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Discussion Starter #1
i have a 160 t-stat and i have always been fine driving up and down the mountains here in hawaii now for some reason i cant get the cooling fan to shut off and warm up is being a bear. temp never goes over 160 but i need it hotter than that for normal running any input?
 

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Discussion Starter #2
i checked all the weiring and every thing seems to be in order im thinking the relay crapped out ill run to the parts store and get a replacement
 

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Discussion Starter #4
yea i put a new relay in and same thing i looked at the chitons/haynes and they dont really help
 

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El☠Diablo;1620102 said:
yes its going to be the relay
Not always
Check the pressure switch for the A/c.Turning A/c on ,automatically turns on the fan so if the switch is faulty or disconnected the computer will think the A/c is on and run the fans
 

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I had the same problem with my 87 along with other issues. I changed the relay, no change.
The ECM controls the fan on 87, so I changed the ECM hoping the other problems would also be cured at the same time. Bingo all problems went away!
THe car had sat outside for 2 years in the Oregon rain so it had running issues, like it would go into the "limp home mode" so by changing the ECM evrything came back to normal.
NAPA sells rebuilt ECM's for $89.00.
Good Luck!!
 

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like everyone else said its the relays, i had the same problem when i first bought my 94
 

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yea i put a new relay in and same thing
So relay not at fault.
Only way the relay can operate is if the control wire is to ground somewhere ; either through the ECM as it is supposed to be or by a short to ground in the control wire from relay to ECM.
As noted above ; ECM will turn on fans when in limp home mode or if the A/c pressure switch is open (A/c On )
 

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Discussion Starter #10
a/c switches and the ground faults ill check these tomorrow thanks for the help. lately i had to change out the maf relay because it went bad did that and reset the ecm and car runs great but the fan stays on any how im... im trying to get all this ricky-tick before i drop in new lifters and a stage 2 chip custom burnt. but if all else fails ill just install a stand alone thermo switch and call it a day
 

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unplug the fan switch on pass. side head between 6 &8 if fan stops change switch.

unplugging the switch normally STARTS the fan running, as the switch works by increasing ohm resistance as the heat increases, unplugging it sends a HIGH ohm and starts the fans
 

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unplug the fan switch on pass. side head between 6 &8 if fan stops change switch.

unplugging the switch normally STARTS the fan running, as the switch works by increasing ohm resistance as the heat increases, unplugging it sends a HIGH ohm and starts the fans
you might want to check if its currently un-plugged as that would explain the fan running
 

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unplug the fan switch on pass. side head between 6 &8 if fan stops change switch.
On '87 + models, the sensor between # 6 and 8 plugs is for temp gauge.
Fan switch is in other head between #1 and 3 (Only fitted if car has Aux fan option ) and has no connection to main fan if still factory wiring.Only ECM controls main fan operation

unplugging the switch normally STARTS the fan running, as the switch works by increasing ohm resistance as the heat increases, unplugging it sends a HIGH ohm and starts the fans
The stock Aux fan switch closes to ground at the preset (238 F ? ) temp.
 

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Sorry to pull up an old thread but this was one of a few that came up for a C4 and helped with finding my problem. Hope this helps for a reference for others.



A/C condenser fan switch is the proper name. I found one of the metal spade connectors pushed down not making contact.



When searching and replacing the relay did not work, this led me to believe the switch was bad but found this.



All I need is a new pig tail from rock auto. Switch is available as well.
 

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I know this is old, but if opp wants over 160 why does he have a 160 thermostat installed?! 🤔
Most do it to rectify the 'running to hot' issue they think they have when the car runs 220 or so by design. That's a whole other subject. The fan running continuously will keep it from getting up to a good operating temp in conjunction with the 160. Sounds like he has a good clean radiator and cooling system to have this problem.
 

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Most do it to rectify the 'running to hot' issue they think they have when the car runs 220 or so by design. That's a whole other subject. The fan running continuously will keep it from getting up to a good operating temp in conjunction with the 160. Sounds like he has a good clean radiator and cooling system to have this problem.
he says he wants it over 160? Why then does he have a 160 therm installed was my point. Fan on all the time or not.
 

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Good question. My point would be that by limiting the fan run time it doesn't matter what t-stat you have. It will overheat at some point without the fan. And over cool with the fan running continuously with the 160. I run a 160 with the fan programmed to come on at 190 or so I believe. Works like a charm.
I have a temp switch from an 87 Buick Grand national for the Auxillary fan. It comes on around 210*. So far it hasn't came on for car stays around 200*. I will see this summer but I have ran this before on other c4's. 205* on a hot summer day is about as hot as it gets. Maybe 210 idling for a long time but I rarely drive in heavy traffic or winter with c4's...
 

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In cold weather it may never get over the 160 was my point. Thermostat is for min engine operating temperature. When you start getting peak performance etc Fans to keep it from overheating when air flow not enough to do so.
 
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