Why does my FBH not turn the blowers on??

[Mickyboy]

Originally Posted by first-things-first

I think you are wrong Harry. Probably depends on if you have the timer and remote switch on fitted as well?

My car (with factory FBH and timer) starts the blower with the FBH with no intervention from me. I just switch it on with the remote.

I think you may have to have left the climate on auto (before switching off engine) for it do this, IIRC ...

Yeah mine does that to I think you have to leave the temp set at something like 26°
Mick

[Pete_901]

Yeah well I’ve just had a little look at my fbh. If I leave the blowers on then turn the ignition off and turn the webasto on then the blowers come on when the webasto is turned on. But if I leave my blowers off then turn the webasto on it doesn’t come on.

I do need to order a GSM unit! How easy are they to wire up?

[trebor]

The FBH will not switch the ATC on if you leave it switched off when you leave the car it just activates it to the setting you left it on when you last exited the car

[HarryM1BYT]

Originally Posted by first-things-first

I think you are wrong Harry. Probably depends on if you have the timer and remote switch on fitted as well?

My car (with factory FBH and timer) starts the blower with the FBH with no intervention from me. I just switch it on with the remote.

I think you may have to have left the climate on auto (before switching off engine) for it do this, IIRC ...

Originally Posted by Mickyboy

Yeah mine does that to I think you have to leave the temp set at something like 26°
Mick

Originally Posted by Pete_901

Yeah well I’ve just had a little look at my fbh. If I leave the blowers on then turn the ignition off and turn the webasto on then the blowers come on when the webasto is turned on. But if I leave my blowers off then turn the webasto on it doesn’t come on.

I do need to order a GSM unit! How easy are they to wire up?

Sorry, but I still cannot see how that can possibly happen, there is no means for the ATC to get a 12v supply for it to do that.


Why would anyone go to all the trouble and lengthy discussion of a mod to allow it to operate with the ignition off, if it could already power itself up? There was even a lengthy discussion about how to delay the ATC operation, until the FBH had warmed the coolant enough to impart some heat into the cabin. There was even a short discussion about adding a secondary battery, so that using the FBH plus blower, didn't flatten your main battery.



I have had an FBH fitted for 7 years, modified for manual running to pre-heat and not once has the blower ever powered up until the ignition was turned on.


All I can suggest is that those suggesting their blowers start, have had the modification done behind the ATC panel.

[first-things-first]

I've never seen any extra "mod" wiring in my car, although it may be hidden behind the ATC.

From my user manual (facelift) :

Some diesel engines are equipped with a programmable automatic heating facility, which enables the owner to pre-heat the interior of the car (and warm up the engine) prior to use.

The parking heater will then operate until the preset running time has elapsed, heating and maintaining the car's interior at the desired temperature.

The parking heater utilises the car's interior heating and ventilation system settings ...

This specifically mentions not having to have the key in the ignition.

Therefore, the difference must be the options fitted to the factory car - early cars all have a FBH fitted to aid in warming the engine.

The cost option was to have the parking heater which gives the extra timer, remote control and interior warming facilities over a standard FBH only arrangement.

[Lovel]

Wiring diagram attached for the original factory install parking heater which runs with the engine off and will pre-heat the cabin for you and defrost the windscreen for up to 30 mins either by remote function or via the timer programmer in the armrest.

I have converted three vehicles in the past to parking heater following the manufacturers wiring and using the official components on each install, 1x75 and 2xFreelanders.

No matter how many times I have studied the official wiring diagram it does not make sense to me if you follow the relays. So I would treat the relay wiring with some suspicion, all I can say is that 99% of the diagrams are correct, but little errors occurs now and again, but on the whole they are excellent.

I would check fuse 37 (passenger compartment) first.

Then with the FBH running and up to temperature you should eventually get a 12v reading from the black/yellow wire at the FBH connector CO925-4. Or follow the black/yellow wire into the passenger Cmpt relays for the parking heater and check for 12v present there. If you have 12v then you will need to check both relays function which are located in the passenger footwell.

If the blower does not switch on the FBH will start shutting down as the heat is not being dispersed from the coolant system. This will also occur if the water pump on the side of the FBH is not functioning as ther is literally no heat soak occurring.

Another area to check depending upon if this was an original factory install or retrofit from Webasto or the owner then there maybe a number of diodes (can’t recall how many, perhaps 4?) run behind the heater ECU panel that may have failed and not allowing the heater panel to power up.

[trebor]

A simpler wiring diagram for bringing the ATC on after 5 minutes is below in the GSM "how to" , with the second relay of the GSM programmed to switch on 5 minutes after relay 1, so relay 1 starts the FBH in parking heater mode and relay 2 delays for 5 minutes before switching on the ATC

https://www.the75andztclub.co.uk/for...d.php?t=231637

[Devilish]

Originally Posted by HarryM1BYT

All I can suggest is that those suggesting their blowers start, have had the modification done behind the ATC panel.

CORRECT
Aftermarket controlling.
The wires from the ATC are severed, then a DPDT relay is connected to act as a relay, timer and a diode, so when 12v is sent to the blower motor from the FBH via the DPDT, 12v does not feed back to the IGN.

A timer relay is also installed for user to select ATC on/off times.

GSM modules and relays have developed and improved significantly, and about perfected since this thread was posted.
https://www.the75andztclub.co.uk/for...d.php?t=231637

[Devilish]

Originally Posted by Lovel

I have converted three vehicles in the past to parking heater following the manufacturers wiring and using the official components on each install, 1x75 and 2xFreelanders.

This is fine using original equipment, that is need for timed ATC function, because the Webasto sends 12v from pin 4 as soon as the FBH fires up, then the Webasto controller performs the ATC timer function.

Webasto controller equipment costing more than a 75 or Freelander is worth/cost puts people off (me anyways). Aftermarket controlling does the same job, but the fobs cost £5.

I have seen several with Webasto controlled FBH, all down to what the user wants to pay for. When I did SWMBO's Freeelander I thought of Webasto controller, until I saw the price. Yeh right.

[Devilish]

Originally Posted by Pete_901

Yeah well I’ve just had a little look at my fbh. If I leave the blowers on then turn the ignition off and turn the webasto on then the blowers come on when the webasto is turned on. But if I leave my blowers off then turn the webasto on it doesn’t come on.

I do need to order a GSM unit! How easy are they to wire up?

GSM units are relatively east to install. I ave worked with the manufacturer for a long time improving the eeprom programming ro eliminate all the bugs, and have GSM units with the latest eeprom software.

Depends upon the controller you have and how it is connected. The blowers switching on the same time as the FBH is a waste because it takes at least 5 mins for the FBH to ramp up and run long enough to pass warmer water to the heater matrix. 15 mins after running it should shut down really, or on demand.

This is one way it should be done, if it works the way the use wants job done.