Hi there guys ... been searching the whole day now broken down my MBP into its individual parts 4 times now and i hope somebody can help me... i replaced the left fan with a NEW one and the new one runs at its peak from the start up hardware test says 4mot/1/000blabla left side -0 smc reset won't work AT ALL i checked all the cables and i put the old fan back again and it works just fine but when i put the the new one back again....buyaaaaaaaaa! and don't tell me the new fan is broken MBP early 2008 10.6.8
If you've disconnected a temperature sensor, the mac will run it's fans full speed because it has no idea how hot or not it is. It's a failsafe. Make sure all your temperature sensors work.
One of the wires for the fan is used to control the speed of the fan. If there's a problem with that wire or its connection, the fan will just run at max rpm all the time. Check the wires from the fan casing and then check them at the connector end for issues.
i did that too thanks gyus i really don't know what is going wrong... i sent the fan back and will get a another one i'll le you know .. thank you all so far