E46 hedgehog idiots guide

[Tamworthbay]

As I know a few people on here have E46s and the seemingly inevitability of swapping this out I thought I would do a quick guide.

 

1 have a beer

2 have another

3 take off the lower dash panel, three screws, one thumbscrew behind the pedals and a lift the dot fastener on the tunnel

4, pull it towards you and down. Then disconnect the sireny thing and light, the OBD connecter comes off if you slide the grey bit and push it through from the other side

5, remove anyone who is easily offended from the vicinity

6 kneel outside the car and somehow get your head sideways onto the carpet and look up towards the middle of the car, lighting the area is essential.

7 remove the screw at the bottom of the hedgehog that you can see

8 swear a lot

9 swear some more then realise you need a mirror or endoscope to see the sneaky fecker of a second screw

10 remove it

11, wiggle out the servo and disconnect the arm

12, there is a flap of plastic towards the front of the hedgehog, push this to one side while wiggling put the hedgehog (don’t disconnect it yet as it gives something to hold onto) at this point you will be cursing god for only giving you two arms, neither of which comes out the from the middle of your head

13, swap out the hedgehog and replace Haynes style except leaving out the top screw, that little git isn’t needed anyway

14 sit back and endulge a sense of smugness whilst applying tcp to your wounds.

[HMC]

About to collect an e46 this Friday, good timing!

[Tamworthbay]

About to collect an e46 this Friday, good timing!

They are notorious for going dodgy, any weirdness with the air con/ heater motor and chances are this bit is blame. It’s not as bad as some people would have you believe but it is a ball ache.

[garbaldy]

What's a hedgehog and do I need to worry.

[NorfolkNWeigh]

Or just buy an e39.

1. Remove plastic panel next to clutch.

2. Push aside plastic clip.

3. Slide out Hedgey The Hedghog.

4. Disconnect.

5. Reverse in the Haynes style ( Don't bother with plastic clip, just push the trim back to hold it)

 

No swearing, takes about 7 minutes, 5 if an auto.

[Lord Sterling]

Er yes, whats a Hedgehog? I'm unsure if I have one in my e46.

[Tamworthbay]

Er yes, whats a Hedgehog? I'm unsure if I have one in my e46.

It’s proper name is the final stage resistor and it controls the speed of the heater fan, it’s a solid state rheostat basically and if you have air con you will have one.

[Lord Sterling]

It’s proper name is the final stage resistor and it controls the speed of the heater fan, it’s a solid state rheostat basically and if you have air con you will have one.

Ah cool, I do have aircon but it needs regassing. I could have done with it in summer but hey ho, no need for now...

[Tamworthbay]

Ah cool, I do have aircon but it needs regassing. I could have done with it in summer but hey ho, no need for now...

It controls the heater motor, but if you don’t have air con it’s a different system (or so I believe) and you don’t get one, so if the fan does weird stuff like changing speed when it shouldn’t or if it doesn’t go at all then hedgey is fooked.

[r.welfare]

Is there only two screws? I'm sure I removed three on my brother's coupe and it still wouldn't come out, leading me to conclude it was held in by four but I couldn't find the last one for love nor money.

[Tamworthbay]

Is there only two screws? I'm sure I removed three on my brother's coupe and it still wouldn't come out, leading me to conclude it was held in by four but I couldn't find the last one for love nor money.

Only two, one is easy to see, the other is a sod. You can’t see it because of a plastic duct in the way and the steering column.

 

You need a T20 torx bit of the right length, not too long or too short. Probably easier on lad cars as there wouldn’t be the steering column in the way.

[spike60]

As a serial E39 hedgehog replacer I can advise you can similar symptoms, (heater fan randomly running when car switched off), can be  from the heater control unit in the dash. The guilty one has a diesel fired aux heater, perhaps this was part of the problem but changing the heater dash control unit solved it.

[richardthestag]

you chaps should think yourselves lucky

 

the "hedgehod" on a RR Classic controls everything except full speed blower.

 

It is helpfully located on the outside of the bulkhead but under the deck panel in front of the windscreen. 

 

Option A. many with smoller hands than me remove the fresh air vent on the front of the deck panel and squeeze their hand and wrist through. Many have ended up in A&E with awkward to explain wrist cuts from the sharp edges of alluminum/birmabrite whatever.

 

Option B. So to remove the deck panel, remove 4 bolts, washer pipework and loom so the bonnet can be removed. Heaviness is involved so help is needed here.

 

Remove two wipers, remove half a dozen or so screws from captive spire nuts that will be a seized, rusty, solid unit. I find that a hearty good tap from #3lb hammer on end of a screw driver carefully positioned on the washer of the offending screw will get stuff moving. Bent ally can be straightened later

 

Then two screws need removing from the trailing edge of the deck up against the a - post accessible by opening front doors and working forwards

 

Then simply remove 4 10mm bolts that secure the deck panel to the top of the front wings, two are piss easy, two will involve creative use of expletive. you may need several rest breaks. I have found the finest toothed ratchet arm known and can swing that 3cm with just about 4 clicks of the ratchet.  There is not enough room between the outer skin of the deck panel and the side of the bulkhead to squeeze an adult hand in holding the end of the ratchet to position it on the bolt head. After much hit and missage and then removing to change the direction of the ratchet I might have been known to promise an increase in pocket money for one of the youngling thestags smoll hands.Often the bolts will be tight for some reason. I have a 2ft iron plumbing pipe that fits over the end of the ratchet arm to "encourage" movement. when is does start moving you have a 3cm swing on the ratchet and the bolt is 2cm long with quite a fine thread. you will bash the back of your hand against the sharp edge of the deck panel about 7265times with boths sides to take into account

 

At this point you can remove the deck and probably launch it over several garden. Note this could be the final straw for your thus far tolerant neighbours.

 

You are now faced with the offending item, it is secured on a bracket against the bulkhead. two screws secure it to the bracket. these are rarely difficult to undo. but a right faff if working through the letterbox on the front of the deck and slashing your wrists.

 

The connector is on the other side of the bulkhead and if this is the first time the job has been done you will find that the loom and connector will be trapped on the inside of the car. Luckily there is a blanking plate, removing 6 screws and the blanking plate will give you all the access you need. HOWEVER if you went for option a above - the letterbox you will now need to either go for option b or remove the dash top for access - when you get back from A&E that is.

 

Once replaced you are exactly halfway through this debacle. I cut through the deck panel flange (fnarr) which means that next time I do NOT need to remove the bonnet. There are also a few range rovers out there with just 2 bolts securing the deck to the front wing for some reason.

 

Laying upside down and using a mirror ? Luxury #4 yorkshiremen

 

 

[alf892]

On my E39 this fiendish little fucker was the cause of a very dramatic (but very intermittent) battery drain.

[John F]

I thought the thread title was alluding to the old "pricks on the inside" BMW joke.

[The Reverend Bluejeans]

E36 Hedgehog:

 

Remove glovebox (six screws)

 

Remove hedgehog on passenger side of heater box (two screws) and fit another one.

 

Refit glovebox.

 

 

Sorry.   

[Ben_O]

Just done this on my e46.

 

I managed it in 15 minutes without the need for beer.

 

Piece of piss

[Ben_O]

Actually, thinking about it, Since my blower is now working, I have noticed that it just blows hot air no matter what you set it to.

 

Any thoughts?

[Tamworthbay]

Just done this on my e46.

 

I managed it in 15 minutes without the need for beer.

 

Piece of piss

Wash your mouth out, there is ALWAYS need for beer. I was expecting a complete nightmare having read a couple of threads about it but apart from being in a crappy location it’s not a killer, the only hassle is that stupid top screw that you can’t see and can’t get a decent screwdriver on due to the steering column.

[Tamworthbay]

Actually, thinking about it, Since my blower is now working, I have noticed that it just blows hot air no matter what you set it to.

 

Any thoughts?

Do you get the whirring of of the servos when you change the direction of the heat flow? I would guess that the temp is also servo controlled as there are no cables from the control unit. I have a spare control unit if that turns out be a duffer but I doubt it’s that if it powers up.

[Ben_O]

Wash your mouth out, there is ALWAYS need for beer. I was expecting a complete nightmare having read a couple of threads about it but apart from being in a crappy location it’s not a killer, the only hassle is that stupid top screw that you can’t see and can’t get a decent screwdriver on due to the steering column.

 

I was at work so beer was a no no really.

I used an electric screwdriver to dismantle and reassemble mine so made it easy to get in there including the hidden screw.

Do you get the whirring of of the servos when you change the direction of the heat flow? I would guess that the temp is also servo controlled as there are no cables from the control unit. I have a spare control unit if that turns out be a duffer but I doubt it’s that if it powers up.

I can't say I have noticed actually. Ill have a listen today when I go out later.

 

Cheers

[Tamworthbay]

Do it with the engine off or you won’t hear it.

[Ben_O]

good tip.

 

I remember having difficulty popping the rod back into it's plastic clip on that servo thing so i wonder if it's popped off or stuck?

 

If that is what controls it?

[Tamworthbay]

Not sure if that one is for the flaps or the temperature but think probably not. I presume the temperature will be controlled by a standard type valve so don’t think that servo would be the one. The matrix is up in the bowels so hard to see what does what up there. I guess the thing to do is crank up the temperature with the fan on manual and turned right down so you can hear if anything is moving. Good luck!