I've been lazy and had my Lombard running for about 2 years with dead fans! I know, I'm just asking for trouble...but so far, it's never overheated. Anyway, I want to get it fixed and my question is this: How do I know if the fans themselves need replacing, or if they're just not being turned on because of faulty temperature detection?
A clue: they died about a year apart from each other.
The fans in the Lombard don't usually come on unless there are extreme heat conditions. However they do sometimes need replacing. Normally there isn't faulty temperature detection. You can check the unit for yourself. If if feels extremely hot on the bottom, then your fan should normally come on. If it doesn't you might want to try replacing the fan.
you can test you fan by removing the Ac plug and the battery. then unplug the pRAM battery on the lower right of the logic board by lifting up the keyboard and pulling the white plug with the red, black and red wires. Wait like 10 secs and then plug the PRAM battery back in. watch the fan on the left of the computer under the keyboard as you replace the main battery. The PMU should re-set and power on the screen and 'blip' the fan. if it moves, the fan works.
The fan is held in by a plug and double-stick tape.
If it doesn't move, unplug it and test it with 2 AA batteries in-line. It should move slowly. If it doesn't move, the fan is bad. If it does move, but didn't in the first test, maybe the PMU or something is bad.