Need help identifying fuse circuit

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Northman
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Need help identifying fuse circuit

Post by Northman » Wed May 17, 2017 12:15 pm

Hi

Z4 roadster '08 is popping a 5A fuse when the engine is running and the climate system switched on. It's fuse 10 on the diagram below. Now the odd thing is, that when the climate system is off, everything else works fine (locks, interior lights which are on the same fuse). Once the fuse has popped, I have no door locks, interior lights, windows etc. The heating system seems fine though, blower and temperature controls work!

In the fuse diagram fuse 10 seems to cover an item with a thermometer which I assume is the part causing the problem, but I can't seemt o identify it. Can anyone tell me what part of the climate control system it refers to?

Thanks
z4 fuses.jpg
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Scooba_Steve
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Need help identifying fuse circuit

Post by Scooba_Steve » Wed May 17, 2017 5:44 pm

Which setting pops it on the climate? Most units in the car have their own boards, so the climate control could be faulty. Code read may help, you anywhere near London?
Also, stop doing whatever causes the fuse to blow, don't keep replacing it.
3.0si Sport: F10 Illuminated ZHP, Retrofit Cruise, OE Stubby, Gaptech RCH+, Kenwood BT73DAB + Handsfree, HIDs, LED Sidelights, OE LED Number Plate Lights, Custom LED strip bootlight.

Northman
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Need help identifying fuse circuit

Post by Northman » Wed May 17, 2017 6:57 pm

Thank you Scooba_Steve.
Nowhere near London I'm afraid - any further north and I'd be in Scotland! It took a while to work out what was causing the fuse to blow, bit now that I know we're driving with the heating off so it doesn't blow. That's only ok while the weather's good!
The fuse pops shortly after the climate system is switched on. If it's off (fan knob turned fully down, system switches off) then everything is fine. If it's switched on without the engine running, it's fine too. If the engine is running then within a few seconds of switching it on the fuse pops. The blower seems fine, but as the system registers its inputs and starts to drive up the fan/heating to adjust temperature, that's when it seems to go. I was hoping it would be a temperature sensor or a short somewhere. A circuit board on the climate control sounds expensive!

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kis
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Need help identifying fuse circuit

Post by kis » Thu May 18, 2017 10:30 am

Rare '15 Plate E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 320ci, E46 M3, E90 (x2)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
X5 - E53, E70
X6 - E71
7 Series - E32

Scooba_Steve
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Need help identifying fuse circuit

Post by Scooba_Steve » Thu May 18, 2017 2:18 pm

I would like to think that some error codes would be stored for the heater to confirm it.
What other settings cause it, I.e. Is auto air distribution on? Does it do it at any temperature setting?
I'm not sure if the heater controls are interchangeable without coding but if they are them swapping with a know working unit could be worth a shot. If you did need a replacement then breakers would be a good staring point.
3.0si Sport: F10 Illuminated ZHP, Retrofit Cruise, OE Stubby, Gaptech RCH+, Kenwood BT73DAB + Handsfree, HIDs, LED Sidelights, OE LED Number Plate Lights, Custom LED strip bootlight.

Northman
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Need help identifying fuse circuit

Post by Northman » Fri May 19, 2017 11:32 pm

There are a couple of places locally that may be able to run the diagnostics, I'll try them. I checked with and without the 'auto' on, and it blew in both cases. I've not tried temperature variants, may have a chance over the weekend.

I'm still puzzled that the airco unit still runs once the fuse has blown. Hence my original question as to what component is indicated by the thermometer in the fuse diagram.

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Need help identifying fuse circuit

Post by Scooba_Steve » Sat May 20, 2017 4:15 pm

I'll have a look on WDS
3.0si Sport: F10 Illuminated ZHP, Retrofit Cruise, OE Stubby, Gaptech RCH+, Kenwood BT73DAB + Handsfree, HIDs, LED Sidelights, OE LED Number Plate Lights, Custom LED strip bootlight.

Northman
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Need help identifying fuse circuit

Post by Northman » Tue Jun 06, 2017 1:24 pm

I've now had a chance to have the problem looked at by a local independent. They reckon it's the auxilliary water pump on the heating system. Once that's disconnected then the fuse stops blowing. They've suggested we can have a new one fitted, or run without it connected. Any thoughts?

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Need help identifying fuse circuit

Post by Cookie » Tue Jun 06, 2017 2:30 pm

From the diagram you have here and the previous post fuse 10, only covers your immobiliser, interior light and or lougage conpartment light. Can't see why this should trip with climate control or water pump. Are you sure you have the right ID number from the fuse box?
CookieP

Northman
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Need help identifying fuse circuit

Post by Northman » Tue Jun 06, 2017 3:42 pm

Hi Cookie, quite sure it's 10; I've changed it often enough! I gather the auxilliary pump comes in if the engine is idling so there's not enough heat coming through the system. It boosts the heating. I'm guessing that the symbol at the bottom of the left had column in the above diagram is a thermometer, so linked somewhere along the line to sensing low temperature and bringing in the auxilliary. I may of course be wrong, but it seems to fit.

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