BMW 530i 2003 E39, heater fan won't turn off.

[TonyNorton600]

Hi all,

Heeeeelp please, I'm getting desperate.

My problem is a weird one. My heater/aircon fan won't turn off, even when the ignition is off. The only way to stop it is to disconnect the battery!

Logic tells me that it is a NO (normally open) contact on a relay that has welded itself shut due to high current passing through the contacts.
Only problem is, I haven't a clue where the relay might be found.

Has anybody else had this problem, or can someone please tell me where the relay for said fan is located. If I could get to it, I could probably effect a temporary repair. I have taken relays apart in the past, to clean contacts etc. but first of all one needs to know where the bleeding thing is!

Even if nobody has had this problem, the location of the relay would be a good start. If I could remove it altogether that would be a bonus, or even perhaps remove the fuse that supplies it. Can anyone tell me which number fuse that would be? There's a super list of fuse numbers for the back end of the car but I can't find anything for the front end.

Thanks in advance for any offers of assistance.

Tony Norton

[shtu]

https://forum.bmw5.co.uk/topic/33283-what-are-the-...

[kiethton]

Yeah that's the hedgehog, almost a consumable on the E39 - located under the dash, accessible from the passenger footwell f you have girls hands IIRC

Often best to get an OEM replacement as the pattern parts are never much cop and its a fairly cheap part anyway

[TonyNorton600]

Now I understand why everybody (except me that is) refers to it as a "hedgehog".

Thanks Shtu for giving me the link to Magnus's diagram.

Only problem now is, how do I get to it? I'm afraid "under the dash in the passenger footwell" isn't nearly explicit enough for an old buffer (manufactured prior to the start of WW2) like me. Could somebody who's done the job please give me some more detailed instructions, please, pretty please.

Tony N

[d_a_n1979]

TonyNorton600 said:

Now I understand why everybody (except me that is) refers to it as a "hedgehog".

Thanks Shtu for giving me the link to Magnus's diagram.

Only problem now is, how do I get to it? I'm afraid "under the dash in the passenger footwell" isn't nearly explicit enough for an old buffer (manufactured prior to the start of WW2) like me. Could somebody who's done the job please give me some more detailed instructions, please, pretty please.

Tony N

Hi Tony

Buy this: https://www.amazon.co.uk/HEATER-BLOWER-RESISTOR-GU...

It's under the dash, drivers side.

Undo the cowl under the steering wheel (x2 small screws); undo the small 8/10mm bolt that you can see thats on the transmission tunnel in the drivers footwell; slide that panel towards the handbrake and it'll unclup (there are 2 clips, so careful you don't break them).

Look into the cavity behind the control panels and you'll see a lot of wires, you need to look for about 3/4 thick wires bunched together, that lead into a large plug, that's plugged into the FSU 'hedgehog'. Pull that plug gently and the FSU will slide out, unplug, plug in new one, refit and put the other bits back.

That should be it all sorted

Here's an easy to follow how-ton on The Tube:

https://www.youtube.com/watch?v=rB1XMzVtdno&t=...

[TonyNorton600]

Hi Dan,

thanks for the info. I should perhaps have watched the video before diving in, then I wouldn't have broken one of the clip mountings. Bit of bodging needed there.

Hunting around, with the help of Google, I actually found a video of the job being done on an RHD model: -

"https://www.youtube.com/watch?v=gcXxPagSO_A".

I still have a question though, as it's going to be a few days before I get the replacement. Working on the assumption that the FSU is, effectively, a thermal switch, do you think it would be OK to run with FSU disconnected for a while? I know I would certainly get no fan at all, but that would be preferable to having to dive into the boot every time the car is going to be stationary for any length of time, and I do have windows I can open while the weather is as hot as at present.

What do you think?

Cheers

Tony N

[helix402]

A genuine BMW hedgehog will last longer than an aftermarket one. Even a used one may last longer than a non gen aftermarket part.

[d_a_n1979]

helix402 said:

A genuine BMW hedgehog will last longer than an aftermarket one. Even a used one may last longer than a non gen aftermarket part.

Zero issues with Meyle stuff and the FSUs...

Plenty of folk have used them & they’ve lasted years without fail.

I agree the stty £15 eBay jobbies are you be avoided, but Meyle are a respected brand

[d_a_n1979]

TonyNorton600 said:

Hi Dan,

thanks for the info. I should perhaps have watched the video before diving in, then I wouldn't have broken one of the clip mountings. Bit of bodging needed there.

Hunting around, with the help of Google, I actually found a video of the job being done on an RHD model: -

"https://www.youtube.com/watch?v=gcXxPagSO_A".

I still have a question though, as it's going to be a few days before I get the replacement. Working on the assumption that the FSU is, effectively, a thermal switch, do you think it would be OK to run with FSU disconnected for a while? I know I would certainly get no fan at all, but that would be preferable to having to dive into the boot every time the car is going to be stationary for any length of time, and I do have windows I can open while the weather is as hot as at present.

What do you think?

Cheers

Tony N

Absolutely fine to run the car with it unplugged Tony. You just won’t have heater controls, no big deal though, not as if it’s mid winter

Get yourself onto the 5 forums too, it’s a dedicated 5 series forum & with a very solid E39 community and knowledge base

[TonyNorton600]

Well, I finally found the hedgehog and removed it, that's a pain in the **** for an old man like me, in fact a pain in the everything. However, it's a treat not to have to disconnect the battery every time I park up.

In no way connected, but symptomatic of how **it happens, the PDC played up. Hooked up the BMW Scanner 1.40, and my steam driven laptop with XP OS, to reveal a problem at the the "Front offside". Wish they would define whether this is the inner or the outer sensor, so I have ordered 2 just in case.

One final question for you "d_a_n", where do I find the "5 forum". I can only find "BMW General" on the website.

Thanks to all who contributed valuable comments and advice. It is much appreciated.

Tony N

[naturalaspiration]

Turn the PDC on manually and then listen to each PDC sensor. The one which is not clicking click is the one to replace.

[jas xjr]

TonyNorton600 said:

Well, I finally found the hedgehog and removed it, that's a pain in the **** for an old man like me, in fact a pain in the everything. However, it's a treat not to have to disconnect the battery every time I park up.

In no way connected, but symptomatic of how **it happens, the PDC played up. Hooked up the BMW Scanner 1.40, and my steam driven laptop with XP OS, to reveal a problem at the the "Front offside". Wish they would define whether this is the inner or the outer sensor, so I have ordered 2 just in case.

One final question for you "d_a_n", where do I find the "5 forum". I can only find "BMW General" on the website.

Thanks to all who contributed valuable comments and advice. It is much appreciated.

Tony N

The forum Dan refers to is not on ph . Just Google it. There is also an active forum on facebook

[d_a_n1979]

naturalaspiration said:

Turn the PDC on manually and then listen to each PDC sensor. The one which is not clicking click is the one to replace.

Not always the cure though. One can go and cause all sorts of funny buggeryness... a good start though.

They’re only £12 each, brand new on eBay & with 2 years warranty. Worth replacing the 2 outer ones minimum, front & rear as these tend to fail first for some reason

[d_a_n1979]

TonyNorton600 said:

Well, I finally found the hedgehog and removed it, that's a pain in the **** for an old man like me, in fact a pain in the everything. However, it's a treat not to have to disconnect the battery every time I park up.

In no way connected, but symptomatic of how **it happens, the PDC played up. Hooked up the BMW Scanner 1.40, and my steam driven laptop with XP OS, to reveal a problem at the the "Front offside". Wish they would define whether this is the inner or the outer sensor, so I have ordered 2 just in case.

One final question for you "d_a_n", where do I find the "5 forum". I can only find "BMW General" on the website.

Thanks to all who contributed valuable comments and advice. It is much appreciated.

Tony N

Sorry Tony, it is a bit of a faff, you want to try being the width I am and do it haha

FYI; 5 forums here: https://forum.bmw5.co.uk/

[TonyNorton600]

Hi Dan,

thanks for the link.

Found a strange thing. You'll remember that my PDC went wonky, so I replaced both the front offside sensors, but it made no difference. So I thought "I wonder". When I removed the largest panel from beneath the steering column I disconnected the sounder that is fitted in it. So I removed the sounder from the panel and reconnected it. Bingo! Scanner 1.40 now reports "PDC no errors" and the PDC is working perfectly. Funny how the absence of what one would think of as a minor component affects something basic.

My hedgehog arrived early afternoon yesterday (Friday), but intermittent rain has delayed fitting until today. Will report back when done.

Cheers
Tony N

[d_a_n1979]

TonyNorton600 said:

Hi Dan,

thanks for the link.

Found a strange thing. You'll remember that my PDC went wonky, so I replaced both the front offside sensors, but it made no difference. So I thought "I wonder". When I removed the largest panel from beneath the steering column I disconnected the sounder that is fitted in it. So I removed the sounder from the panel and reconnected it. Bingo! Scanner 1.40 now reports "PDC no errors" and the PDC is working perfectly. Funny how the absence of what one would think of as a minor component affects something basic.

My hedgehog arrived early afternoon yesterday (Friday), but intermittent rain has delayed fitting until today. Will report back when done.

Cheers
Tony N

That's an ok fix; it's always good to retrace steps

Saying that; sometimes it's just contacts that cause issues, so unplugging and plugging back in can fix all sorts too

Fingers crossed the FSU replacement sorts your issues; if not (hoping it doesn't happen); the heater valve in the engine bay (on the side of the NS strut housing) can stick open and cause a battery drain. That's an easy DIY replacement too if it's needed, £56 for the new part via eBay and 10mins of undoing, swapping out and redoing

[pits]

TonyNorton600 said:

Hi Dan,

thanks for the link.

Found a strange thing. You'll remember that my PDC went wonky, so I replaced both the front offside sensors, but it made no difference. So I thought "I wonder". When I removed the largest panel from beneath the steering column I disconnected the sounder that is fitted in it. So I removed the sounder from the panel and reconnected it. Bingo! Scanner 1.40 now reports "PDC no errors" and the PDC is working perfectly. Funny how the absence of what one would think of as a minor component affects something basic.

My hedgehog arrived early afternoon yesterday (Friday), but intermittent rain has delayed fitting until today. Will report back when done.

Cheers
Tony N

E39 PDC systems can be a nightmare, my favourite being a PDC unit failing which kills all the dashlights, radio and aircon.

[TonyNorton600]

Hi Dan,

many thanks for your help with this, and to all others who chipped in with useful comments.

Everything seems to be satisfactory, heater controls OK, PDC OK.

Scanner 1.40 reveals: -

3 DME errors, 2 off exhaust temp before Catalytic convertor,signal short to negative, and 1 off ditto after Cat.
2 SRS errors, 1 off power supply undervoltage, not surprising as ignition was ON and fan running, but engine NOT; and 1 off Fault lamp short to negative or open circuit, probably this latter, just a blown bulb.

I've no intention of giving myself more work chasing the location of the above, as the car is running sweet as a nut.

Once again, thanks to all.

Tony N

[d_a_n1979]

Glad you're all sorted Tony

Time to drive it and enjoy it