[P38HSE46]

I discovered two spliced wires that go into the instrument panel, most probably for the Webasto heating system.

I removed both, as I could hear a faint sound coming from the instrument panel (like a small electric motor).

Upon removing both splices, the noise went away, but my instrument panel has lit up like a Christmas tree.

When I ground one of the wires again, the instrument panel works normally again, but the sound returns - which I suspect is draining my battery.

Any ideas as to why this is happening?

I suspect the preheating system was connected to the BCEM as well... I just hate aftermarket upgrades.

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[Dtoyne]

Does this sound only occur when the ignition is on? If so it is most likely the aspirator for the HEVAC (located to the left side of the centre dash unit). It is supposed to run, it is a little fan drawing in air over a thermocouple to let the HEVAC know what the cabin temp is.

If the noise is actually coming from the binnacle, then look for a squirrel in a cage! There is nothing there that can give that noise.

 

[P38HSE46]

It is coming from the instrument panel itself, but only when I ground one of the wires in the main plug connector going into the instrument panel.

If I remove this ground, the sound disappears, but the entire panel lights up like a Christmas tree.

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[P38HSE46]

Could it be that this ground should be controlled by the BCEM and should only come on when started?

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[P38HSE46]

 

[Richard_G]

There is no motor behind the instrument panel, as mentioned there is the aspirator for the HEVAC in the centre of the dash and there are the blend motors that are a little closer, You need to delve into the ETM a little deeper and check where these additional wires are attached, Only ever seen a Webasto pre-heater on a diesel, not a petrol.

 

[P38HSE46]

The two wires that have been spliced are Black Green, both of which go to the BECM.

The sound that is coming can very well be an aspirator, but I assume it should not be running when everything is switched off.



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[Richard_G]

Does it stay running? There's an ignition switched supply that remains live for 30 seconds after you switch the ignition off. Amongst other things it is the positive supply to the fuel injectors but is often used as a supply for aftermarket add-ons (my LPG ECU is powered off it). A pair of Black/Green wires going to the BeCM doesn't help a lot, there's 17 multiway connectors going into the BeCM and I suspect quite a few will have a Black/Green wire.