AC fuse in F50 keeps blowing. Any ideas?

There's a 10A fuse for the AC. It's blown before and I've changed it, but it keeps blowing. I've mailed my dealer but wondered if there was history of this happening with F50's?

Thanks.

 

Owed my car Ten (10) years. Not an issue.

 

Heavy current draw, often associated with a sticking fan in most everyday cars, usually from lack of use, does it happen on a low speed setting? and ok on a high speed

 

Absolutely. There was a problem at low speed and clear at high speed. Went to garage and seemed fixed on all settings but then started to blow fuses. Thanks.

 

So you can manually test this by restraining the fan and get the fuse to blow?? Interesting.

SV


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Haven't restrained anything. The fan didn't run at low speed then would kick in full blast. Now, doesn't run at all as it blows each new fuse. A short is obviously happening somewhere. It'll go back to the garage but wondered if someone here may have had similar experience so save time. Worse case I'll take off the hard top

 

If there is a connector inline with the fan then removing the fan can check the fuse again. If the fuse is fine, the it is either the wiring that may have worn the insulation or the windings in the fan have failed with a short somehow (or a capacitor or drive transistor bought it). I tend to favor a simple short in the wiring especially on a 20 yr old car!

SV

 

Thanks Keith. Will feed into the garage. They're saying it could be the compressor. In fairness they don't have the car yet and I do trust them but always worth adding some input (aka leverage) from the community! Appreciated.

 

Ok. Same principle tho. If you can find a connection, remove it and see if the symptom changes. Can quickly locate the fault area.... Good luck!

SV

 

Does the fuse blow only with AC on or does this happen with the fan on but AC off?
If this only happens with the AC on, then it is most likely the clutch in the AC compressor.
If the fuse blows with AC off, then the fan or fan resistor is most likely the issue. You said the fan wouldn't blow at low speed but only full blast before the fuse blew. That would lead me to a faulty fan speed resistor.

 

When the fan starts to stick it draws more power at low speed than at high speed hence why they are normally fine flat out, but pop a fuse on settings 1 and 2 (normal cars not F50s) then eventually it sticks all the time and the fuse will keep popping constantly.

If it was the compressor then the fans should still work just no ice cold air would appear.

This is all generic info though, not Ferrari specific.

 

He is saying the AC fuse is blowing, not the Fan fuse. If they share the same circuit (I am not familiar with F50 wiring, but a wiring diagram would help) then it could be either.
In my experience, AC fuse is for the compressor clutch and FAN fuse is for the fan. Once again, I have no idea how the F50 is configured.

 

Thanks. There's only two rotary switches, one for fan speed, the other for temp. There's no separate on/ off for AC.

 

Same fan for heat, no?

SV

 

Yep.

 

That should narrow it down a bit then, whack it over to full heat so the a/c has no reason to kick in and see if it still happens, if so then at least you can discount the a/c side of things

 

Will do. Thx.

 

Update. Garage says fan is starting to seize causing the ECU to overheat and this blows the fuse. Replacing the fan is a problem, I'm told they're not made anymore and there's none available new, so my fan will be overhauled and refurbished. Then garage will test, might need a new ECU too.

 

Good to hear they found the fault though, fan is easy enough to sort, ecu not so I imagine unless its a common part from another model

 

Ok. This doesn't make much sense to me.... But I confess I don't no what the circuit looks like. How an eco can blow a 10A fuse while driving an interior fan sounds confused.

Is it a one or two wire cable to the fan? If you can separate the fan from the ecu you can swap another fan in (assuming you can get a rating off the fan housing, e.g. [email protected]) just to see if the drive circuit on the ecu module is defective. If the fuse still blows then you know the ecu module has a defect.

Likewise, if you can separate the fan, you can test it with applying separate power to the fan...

SV

 

Thanks. I really appreciate your inputs. Honestly, I have to let the guys try and sort as they recommend. Given there's no replacement part I've little choice. But I have now have questions to ask if the quotes for more work begin to take on a life of their own. Have a good weekend.

 

Update. The car is still with the dealer. Fan has been fixed but after a 90 minute test the fuse blew again. The garage is telling me I now need a new ECU but that Ferrari doesn't supply this particular one anymore? The garage will try and find a relevant ECU replacement. Fingers crossed.

 

Can't they run a new ECU in the mean time? Like a Motec for instance. When they find another original ECU you can get that as well so to satisfy the new owner (if it ever gets one ).

 

I'll check it out thanks. Oh, and about a new owner, it's taken me a good many years and many late nights to acquire this beauty so aint going anywhere. It was first registered in Holland so can I blame you for its dodgy ecu?

 

Here is the offending ECU. Of course, no one makes them today, no spares and Digitek is out of business. Garage in fairness is working hard to establish a fix and is liaising with Ferrari, but sorting is surprisingly difficult.
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