Randall G.

Wow Dave, this is completely counterintuitive to me. Must confess, I've never put a voltmeter across the fans when running. That said, the only way the final stage regulator can work is to reduce the voltage across the fan (reducing its speed). Well, it could work if it reduced the negative volts below ground (reducing the overall potential). But, this isn't the case here, considering that terminals #2 & #7 of the FSR are the "goes-out" to ground for the fans--making a negative DC voltage implausible.

Anyway, it really doesn't make sense to have a motor run faster with less voltage across it? Unless its internal resistance is variable (which isn't the case here). Though, I'm certainly open to being corrected here.

Oh, and did you mean to type BR/GR, not red/gray? The electrical schematic doesn't show a red/gray wire as the "goes-out" for either the left or right fan. The left fan is BR/RE, the right is BR/GR.

If helps any, with respect to the FSR:

Term #1 = BR/RE, from the "goes-out" of the left fan.
Term #2 = BR, to ground.
Term #3 = YE/RE, CCU, LH blower
Term #4 = GN/RE, CCU, FSR diagnosis
Term #5 = YE/GR, CCU, RH blower
Term #6 = BR/GR, from the "goes-out" of the right fan.
Term #7 = BR, to ground.
Term #8 = GN/GR, CCU, not used.

Must be a logical explanation here....

Randall G.

Oh, by the way, where in Adrian's book does it refer to the 2-13V? I can't find it. Thanks...

DaveK

Hmm- I might of meant br/gr actually......

The part in Adrians book as a note on page 335 (about 2/3rds down).

I'm glad I'm not the only one who can't make sense of the measurements I got. Definitely the right wires - they feed into the back of the fans, but don't see how they controlled the speed! At least they both work now. But - I used to have a fan squeak on low speeds, and now the RHS fan is working again - it's back. You'd think I would have put some oil in the fan while I had it open wouldn't you....

maverick

I just replaced my right side fan (passenger side USA) It had been squeeking for a while then the bearing locked up and popped the fuse. Remedy...replace the fan, parts and labour $511. THe new fan blows strongly at pos #4 moderate in pos#3 lightly at pos#1&2.It has been running 98-103deg F and the AC works great!

DaveK

This makes me think I shouldn't ignore the squeaking, and need to take it apart again to stick some oil in there. Damn!

BlackCab

when you say "squeaking" did it sound like there was a cricket in your car? My car was making a sort of noise that could be described as squeaking or chirping if the A/C was on for a while.
Maverick, are you saying you determined that to be one of the interior fans? How did you know it was the right side? Just by listening?

maverick

Yes it sounded like a cricket on and off. It would go away as you increased the fan speed. If you open the bonnet with the fan on it is easy to determine which side. Then recently the squeek went away and then it started to blow less effectivly on and off. (I guess that was the bearing on its way out!) Then it made a vibrating sound and quit all together. I replaced the 25 amp fuse and it would run and then you could hear it start to vibrate and then lock up and fuse blown again.
Cobalt on the 964 Turbo forum sent me instructions on taking it apart to oil but i never got to it. ithink it would have only prolonged the inevitable.Hope that helps.

DaveK

Mine is also a bit cricket like - and disappears with higher fan speeds (or the blower noise means I don't hear it). I'm hoping that all it means is I need a bit of lube in the fan - it's pretty easy to get to so I plan to do it this evening.

maverick

Dave,
if yours is easy to get to then you either have stuff missing or I 'HAVE A LOT OF JUNK IN THE TRUNK'!!

DaveK

My RHS is very easy - I think the left is harder because the expansion tank is in the way. But for the RHS - it's just pull up the carpet, loosen the fuse board and hang it on the wing, undo the bolts to the firewall (and cable stay), lift the firewall out, take off the clips on the fan housing and - voila - access to the fan. Takes about 30mins to get there, and about 30mins to get it back together.

Wonkdonk

Dave, slightly o/t, but where did you get your a/c recharged and does it make a significant difference to cabin temp? Obviously, fan power notwithstanding.
Cheers,
Adrian.
PS Did search but couldn't find other comments regarding your refilling other than the weight bit!

DaveK

It was recharged by a place called AirCare (they are actually mobile and the guy came to me). It did make a difference - but that's because my air con wasn't working at all - I had a leaking pipe and that meant the system had been completely empty since Autumn last year.

It's actually not in spec according to the manual - at about 25C ambient it's blowing around 12-13C, and it should be 5C lower. But in the UK, it's enough and it makes it comfortable.

Wonkdonk

Great - thanks Dave, I'll give them a call.

matthai

If the left and right blowers are swapped they become very inefficient.