Cooling Fan Won't Turn On
07-26-2015, 03:15 PM
#1
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Car: 1991 Camaro RS
Engine: Built TBI 350
Transmission: T-5
Axle/Gears: 3.42 Posi
Cooling Fan Won't Turn On
On my 1991 RS, I have a swapped 350 and the cooling fan won't turn on. I replaced the connector and the switch on the motor. However, when the AC is on, the fans kick on! Anybody know what it is?
07-26-2015, 08:47 PM
#2
Re: Cooling Fan Won't Turn On
There is a fan control switch in the passenger head by the #6 cylinder just in front of the dip stick. This controls when the fan turns on.
Make sure it's hooked up. If it isn't, that's probably the problem. If you hook it up and it still doesn't turn on when the3 car gets up to temp, disconnect the wire and ground it to chassis ground with the key in the "run" position but the car not started. If the fans turn on, then you have a bad switch. If they don't, the relay is bad (but the switch may still be bad). Replace the relay and try again. If it stilldoesn't turn on when hooked up, but does when grounded then the switch is bad.
We know the power cicuit and the fans themselves are good since the fans turn on with the AC.
Make sure it's hooked up. If it isn't, that's probably the problem. If you hook it up and it still doesn't turn on when the3 car gets up to temp, disconnect the wire and ground it to chassis ground with the key in the "run" position but the car not started. If the fans turn on, then you have a bad switch. If they don't, the relay is bad (but the switch may still be bad). Replace the relay and try again. If it stilldoesn't turn on when hooked up, but does when grounded then the switch is bad.
We know the power cicuit and the fans themselves are good since the fans turn on with the AC.
07-28-2015, 09:15 PM
#3
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Car: 1991 Camaro RS
Engine: Built TBI 350
Transmission: T-5
Axle/Gears: 3.42 Posi
Re: Cooling Fan Won't Turn On
There is a fan control switch in the passenger head by the #6 cylinder just in front of the dip stick. This controls when the fan turns on.
Make sure it's hooked up. If it isn't, that's probably the problem. If you hook it up and it still doesn't turn on when the3 car gets up to temp, disconnect the wire and ground it to chassis ground with the key in the "run" position but the car not started. If the fans turn on, then you have a bad switch. If they don't, the relay is bad (but the switch may still be bad). Replace the relay and try again. If it stilldoesn't turn on when hooked up, but does when grounded then the switch is bad.
We know the power cicuit and the fans themselves are good since the fans turn on with the AC.
Make sure it's hooked up. If it isn't, that's probably the problem. If you hook it up and it still doesn't turn on when the3 car gets up to temp, disconnect the wire and ground it to chassis ground with the key in the "run" position but the car not started. If the fans turn on, then you have a bad switch. If they don't, the relay is bad (but the switch may still be bad). Replace the relay and try again. If it stilldoesn't turn on when hooked up, but does when grounded then the switch is bad.
We know the power cicuit and the fans themselves are good since the fans turn on with the AC.
07-29-2015, 11:58 AM
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Car: 87 Formula/ 00 Xtreme
Engine: TPI 305/ v6
Transmission: struggling t-5/ 4l60E
Axle/Gears: 3.08/ 3.23
Re: Cooling Fan Won't Turn On
The fan turns on, you already know the relay is fine. The problem is somewhere in the wire from the fan switch to the relay if grounding it doesn't make the fan turn on.
(TBI is single fan Ozz
)
(TBI is single fan Ozz
) 
07-29-2015, 05:49 PM
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Car: 87 Formula/ 00 Xtreme
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Transmission: struggling t-5/ 4l60E
Axle/Gears: 3.08/ 3.23
Re: Cooling Fan Won't Turn On
Interesting to note. The 88+ years did get a relay type change and some minor wiring changes. Might be part of it, never know with gm...
Everything for turning the fan on, on a '91, ties to the fan relay coil ground though. Oddly, TBI is not an ecm controlled fan.
Everything for turning the fan on, on a '91, ties to the fan relay coil ground though. Oddly, TBI is not an ecm controlled fan.
Last edited by deadbird; 07-29-2015 at 06:06 PM.
07-29-2015, 09:39 PM
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Car: 1991 Camaro RS
Engine: Built TBI 350
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Re: Cooling Fan Won't Turn On
Did I ever metion that the temp gauge works?
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07-29-2015, 10:09 PM
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Car: 87 Formula/ 00 Xtreme
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Re: Cooling Fan Won't Turn On
That has nothing to do with your fan.
08-02-2015, 12:30 PM
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Car: 89 trans am
Engine: 383
Re: Cooling Fan Won't Turn On
I have the exact same problem. I get 12 v at the relay, the wire going to my fan from the relay works, when I turn the car on I get 12 v on the other small wire. The green wire with a white strip will turn the fan on when I ground it off the relay. Looking into it today why its not being activated.
08-02-2015, 02:58 PM
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Car: 89 trans am
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Re: Cooling Fan Won't Turn On
Ok so I don't see any other fan switch like people are talking about. I have a temp switch screwed into the drivers side that works great. Then the other coolant switch is on the top of the intake by the radiator intake. This switch has 2 wires going to it with around 5 v reading. I jumped that switch and still no go (motor was cold).
When I ground the green / white wire on the relay the fan kicks on. I traced it back to the computer. Cant I just run a jumper off my gauge temp switch to my relay??? Will this mess anything up? Help Help
When I ground the green / white wire on the relay the fan kicks on. I traced it back to the computer. Cant I just run a jumper off my gauge temp switch to my relay??? Will this mess anything up? Help Help
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