I've got a 2016 Superb 3 and out of the Blue the heater blower fan stopped working, the mechanic thought it was the relay pack, so I had a new heater blower complete with relay pack fitted, but it made no difference, upon further inspection there is no power to the unit and the fuse is ok.

Has anyone else had this problem, is so, what was the fault.

Has it been scanned for codes? Worth going to a VAG specialist to scan if you don’t have the kit yourself.

I think the mechanic did run a scan which showed there was no voltage to the blower, so he checked the fuse, but that was ok, maybe I need an auto electrician

The air blower is supplied by a 30A fuse in slot 14. If this is ok then its power comes from the BCM. The BCM’s job is to monitor voltages and cut power if there is any problem. But this should give a fault code if its active.

@Binx1310

Sorry, I need to correct you. The fresh air blower, labeled V2 in the wiring diagrams, has no connection to the BCM at all. It's a LIN SUB device connected to the Climatronic system. You have the power supply directly from fuse SC14 (30 amps), which is terminal 30, as well as ground from a central ground point, both 4 mm². The LIN connection is a 0.35 mm² cross-section and, as mentioned, goes to the Climatronic. Of course, you also have a potential source of error with the blower itself, VW calls it J126, the control unit for the fresh air blower.

Personally, I would simply replace the blower and control unit. Of course, the blower alone is also available.

Edited Saturday at 03:465 days by Cairus

12 hours ago, Volvster said:

so I had a new heater blower complete with relay pack fitted, but it made no difference, upon further inspection there is no power to the unit and the fuse is ok.

Confirm 100% that the correct fuse was looked at.

Fit a new fuse yourself, if it wasn't you that previously checked it.

Where is fuse SC14 (30 amps) on a UK car, if I can pull it out I can test it with a multimeter.

Whereabout on the car is the fuse panel, is it the one behind the passenger glove box

Dunno, but probably yes.

In the cabin somewhere rather than in engine bay.

Thanks @Cairus for the correction. The wiring diagram is confusing as it shows the BCM on the same page so I assumed there was some connection to it. apologies for any confusion.

Yes this fuse box is the one accessed by pulling down the glovebox door on a RHD

On 30/05/2026 at 04:44, Cairus said:

@Binx1310

Sorry, I need to correct you. The fresh air blower, labeled V2 in the wiring diagrams, has no connection to the BCM at all. It's a LIN SUB device connected to the Climatronic system. You have the power supply directly from fuse SC14 (30 amps), which is terminal 30, as well as ground from a central ground point, both 4 mm². The LIN connection is a 0.35 mm² cross-section and, as mentioned, goes to the Climatronic. Of course, you also have a potential source of error with the blower itself, VW calls it J126, the control unit for the fresh air blower.

Personally, I would simply replace the blower and control unit. Of course, the blower alone is also available.

Do you know what the control unit for the fresh air blower is called

Do you know what the control unit for the fresh air blower is called

Fan regulator - J126

https://www.skoda-parts.com/spare-part/5wa907521-fan-regulator-skoda-28981.html

I've replaced the heater/blower unit complete with new relay pack, the F14 fuse is intact and voltage is getting to the blower, so does this only leave the Fan regulator - J126.

The symptoms were that the fan was intermittent then it stopped working altogether.

Isn't the thing you are calling 'relay pack' the same thing as "fan regulator - J126'?

It doesn't contain any relays, I don't think, transistors instead.

Follow Binx1310's link to look.

If power is getting to that but not to the fan motor then either that new J126 is faulty, or it isn't getting the necessary information to know what it should do.

There is a thin communication wire that tells J126 what to do, coming from the Climatronic module, as @Cairus described a few posts back.

That wire may be damaged or have a poor connection at either end of itself.

On the J126 connector, the 4-pin connector is labeled T4ad/4 ---> Pin 4 ---> color violet/blue

The counterpart is the J65, the 20-pin connector labeled T20e/16 ---> Pin 16

1 hour ago, Breezy_Pete said:

Isn't the thing you are calling 'relay pack' the same thing as "fan regulator - J126'?

It doesn't contain any relays, I don't think, transistors instead.

Follow Binx1310's link to look.

If power is getting to that but not to the fan motor then either that new J126 is faulty, or it isn't getting the necessary information to know what it should do.

There is a thin communication wire that tells J126 what to do, coming from the Climatronic module, as @Cairus described a few posts back.

That wire may be damaged or have a poor connection at either end of itself.

Skoda actually call what I called the Relay Pack as a Fan Regulator, which comes ap part of a new Blower unit and there is power coming to both the old and the new units, so I would assume these are working ok, Fuse F14 is fine, so I will have to start looking at disconnected or loose wires, it could also be the control unit on the dashboard.