Hedgehog

[henrym3]

Yesterday I went to the x to find that my heater blower wasn’t working. No previous faults or hiccups and working perfect when I parked the previous night. Checked fuses and diagnostics tell me it’s getting voltage and shows percentage when the button is pressed up or down. I wasn’t aware that the hedgehog can just stop working, panic has now set in that it’s the fan motor. Sent for a hedgehog as it’s the easiest fix. Any thoughts.

[sapphireblack]

From fading memory of E53 ownership, i think the hedgehog usually plays up causing issues, but can just quit too. Probably the wisest thing to replace first anyway.

[Leslie]

Probably same as the e46 one and I put about 4 in when I had mine inc genuine ones that didn't last much longer it seemed either . No fan is usually the hedgehog though

[henrym3]

Thanks guys, hopefully it will arrive tomorrow.

[X5Sport]

One note from other recent replacement is don’t use chinese copies. They’re cheap for a reason!. It’s pot luck as to whether you get a good one.

[Alan Gunn]

Mine just stopped like yours.
Easier job than on the e46 i had to change only about 10 minutes.

[henrym3]

Ok new resistor in and no change. There must be a way to put 12v to the blower to double check before dash out. Is there a relay for the motor. Have checked fuse and it’s ok.

[sapphireblack]

Is the hedgehog a good-un, not a questionable import?

[henrym3]

Marked up Behr/Bosch made in Germany

[Leslie]

I'd say that's fairly unusual if it wasn't squeaking etc before , is the battery well charged etc as funny things can happen on.low charge as we all know

[X5Sport]

The fan power connector is on the fan itself and uses a 0.5 to 8V feed from the rocker switch. Colour code is SW/GN (Mot-) and RT/GN (Mot+). Ground is via the output controller so don’t ground the motor feed as it is done in the control unit. The control point is on connector: X671 (on all engine versions).

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It is controlled from the AC control panel so the fault may be with that module.

[henrym3]

Good point, but doesn’t that suggest there is a module controlling it and if so why does it not show up on diagnostics

[X5Sport]

Sadly, not everything shows up. There may be a specific test procedure (and I don’t have any of those) to identify it. I’ve added to my earlier post. The module is the AC Panel itself. A multimeter may allow you to check the voltages - and that may tell you if the fan itself has gone. I had the one on my E53 replaced under warranty - and it squeaked loudly!

[henrym3]

The X671 I assume is the hedgehog that has 5 wires going in/out. The red has battery voltage brown is earth, can’t remember colours now but 1 moved between 0 fan off and 8v fan on full. I would be very reluctant to poke voltage at any of the wires to check if the fan runs. Looks like it’s dash out and I’d feel more comfortable doing a continuity check when I can view the fan connections. I watched a utube videos where they poke 12v at the fan once the plug is disconnected so to that end I’ll not buy anything till I can confirm one way or another. No hurry this mild weather doesn’t need hot or cold air so I have a feeling it will be put off for a while.
From an interest point, if I removed the hedgehog and switched the fan on will/should the hedgehog get hot? It is after all a resistor.
As for the fan squeaking I have no idea as I’m deaf as a post but I’m sure someone would have commented.

[X5Sport]

The voltage seems right. The final connection is on top of the fan unit and as you suspect that is a dash out job. The connection is to the hedgehog (Final/Output Stage Resistor). Input side is a BL/RT (I think BLUE with a Red tracer) wire onto Pin 3 (0.5-8V DC). Output as above Pins 5 (Mot+), Pin 1 for return (Mot-). Power feed to the FSR unit is RED with a Blue tracer

All of this lot have to be carried out:
+ Disconnect battery negative lead.
+ Remove both panels for front roof pillar.
+ Remove light switch unit.
+ Remove complete instrument carrier.
+ Remove fixture for steering column switch.
+ Remove centre fresh air grill.
+ Remove radio receiver.
+ Remove airbag module on passenger side.
+ Remove centre console.
+ Remove lower right trim from instrument panel.
+ Remove left glovebox.
+ Remove all clipped finishers (decorative strips on panel for instrument panel).

Not sure about heat as the circuit would be incomplete so no current flow. You could try poking a long Nylon cable tie through the centre air vent to see if you can move the fan in case it’s stuck for some reason. The power goes to Plug 1 below.

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