Hi guys, I'm new here and I need some help with a fan circuit.
I have recently installed a new JVC deck/head unit in my car, and it was constantly overheating so I decided to MacGyver a heatsink from an old motherboard onto the back of it. The heatsink works great and gets very hot so its doing it's job but I need to get airflow through there.
I picked up a run of the mill 80mm 12v computer case fan and wired it behind my deck to get cool air circulating. I hooked up the fan's positive wire to my car's red "Accessory" wire that only provides 12v when the ignition is turned on. I also hooked up the fan's negative wire to my car's ground.
When I turn my ignition on, all is fine and the fan spins up normally. However, when I go to shut my ignition off it makes an unnerving clicking sound behind the steering wheel and the check engine light went on. I have deducted this is because when the ignition is shut off, the fan will continue to spin until it runs out of kinetic energy, acting as a generator and pushing current back through the car's 12v Accessory wire. When I manually stop the fan with my finger before shutting the ignition off, no clicking sound and everything is good.
I have a basic understanding in electronics, from resistors, diodes, and transistors and I am more than comfortable soldering. I just need to find a way to stop the fan from acting as a generator when the power going to it is shut off.
Any help is greatly appreciated. If you need any more information please let me know.
Thanks very much!
I have recently installed a new JVC deck/head unit in my car, and it was constantly overheating so I decided to MacGyver a heatsink from an old motherboard onto the back of it. The heatsink works great and gets very hot so its doing it's job but I need to get airflow through there.
I picked up a run of the mill 80mm 12v computer case fan and wired it behind my deck to get cool air circulating. I hooked up the fan's positive wire to my car's red "Accessory" wire that only provides 12v when the ignition is turned on. I also hooked up the fan's negative wire to my car's ground.
When I turn my ignition on, all is fine and the fan spins up normally. However, when I go to shut my ignition off it makes an unnerving clicking sound behind the steering wheel and the check engine light went on. I have deducted this is because when the ignition is shut off, the fan will continue to spin until it runs out of kinetic energy, acting as a generator and pushing current back through the car's 12v Accessory wire. When I manually stop the fan with my finger before shutting the ignition off, no clicking sound and everything is good.
I have a basic understanding in electronics, from resistors, diodes, and transistors and I am more than comfortable soldering. I just need to find a way to stop the fan from acting as a generator when the power going to it is shut off.
Any help is greatly appreciated. If you need any more information please let me know.
Thanks very much!