Cooling Fan Not Working
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From: Kansas
Cooling Fan Not Working I got a 1998 Trans Am and my cooling fan is not coming on. I have tested the fan and it works. Checked all the fuses (2) and all Relays (3) and all are fine. What should I check next???
This dosnt have the stock dual fans either. Its ProCharged and has the single High Flo 16" fan (1)
This dosnt have the stock dual fans either. Its ProCharged and has the single High Flo 16" fan (1)
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From: Kansas
Thread Starter
Teching In
Joined: Aug 2010
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From: Kansas
Does anyone atleast know where the sensor that tells the fan to come on is located on a '98 Trans Am??
I have heard if you unplug it, the fans should automaticaly come on,,, I just cant find it!
I have heard if you unplug it, the fans should automaticaly come on,,, I just cant find it!
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From: Kansas
What do you mean fan controller? I thought the vehicles computer read the sensors and that turns the fan on?
I just need to know where the Sensors are that turn on the cooling fans? There should be one below spark plug (1) and one on the water pump somewhere right? I cant find the one on the water pump...
I just need to know where the Sensors are that turn on the cooling fans? There should be one below spark plug (1) and one on the water pump somewhere right? I cant find the one on the water pump...
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Yes the coolant temp sensor is on 1 of the heads I believe on the drivers side at the front about an inch forward of the exhaust and almost at the same height as the exhaust manifold bolts . It's 2 wires and is about the most common reason 4 cooling fans to not work . A cooling fan controller is an aftermarket device that allows You to set the fan on temp wherever You like . They are cheap ,,,,,like 15 or 20 bucks . Since You only have 1 fan now the wiring hopefully was modified correctly to continue working correctly .
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From: Kansas
Hey thanks ChrisFrost 
! Greatly appriciated. I'm gonna pick one of them up from AutoZone.
-Coolant Temperature Sensor-1998 Pontiac Trans Am 5.7L SFI 8cyl
-Part Number: SU109-Alternate Part Number: PT3378 ($15.99)
! Greatly appriciated. I'm gonna pick one of them up from AutoZone.-Coolant Temperature Sensor-1998 Pontiac Trans Am 5.7L SFI 8cyl
-Part Number: SU109-Alternate Part Number: PT3378 ($15.99)
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From: Kansas
Okay scratch that, that sensor part # SU109 Coolant Temp. Sensor from AutoZone is too big!
Its weird, it says its for a 1998 Pontiac Trans Am 5.7 Lt V8 but the threads are way too big.
Anyone know the correct part number? I need a Coolant Temperature Sensor.
Its weird, it says its for a 1998 Pontiac Trans Am 5.7 Lt V8 but the threads are way too big.
Anyone know the correct part number? I need a Coolant Temperature Sensor.
Correct Part Number 
'98 and '99+ use the same thread size, but '98 has a 3-pin connector vs. '99+ have only 2 pins.
This is tough to diagnose because the factory dual fans have been replaced with a single fan...no way to know how the fan was wired.
Normally if you turn on the AC, the fans should come on at low speed. Again, no way to know how yours has been wired but it may be worth a try.
This is tough to diagnose because the factory dual fans have been replaced with a single fan...no way to know how the fan was wired.
Normally if you turn on the AC, the fans should come on at low speed. Again, no way to know how yours has been wired but it may be worth a try.
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From: Kansas
Maybe this could be my problem. This is straight out of the procharger manual under cooling fan installation. Cheack out step 8.
7. Attach the supplied wiring harness connector to the fan wiring harness. Cut and splice the other
end of the supplied fan wiring harness into the factory fan wiring harness as shown in Illus. F4.
The black lead on the new fan should be spliced into the white wire on the factory black/white
wire connector and the light blue wire on the factory light blueigrey connector. The blue lead on
the new fan should be spliced into the black wire in the factory black/white wire connector, as
shown in Illus. F4.
8. Using a heat gun or butane lighter heat the connector ends to shrink the tubing. Tape the center
of the Y-connector to prevent a short. Verify all wires are free of moving parts and wire tie the
new harnessin place.
Im gonna check this out. Maybe I just have a short...
7. Attach the supplied wiring harness connector to the fan wiring harness. Cut and splice the other
end of the supplied fan wiring harness into the factory fan wiring harness as shown in Illus. F4.
The black lead on the new fan should be spliced into the white wire on the factory black/white
wire connector and the light blue wire on the factory light blueigrey connector. The blue lead on
the new fan should be spliced into the black wire in the factory black/white wire connector, as
shown in Illus. F4.
8. Using a heat gun or butane lighter heat the connector ends to shrink the tubing. Tape the center
of the Y-connector to prevent a short. Verify all wires are free of moving parts and wire tie the
new harnessin place.
Im gonna check this out. Maybe I just have a short...
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I also a stock 98 TA with the same problem and has take me many year to figure out what is going on, the temp of 220 is a factory setting the way it works is at driving speed the temp come down to about 212f the when in traffic or running below 30 mph it will go up to 220f + this is made to work with the catalytic converter to keep emission under control, Now if you want to fix this problem there are two things that must be done get 160 thermostat you have to have the fans reprogramed which is part of the main computer, on this car the 160 thermostat controls the lower end temp @160 and the FAN SETTING controls the high end setting @ the 212f and the 220f
You can't check relays unless you power them to trigger them and then check for continuity across the terminals of the now closed circuit.
Right now I can tell you're just trying random stuff and I get it, but if you don't know much about relays then it's likely you didn't actually test them right, you'd have to say what you did to test them for me to know though.
Have you checked to see if you are getting power to the fan and the fan connector?
Turning the a/c on should trigger the fans too unless you have issues with the a/c system also, I believe on that car the fan request is pressure dependent, where earlier systems triggered the fan when the a/c was turned on regardless of pressure.
Your car has a 10 amp and a 40 amp fuse for the fans, check both.
The wiring diagram for a 98 shows a 2 wire sensor. You can try unplugging it to see what it does. Doesn't work on all cars but it does work sometimes. That sensor should be in the driver side head at the front of the head, but on the side of it aiming toward the driver side fender.
Right now I can tell you're just trying random stuff and I get it, but if you don't know much about relays then it's likely you didn't actually test them right, you'd have to say what you did to test them for me to know though.
Have you checked to see if you are getting power to the fan and the fan connector?
Turning the a/c on should trigger the fans too unless you have issues with the a/c system also, I believe on that car the fan request is pressure dependent, where earlier systems triggered the fan when the a/c was turned on regardless of pressure.
Your car has a 10 amp and a 40 amp fuse for the fans, check both.
The wiring diagram for a 98 shows a 2 wire sensor. You can try unplugging it to see what it does. Doesn't work on all cars but it does work sometimes. That sensor should be in the driver side head at the front of the head, but on the side of it aiming toward the driver side fender.
The su109 looks right for your car, the tu280 does not. Post up some pictures of where you found the sensor and what you got from the store and that will help a lot
I checked wiring diagrams for a 98 a 99 and jumped to a 2001 and all showed a two wire coolant temp sensor
I checked wiring diagrams for a 98 a 99 and jumped to a 2001 and all showed a two wire coolant temp sensor
Last edited by 00pooterSS; Apr 8, 2019 at 08:46 PM.
