I have an issue with my mac with a red light and roaring fan when it is on. It started completely out of the blue i just woke it from sleep a few days ago.

I have run the apple hardware test for powermac 2.5 and the logic board fails the extended hardware test indicated simialr to - 2FAN/4/8 failure or something

I have made sure the deflector sheild is seated / reset the PRAM etc but to no avail

I have taken a pic of the light but cant attach it - It is the one that is above the top two rams slots and about 3 inches above aligning with the power on button

It is under warranty but if there are any apple techs viewing i would like to have an idea re the issue before i take it in.

Many thanks

Hi DrewX,

there is a similar thread on G5 fan issues here:

g5 power mac fan problem

... apart from checking that each fan works yourself (and clear of dust etc), I'd take it back to have the fans assessed and/or recalibrated.

JB

Thanks for the really quick reply

I have done as much research as i can on it and that red light seems to be a diagnostic light etc

Will it actually do any good reinstaling the OS? I can seem to find that suggested anywhere else in regards to the red light issue.

Its just this thing weighs alot and its not the easiest task to take it anywhere :S

The red light has the code D58 printed on the mainboard if that gives any clues?!

I did some googling for you, and found this thread on MacNN.

Is the light flashing?

Reading the rest of that thread, it seems like it might be ram related - take out the 3rd party stuff and try again?

sounds like one of your fans has died and the others are running overtime to keep the heat down

No the red light just stays on and does not blink. Even when it is asleep it stays on.

I have tried the 'white tab' fixes mentioned on the following sites and others but to no avail

http://forums.macrumors.com/showthread.php?t=63678
http://www.mac-forums.com/forums/showthread.php?t=25977

RAM is also fine - It appears on the hardware profile and has been installed for ages. I will remove it just see if there is any change and report back

It does appear to be the drive bay fan reving also

Thanks alot for your help guys!

You have a thermal sensor problem, most likely -- either the actual sensor in one of the fan assembllies has died, or the circuitry associated with it on the motherboard has failed.

In either instance, it will need to see an authorised Apple service doctor ASAP. The longer you try and run it, the more damage you can do, especially as you still have warranty on it.

I removed the RAM - No issues nor change

I think i have tried everything reasonable i can with it so i guess its of to the repairer :s

Thanks alot for all your help its really appreciated!

if the magnetic sensor for the clear door shroud fails, then the computer will think the clear panel is off, and therefore all your fans will run at top speed.

Take it to a service centre and get them to check it out, and order you a replacement.

Also if the clear door is not in place a red light comes on the logic board if I remember correctly, get it checked out as previously stated, doesn't sound like a big issue

I sent it to the repairer today so i will post back here the issue/solution etc in case anyone has a similar issue in future.

Thanks