Webasto

Bobbyjust · Feb 3, 2024

Hello good morning ,
Range Rover L322 Mk111 TDV8 4.4 2012 :
I am trying to sort out a fault with the Webasto auxiliary heater.
works perfectly on remote fob to start and stop .
when engine is at running temperature and I turn ignition off when the magic eye (hazard switch)
goes out high pitched buzz from the Webssco heater though it’s trying to start but can’t. This causes battery parasitic drain. If I turn heater on with remote then turn off ignition engine stops and the heater kicks in . then stop heater with the remote It shuts down normally and no Parasitic drain.
i am wondering could it be a water temperature sender at fault my reason for thinking this is why would the heater try to start when engine temperature normal and ambient temperature above 4c .
I would be very interested to know if anyone has had the same issue.
cheers Bob.

marjon · Feb 3, 2024

Welcome

Bobbyjust said:
I turn ignition off when the magic eye (hazard switch)

Sorry what light "magic eye"?

Bobbyjust said:
goes out high pitched buzz from the Webssco heater though it’s trying to start but can’t. This causes battery parasitic drain.

So its trying to start? or is it cooling down "mode"? although it should have stopped if you have taken it for a run.
Does it actually drain the battery so it wont start?

If folks dont come back to help you may be better asking in the range rover section as it may get more coverage.

J

Bobbyjust · Feb 3, 2024

marjon said:
Welcome

Sorry what light "magic eye"?

So its trying to start? or is it cooling down "mode"? although it should have stopped if you have taken it for a run.
Does it actually drain the battery so it wont start?

If folks dont come back to help you may be better asking in the range rover section as it may get more coverage.

J

Hi MarJon
thanks for reply .
on my car the hazard light switch has a triangle that stays on red when ignition off exit car and lock doors. The red light goes off after about 4 to 5 minutes Refered to as Magic eye ( same on Audi).This indicates that there is no power drain.
because the Webasto is wired to run without ignition on the intermittent fault high pitched buzz if left yes it will flatten the battery.

marjon · Feb 3, 2024

Ok, so its the sign the car systems are shutting down.
Are you sure its the webasto buzzing? Although your way to stop it seems to lead to it.

I cant be much help as ours works fine sorry.
@backinblack may have some insight although you are rather new.

Do you have any diagnostics available?

J

Hicap phill · Feb 3, 2024

Normally webasto won’t fully drain battery as the system won’t allow. I think the buzzing is a sticking relay, unsure which one though

Bobbyjust · Feb 3, 2024

Hicap phill said:
Normally webasto won’t fully drain battery as the system won’t allow. I think the buzzing is a sticking relay, unsure which one though

Hi Phill,
thanks for your reply .
i think you may be right do you know if the heater unit itself has a relay built in ? It does sound it’s coming from the area of the top of the heater .

backinblack · Feb 3, 2024

@marjon yes I saw this but as you say it's much newer than mine.

On the older models the FBH runs high until the coolant gets above a certain temp at which point it runs at a reduced rate until it's needed again. It will run on for a few minutes after the engine is switched off as it goes through it's cool down cycle. May be worth pulling the FBH fuse (fuse 59 on the older models) to see if it still does it.
The FBH has it's own water pump and fan which is controlled by an onboard pcb/ecu and as said should shut down when the battery gets down to 12.2v. It should also only operate at around 6 degrees or less according to the manual although mine does work on the remote fob above 6 degrees.

Bobbyjust · Feb 3, 2024

Hi Phill,
did some more investigating and all relays check out ok in the engine bay fuse box . The buzzing seems to be coming from the right hand side battery area. The battery is Brand new Bosch after the first developed a fault and would not charge to more than 75 % but show low voltage of around 11 volts even after charging for 3 days .
I have read with water damage to the Webasto transmitter in the rear fuse box. Remote works fine and when it’s running the tickin of the fuel pump is clearly heard. Looking at live data on my diagnostic the is an ambient air temperature sensor fault . the ambient out side temperature reading is displayed as correct when I checked it .
dark out there now , so have another play tomorrow.
thanks Phill kr Bob.

backinblack · Feb 3, 2024

The FBH is under the battery so sounds about right.
Is the fuel pump still ticking after the engine is turned off?

Webasto

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