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1989 7mgte swapped mk3
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Discussion Starter · #1 ·
I was wondering under what conditions the 2 condensor fans will kick on when the AC is running. I know the fans themselves work because I took them off and put some power to them. I want to know how to get them off to see if the relay in my car is working...thanks
 

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me me me me me me!!!
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483 Posts
i thought they are supposed to come on as soon as the clutch engages on the ac pump. but i'm not sure since i have flexalites. i'm converting it back to stock i just need a shroud now.
 

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92 TURBO
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1,008 Posts
hornet7288 said:
I was wondering under what conditions the 2 condensor fans will kick on when the AC is running. I know the fans themselves work because I took them off and put some power to them. I want to know how to get them off to see if the relay in my car is working...thanks
There are 2 conditions that turn on the fans:
1st is when the A/C is turned on and the high side pressure reaches 220psi which than closes the high pressure switch which is mounted in high side line on the pass. side. The high side HAS to reach 220psi before the fans will turn so if it's not hot enough outside or if your system is low or empty of refrigerant they won't turn on under this condition. The switch opens when the high pressure drops below 178 psi switching off the negative ( ground ) feed to the condensor fan relay coil.

2nd way is when your coolant temp. hits 212 F ( 100 C ) At 212 F the temp. switch on the thermostat elbow ( it's the lower one with the blue w/ white wire with the blue connnector plug ) closes to engine ground. When coolant temp. drops below 203 F ( 95 C ) it opens the switch to turn off the fans.
You can check the operation by removing the connector from the lower temp. sender ( blue one ) on the thermostat elbow and grounding this wire to energize the condensor fan relay which is mounted by the battery.
Mike
 

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aka supra_driven
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196 Posts
so if u wired up after market fans to the condensor fan wiring they should turn off and on like it should. Or is that not advisable?
 

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aka supra_driven
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196 Posts
not a good idea to have them run all the time cause the fan motor will not last. What i'm saying is that if u wired the fans to the condensor fan the fans would turn on when coolant temp reaches 212 F and turn off when the coolant cools to 203. this way they will not be on all the time. And they would certainly not come on during highway driving since most cars don't run that hot anyways.
 

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92 TURBO
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1,008 Posts
^There's no point in running them continuously since you don't need them on when you're ramming air thru the radiator at speeds over 30mph or when it's cold out. DC motors have brushes in them that wear out with usage. I would just connect them up like the original 2 condenser fan motors were. The stock relay and 40 amp fuse which services both should carry the load (amps) and you'll retain automatic control with the stock temp. switch and A/C pressure switch.
 

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Ask First Search Later
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519 Posts
really?i i had a 91 celica and the shop i took it to said to run them full time.ok so now when i get them on the supe i know better.sorry about the wrong information!
 

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aka supra_driven
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196 Posts
i'm not familiar with aftermarket fans like the flexlites. Do they come with their own coolant temp switch to turn the fans on and off?
 
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