but fans don't come on at any tempature wether it's at 230 or at 260.
Old 03-03-2015, 10:02 PM
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Re: Fan switch problem....

What temp thermostat is in it now?
Old 03-03-2015, 11:33 PM
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Re: Fan switch problem....

It has the stock t stat
Old 03-04-2015, 10:33 AM
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Re: Fan switch problem....

One option would be to have your prom tuned to come on before it gets that hot. But maybe there is another issue. Are you sure the thermostat is working properly? Also, if you haven't already, you might check your fan relay. Also, if you have a thermal gun, you could verify that your gauge is reading accurately. Hope that helps.
Good luck!

Last edited by irockid43; 03-04-2015 at 10:36 AM.
Old 03-04-2015, 10:45 AM
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Re: Fan switch problem....

Fan Relay, Coolant Temp Switch, T-Stat. Are the fans still wired stock? Secondary fan comes on when AC is turned on and at a higher temp than 240, just don't know that number off the top of my head

Last edited by Bob88GTA; 03-04-2015 at 10:46 AM. Reason: more info
Old 03-04-2015, 10:47 AM
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Re: Fan switch problem....

Originally Posted by Calixbwsx
It has the stock t stat
stock what?? 195???
Old 03-04-2015, 01:47 PM
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Re: Fan switch problem....

240 by what, the gauge or did you do an IR temp gun check?

My gauge reads almost 30* hot.
Old 03-04-2015, 07:58 PM
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Re: Fan switch problem....

Got 240 with the gun not the gauge
Old 03-05-2015, 10:56 AM
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Re: Fan switch problem....

You've got an 89 350ci so I assume that you've got duel fans ?? If you've got duel fans then the primary fan is controlled by a signal sent by the ECM.

The secondary fan is the one that kicks on by the AC system and the temp switch in the pass side head. It's stock ON setting is 238 degrees.


These are from a 91 shop manual,.... but they might help !













Old 03-05-2015, 01:28 PM
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Re: Fan switch problem....

I used a SW555 switch. Comes on at 210 and got it at autozone.
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