1. https://www.google.com/search?hl=en&as_q=Dell+Dimension+4550
2. All I find is "Quite simply the fan and shroud are an assembly. Unplug the power connector for the fan from the motherboard first."
So you'll have to look on the motherboard for a matching connector and then see if it's marked FAN.
Bob
The CPU fan's lead in my Dell Dimension 4550 computer has become unplugged and I cannot see where it plugs in?
I have looked everywhere inside the case but cannot see where it goes, can anyone help please?
Thanks
Colin

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