Because it can allow the engine to overheat.
Car cooling fan control circuit.
On applications that have variable fan speeds.
The vehicle s pcm s function is to act as a ground to operate components not to supply power.
What causes the p0480 code.
Engine cooling fan issues.
Now take the power wire from your fan and connect it to the wire that is going through the firewall.
The fan may work but it only runs at low speed.
A constant power supply from the battery is present on a terminal in each of the relays.
A switched terminal will be hot only when the key is on.
This one turns on the fan when the circuit is closed.
The engine may also overheat if fan speed fails to increase when additional cooling is needed.
The temperature controlled switch is designed to turn the fan on when coolant temperatures reach 195 degrees and turn off the fan when temps drop to 185 degrees.
On older fan circuits the thermostatic switch connects to battery power on one side and to the fan motor on the other.
During the install christian shot.
The electric cooling fan uses a direct current dc electric motor with a thermo switch module or computer control to turn it on or off depending on coolant temperature or ac operating condition.
This will be the wire that connects your switch to your fan power wire.
So now we have a wire that goes through the engine bay to the cabin of your car.
The ecu then triggers a check engine light to illuminate on the dashboard.
Get the 10 gauge wire and place it through the hole in your fire wall.
The vehicles ecu has tried to control the cooling fan 1 and it has failed to operate or a fault was detected.
Or a failure of the fan relay or control circuit is bad news.
The fan relays are nothing but a remote light switch.