Webasto Pre Heater & Alarm sensors.

[Andy.]

Sometimes when I run my pre heater the alarm is activated by the blower once in operation. It seems to trigger off the overhead sensors by the blower.

I have the blower set to speed 2 as this is the best option.

I have seen this "Alarms, it maybe necessary to isolate the ultrasonics of the alarm, depending on type fitted. This generally involves using a change over relay to break the ultrasonic connection. The trigger wire to the relay can be taken from the fan relay signal. Use same type relay".

How do I go about wiring a relay in

[Matt_H]

you'd need to work out if you can cut the feed to the sensor without setting the alarm off first.  

If you can and you can work out which one to cut (note you'll need to cut it from all sensors unless there is one main ultrasonic connector on the alram control) then you need a change over relay

you can find a 5 blade changeover here

http://www.vehicle-wiring-products.co.uk/VWPweb2000/relays/relays.html

using the diagram to go by wire the connectors as follows

30 sensor feed
85 fan + when running
86 ground
87 nothing (unless you want a nice warning light)
87a other side of sensor feed where cut

[Paul]

Andy,

Try this... Cover the interior sensors with insulation tape so that they
can't see anything, Set the webasto to come on in say 5 mins and
lock it up using the alarm.

Doing this will tell you if the alarm is sencing the air movment in the
vehicle or the voltage drop when the heater motor starts up.

[Andy.]

Cheers Paul will give it a go.

[Andy.]

you'd need to work out if you can cut the feed to the sensor without setting the alarm off first.

How can I tell this  :?:  

If you can and you can work out which one to cut (note you'll need to cut it from all sensors unless there is one main ultrasonic connector on the alram control) then you need a change over relay

According to the work shop manual, there is one main ultrasonic sensor module connected to the alarm ECU.
The rest of the alarm is made up of a bonnet switch, door switches, the lock barrel and sill buttons.

If I can cut the feed :?: there are two sensor wires going to the ECU so these can be wired to the relay unit  :?:

There is a connection in the work shop manual wiring diagram for a Fuel burning heater unit to the ECU to I presume LR pre thought of this problem  :?:

And where is this ECU the manual has it down situated in the steering column is this correct  :?:

[96Disco]

I've had the same problem, after some experimentation I've found that setting the blowers to use the dashboard and footwell vents (rather than the screen and footwell vents) doesn't trigger the alarm.

Best regards,


Phil.

you'd need to work out if you can cut the feed to the sensor without setting the alarm off first.

How can I tell this  :?:  

If you can and you can work out which one to cut (note you'll need to cut it from all sensors unless there is one main ultrasonic connector on the alram control) then you need a change over relay

According to the work shop manual, there is one main ultrasonic sensor module connected to the alarm ECU.
The rest of the alarm is made up of a bonnet switch, door switches, the lock barrel and sill buttons.

If I can cut the feed :?: there are two sensor wires going to the ECU so these can be wired to the relay unit  :?:

There is a connection in the work shop manual wiring diagram for a Fuel burning heater unit to the ECU to I presume LR pre thought of this problem  :?:

And where is this ECU the manual has it down situated in the steering column is this correct  :?:

[Andy.]

Cheers Phil.

I've set it again tonight but this time with Pauls tip so we'll see what happens  :?:

The thing is it's ran twice before since fitting and never had a problem, this time it just caught them right. The same thing happens if I leave the front sunroof open with the Discovery locked.

I also learnt tonight that some models were fitted with an output which disables the vehicle volumetric alarm when it swithes heater fan on.

Also fitted can be a cutout which switches heater fan back off if the voltage of the main battery falls below a preset point.

I've sent Webasto an email to see what they advise  :?:

On your point in may well work switching the vents, but the whole point is to have the vents on the windscreen to demist/defrost on a frosty morning.

We shall see  :?:

[Gary]

Hi Andy

do you have anything in your vehicle that can be moved when the fan cuts in ie a hanging air freshner from the rear view mirror or god forbid fury dice  :lol:   :roll:

It may be that something moves in the vehicle when the blowers activated and then the ultrasonic will pick that up. They pick up on movement rather than changes in heat. They are not PIR's (Passive Infra Red detectors) as you would use on a conventional house alarm which pick up changes in heat patterns.

Having said that they may be sensitive enough to the actual movement of the air.

It's just a thought mate.....something else for you to consider.

I would be reluctant to cut into the cable feeding the ultra sonics because the wires in side the cable are relatively fine and fragile. I'm not sure that they operate like a conventional house hold alarm detection zone where you would have 12v pos + Neg - and 2 pairs of Normally closed loops, 1 being a 24 hour tamper loop and the other being Alarm activation loop, which would be easy to use a relay to short out a Normally open circuit from an Alarm activation.

There must be another way round this. I'm sure webasto/eiberspacher and I'm assuming your alarm system is a genuine LR unit will have the relative in/outputs to overcome this liitle problem. Get on to both respective technical departments to find out all your options b4 cutting into the ultrasonic/s cables.

Kind Regards, Gary

Oh BTW I use to design and install bespoke commercial/industrial security systems.
These are different from the vehicle security systems but I have a friend who specialises in Thatcham acredited vehicle security systems. If you need more help I could give him a quick call to find out if you have no joy.
He installs theft prevention alarms and phone systems for our local LR dealer in Canterbury. He's always really busy so I'll only try if you have no joy your end.

Good luck and if you need some extra help just email me and I'll track my mate down for you.  

gary@n-gage4wd.com

[NeilWilson]

I had my alarm go off a few times with my Webasto just after I had installed it.  I now use the fan speed setting 1 & the screen vent setting.  Hasn't happened again.  I did contact Webasto & somewhere I have a pdf of a circuit change for fitting an alarm sensor relay to isolate the ultrasonics.  Although the pdf is for a Defender the ciruit is the same.  If I find it I will post it.

Neil

[Andy.]

Now then Gary you might have something there  :idea:

I have an Evil Duck hanging from my rear view mirror. This is my second unit and it never happened with the first and no evil duck too. I tried Pauls tip last night and no alarm this morning so I think the duck has to go, will try it and see  :?:

Got a reply back from Webasto and received the same circuit change pdf file Neil and yes it's for a Defender system but if all else fails looks simple enough to install but would rather not.

I'll monitor it over the next few cycles, cheers everyone for your input  

[Gary]

your welcome Andy

glad to be of some help mate  

I will follow this thread with interest as a webasto unit is on my wish list and I to have an alarm system on my defender.  :roll:  Mines not a LR alarm so I can possibly see some investigation will be needed when I eventually go down the same route.

Regards, gary

[Andy.]

The pdf file that Webasto sent me is for a TD5 Defender, if you want I can send it too you  :?:

Just PM me your email address and I'll send it.

[Andy.]

Well tried the heater without the duck and it still sets off the alarm.

I could turn the blower setting down to one but I think this will be less effective on a cold frosty morning. Or install a relay as Webasto have said, but don't really want to mess around with the alarm wires.

One more option to try is that whenever I want to use the heater I lock the motor with the key rather than the remote. This way I arm the vehicle with perimetric protection and this turns off the ultrasonic unit. When arming with the handset you activate the volumetric protection with the sensors armed.

In fact I do have a LRSS alarm system to fit, had it for over a year now  :shock:

[Andy.]

Just another thought too, by using the key and arming the vehicle via the perimetric protection am I not doing exactly what a relay would do  :?:

I would only use the key for when I wanted to use the pre heater, all other times I would revert back to the remote and again arming the sensors.

[Gary]

Hi Andy

that's a bummer it wasn't just a case of removing the hanging item from your mirror  :(

Are you saying that when you manually lock your vehicle with a key that it activates the central locking AND "part-sets" the alarm system?

Is your alarm Cat 1, does it have an engine imobiliser built in with it?

If so, does the imobiliser activate automatically after a pre-set time or would this be actiavted by either the use of the Remote Alarm Fob or the use of the key to lock the car?

I'm just curious to see how your Alarm system operates or how it has been set up.

I'm trying to determine for you if your vehicle will be less secure if you choose to lock it manually with a key so you can operate the Pre-heater  :roll:

Also, if you choose to lock your vehicle with the key only the night before so your Pre-heater can cut-in in the morning without a false actvation of the alarm......I presume you could still you your Remote fob to unlock the vehicle in the event that the weather was that cold that the door lock might be frozen  :shock:

having said that.............

It would be nice to presume that the Pre-heat system would allow a defrosting of the engine, cab area and the door lock mechansim  

gary

[Andy.]

Hi Gary.

My anti theft alarm system is factory fit by LR. It basically has two setting.

Perimetric protection using the key will arm all doors, tailgate, and bonnet and cranking is also disabled. This method disables the ultrasonic sensors when the vehicle is locked.

Volumetric protection using the handset remote (key fob) protects the interior using the ultrasonic sensors and also arms and disarms the vehicle perimetrically and cranking again is disabled.

Now because the blower is setting off the sensors they need to be turned off.
I could like I've said on a night use the key and disable the sensors and pre set the heater for the morning. This however would leave the interior vunerable over night until I return to the vehicle. If someone smashed a window the sensors would not be armed to detect this.

Or as Webasto have said fit a relay into the sensor circuit connected to the pre heater fan relay. This way the sensors would only be disabled for 30 minutes while the heater is in operation, throughtout the night they would be armed as normal.

The reason for the key method is so you can lock the vehicle whilst passengers like the kids or pets are inside and they will not set off the alarm.

The pdf wiring diagram I sent you seems straight forward enough to follow and I have ordered a suitable relay. I will this wekend have a closer look at the set up and examine the wiring in view to installing a relay.

To answer one of your questions, yes the motor will be less protected using the key method as opposed to the key fob.

Hope that clears a few things up, good fun this LR ownership  :lol:

[Gary]

Hi Andy

Your right, it is good fun this Land Rover ownership, there's never a dull moment !  :)

How have you got on with fitting that relay mate.

I'm curious Andy, how many wires are there in the cable going to your ultra sonics?  :roll:

Regards, Gary

[Andy.]

Sorry Gary not had chance today been fitting a reversing aid instead.

I've just ordered some stuff from VWP for my split charge set up so I thought while I was doing that order a relay for the alarm. Should be here early next week.

Will keep you posted  

[Andy.]

Right been changing some interior bukbs this morning, however when placing back the digi timer for the pre heater I accidently pressed the instant heat button.

Now before I had to have the blower set, this time the blower was off on the panel. But because of the way it is wired the pre heater relay auto activates the blower on start up.

The last pre heater I had it was wired to number 2 setting on the blower and I had no alarm issues, this time it auto comes on at blower speed 3 which I guess is why the sensors are going off.

So I could revert back to the number 2 blower setting, but I do like it as it is now, as it's lovely and warm inside and it is using the maximum blower speed to warm the cab up.

So now I've found the problem, it's on to solving it.

I have taken the sensor panel off the head trim today and there are 3 wires for the sensors. Earth, White/Black wire and a Brown/Black wire. the second two both go to the alarm ECU.

Now according to the Webasto pdf file I got it's says the relay should be connected to the White/Black wire for the sensors. Still intrigued though as to this fuel burning heater unit connection on the main alarm ECU.

And just out of interest could someone else confirm where the alarm ECU is located on a 200 series Discovery  :?:

[Andy.]

Right well the relay is in. Fitted it this afternoon, bit tricky wiring up the sensor wire due to there location but apart from this very straight forward if you follow the Webasto pdf wiring diagram.

Once installed I tested the relay. Set the pre heater going and it ran it's full cycle without the alarm going off.

Tested the sensors after whilst sitting in the motor and they worked fine.

Cheers for the advice given and if anyone wants the pdf file send me a PM and I'll send it over  

Change over relay.