Cooling Fan light on?
10-14-15, 08:33 AM
#1
Cooling Fan light on?
The light labeled "Cooling Fan" came on in my 87 Turbo II last night, and stays on any time the key is on. I tried looking in my owner's manual but the manual shows that square to be blank. I searched and didn't find anything useful. Can anyone tell me what triggers this light, or how to properly get it to shut off?
10-14-15, 09:02 AM
#4
This might help:
The electrical fan relay triggers the fan to come on because it allows a ground signal to reach the fan motor which in turn activates it to turn on. This relay, like all relays in your car, has a coil which gets voltage from the meter fuse w/key to on (since you haven't mentioned that your gauges are not working then I'll assume that fuse is good). If the relay does have voltage w/key to on at the Black/Yellow wire then the signal which activates the relay comes from a ground on the Green/Red wire. You can place a ground on the G/R wire w/key to on and if it causes the cooling fan to turn on then you know this relay is working properly and the problem resides elsewhere such as the sub relay or temp switch.
The G/R wire comes from the 2nd relay known as the "sub relay." For the sub relay to activate it needs to receive a ground signal at its coil on the Blue/Orange wire. This occurs w/the blower/fan motor on and the A/C on. The coil receives voltage from the fan fuse. When the coil receives its two proper signals (one ground and one voltage) the relay closes and allows a ground signal to pass through it on the G/R wire as it then runs to the other fan relay as previously noted. The thing is the sub relay gets a ground signal from the water temp switch. The switch senses temp,obviously, and it passes the ground signal to the sub relay. The switch has a single Green/Black wire and the switch is located by the thermostat housing. The sub relay is denoted as AC-05. Use the wiring diagram to locate this relay. Make sure its Yellow wire, powered by the fan fuse has power w/key to on. Verify that the Blue/Orange wire has a ground w/blower fan on and A/C on (ground voltage should be less than 2.5 volts). Verify that wire from the temp switch has a ground when the A/C is on and the heat of the engine builds thus activating the switch to send a ground to the relay via the Green/Blue wire which connects to the G/B wire from the temp switch. When all this comes into play the G/R wire at this relay should have a ground and the cooling fan motor should turn on given the other relay is acting properly. You could also just bypass the temp switch by placing a ground on the Green/Blue wire at the sub relay. If that gets the cooling fan to turn on then the issue likely resides w/the temp switch.
The electrical fan relay triggers the fan to come on because it allows a ground signal to reach the fan motor which in turn activates it to turn on. This relay, like all relays in your car, has a coil which gets voltage from the meter fuse w/key to on (since you haven't mentioned that your gauges are not working then I'll assume that fuse is good). If the relay does have voltage w/key to on at the Black/Yellow wire then the signal which activates the relay comes from a ground on the Green/Red wire. You can place a ground on the G/R wire w/key to on and if it causes the cooling fan to turn on then you know this relay is working properly and the problem resides elsewhere such as the sub relay or temp switch.
The G/R wire comes from the 2nd relay known as the "sub relay." For the sub relay to activate it needs to receive a ground signal at its coil on the Blue/Orange wire. This occurs w/the blower/fan motor on and the A/C on. The coil receives voltage from the fan fuse. When the coil receives its two proper signals (one ground and one voltage) the relay closes and allows a ground signal to pass through it on the G/R wire as it then runs to the other fan relay as previously noted. The thing is the sub relay gets a ground signal from the water temp switch. The switch senses temp,obviously, and it passes the ground signal to the sub relay. The switch has a single Green/Black wire and the switch is located by the thermostat housing. The sub relay is denoted as AC-05. Use the wiring diagram to locate this relay. Make sure its Yellow wire, powered by the fan fuse has power w/key to on. Verify that the Blue/Orange wire has a ground w/blower fan on and A/C on (ground voltage should be less than 2.5 volts). Verify that wire from the temp switch has a ground when the A/C is on and the heat of the engine builds thus activating the switch to send a ground to the relay via the Green/Blue wire which connects to the G/B wire from the temp switch. When all this comes into play the G/R wire at this relay should have a ground and the cooling fan motor should turn on given the other relay is acting properly. You could also just bypass the temp switch by placing a ground on the Green/Blue wire at the sub relay. If that gets the cooling fan to turn on then the issue likely resides w/the temp switch.
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10-13-15 09:09 PM