Should the removeable fan assembly fans be spinning?

Question

10 Days ago my 2.5 GHz Quad Power Mac G5 froze and I had to cut the power. Upon trying to turn it back on, it wouldn't power up so I brough it to Apple for repair.
A few days ago I was told the logic board had been replaced but the problem wasn't totally fixed and they were awaiting another part as the problem was not totally solved. I picked it up today to find only the power supply had been replaced. Got it home, plugged it in, and there wasn't any video and after a little while some (all?) fans switched to running at full speed. It was very loud.
Brought it back and it was immediately looked at. Initially everything was fine but thankfully after a while the video got flakey. They replaced the video card and I brought it back home.
The good news is that at the moment it's working however I happened to notice that the fan assembly fans aren't spinning. Hardware Monitor reports activity for all the fans it's monitoring so this must be two it can't. I am speaking of the assembly that one would pull out to replace RAM and/or reset the PMU. I called the Apple store and spoke with the tech who said sometimes they don't spin at all and not to worry.
Well, I'm a little worried. If anyone has a current model G5 I'd appreciate if you could check your fans and tell me what you see. You can shine a flashlight through the front grill or pop open the side panel. I don't know if they used to spin and I don't know if they are intake or exhaust fans. The two exhaust fans at the back of the case seem to be working as does the video card fan.
Thanks.

Answer 1

By "DP2" I guess I was really saying, "I don't have a quad, which is liquid-cooled, and therefore may have different parameters for the fan behaviour than this Rev.A Dual-Processor 2GHz, (as opposed to Dual-Core 2GHz) and that said, this is the best answer I can come up with". We try to help.
Anyway... the fans in this G5 "DP2"(but maybe not the quad) are:
2 PSU fans - at the front, behind the silver grille, below the lower internal metal plate, inaccessible, not reported on by HM, presumably running at a constant speed
Next up, at the front, beside the puny internal speaker, is what HM calls the "PCI Slot Fan"(expansion slots), (currently, usually, running at 35%)
Moving to the back of the G5, at the top, with a silver wire guard, in front of the hard drives, is what HM calls the "Drive Bay" fan (currently, usually, running at 1000RPM)
Beside this Drive Bay fan, in a grey plastic housing, at 90deg, is what HM calls the "Main Logic Board Backside" (currently, usually, running at 20%) [this pulls air over the back of the main logic board, through the Memory Controller Heatsink]
Then, behind the CPU heat-sinks, at the very back, are the two fans that HM calls "CPU A (&B) Exhaust Fan" (speed very variable - "Specified Upper Limit - 3200 RPM", "Specified Lower Limit - 300 RPM")
In front of the CPU heat-sinks, the two fans that you are interested in, in a removable sliding plastic housing, which HM calls ""CPU A (&B) Intake Fan" (speed very variable - Limits as for Exhaust)
Just discovered, somewhat late in the day perhaps, that while HM (hopefully) reports actual temperatures from the various sensors around the G5, the fan speeds reported are not the actual speed of the fans, but the speed at which they are being instructed to spin by OS X. This could be verified by tilting the clear plastic deflector panel outwards, but keeping the locator pegs in place, and withdrawing the sliding "CPU Intake Fan" housing from the connector; the fans will stop - but HM will continue to report the OS X-instructed fan speeds.
From your description it sounds as though the sensor identifiers that HM is picking up from the quad are different(to the "DP2") and also it's just possible that HM is not fully optimised for either the hardware and/or OS X 10.4.6. (HM is at v.3.4 (March 2, 2006) and so should be quad-aware)
Anyway... "bottom line" - judging by this "DP2" and a quad sample of one(thanks KentZ!), your "CPU Intake Fans" probably should be turning all the time. As yours don't - it's possible your quad may have a different, but appropriate, Thermal Calibration.
If you load up the processors and observe the fans through the clear plastic deflector panel and they still never spin, (and also HM reports they should be) you must surely have either a bad connection to the fans or faulty fans. If they both never move, it would seem likely it's a bad connection.
Hope some of this helps. Post again if it doesn't.
Of course, a few more quad users' experiences (with 10.4.6)would be even better...