FBH remote operation circuit

NikTheGeek · 30th January 2009, 14:25

I know this has been discussed to death, so apologies, but I can't find the answer I'm looking for.

I've just purchased a 12v remote switch with key fob from Maplin. I know I need to short pin 3 to make the FBH fire up as I've tested it by manually shorting pin 3 to gnd.

But: my remote switch can be set to momentary or latching switching. So a single press can turn on and another press turns off; or it turns on for the duration of the press and as soon as you stop pressing, turns off.

Which option do I need? Once its turned on, does it stay on until you disconnect pin 3? In which case latching. Or is it timed? If I use latching, will turning the engine on for a journey, then stopping override it and switch it off?

If latching, I'll have to rig up some sort of indicator too so I don't accidentally leave it on and flatten my battery...

tnx for any advice or suggestions (other than spending loads on a proper Webasto one!)

Nick

CDTi · 30th January 2009, 14:37

IIRC, the FBH only stays powered up for as along as pin 3 is grounded - try it yourself to be certain, or someone else will clarify it on here.

You could rig up a timer for, say, 10/15 minutes so the FBH will not stay on for too long. It will cut out in any event when a certain temp is reached (68 degrees?).

NikTheGeek · 30th January 2009, 14:43

Ah, ok, cheers. I'll try it. I could always rig up an LED near the wiper mounting so that I can see its on, but I didn't know it would cut out anyway. ISTR reading someone ran their battery flat leaving one on. I'll try it anyway. Maplin do a timer for £7.99 that I could get....

Nick

-Joe · 30th January 2009, 16:36

i have a meastro heated rear window timer (£7 from scrapyard). It should be just the ticket for fbh timing... If only I had an explanation of it's pin outs. Need an old haynes manual for a later model meastro used to have one..... can't find it.

NikTheGeek · 30th January 2009, 16:42

Works a treat. The remote module sits inside the battery compartment with a single small wire going to pin 3 of the FBH connector. I used an ATX power connector (from a pc) and pulled one of the female pins out and shoved it down the hole where pin 3 is. Sort of worked, a bit hit and miss, but with a bit of solder to make the hole narrower it fits electrically well now.

The key fob has a great range. Works from inside the house

If I click it, the FBH fires in to life and runs. If I click it off, it goes in to its shut-down cycle. But therein lies the problem, you don't know if you've pressed it off or not unless you hang around to check it goes off. So I still need some sort of visual indication. It might be easier to find the pin-outs of the 6 pin plug and find one that has a 12v feed when the unit is powered up and then tap a light or led in to it.

Otherwise, its playing with a timer...

tnx all for your help in various threads over the last month or so!

Nick

CDTi · 30th January 2009, 16:49

I thought about using a spare heated seat switch as an FBH timer. There is a 10 minute timer built into each switch. I think it switches the ground. You could easily add one to your dash, assuming that you haven't got all 5 slots already filled :lol:.

FROGGY · 30th January 2009, 17:31

Nick

Why not use the feed to the FBH from the Remote module to switch an LED as well? That way, even if the FBH is quiet, the LED will still be on.

Mick

raykay · 30th January 2009, 17:46

Quote:

Originally Posted by CDTi

I thought about using a spare heated seat switch as an FBH timer. There is a 10 minute timer built into each switch. I think it switches the ground. You could easily add one to your dash, assuming that you haven't got all 5 slots already filled :lol:.

There isn't a timer in the heated seat switches, they are switched off by a thermostat in the heater panel.

CDTi · 30th January 2009, 17:58

Quote:

Originally Posted by raykay

There isn't a timer in the heated seat switches, they are switched off by a thermostat in the heater panel.

There is both a timer and thermostat.

NikTheGeek · 30th January 2009, 18:05

Quote:

Originally Posted by FROGGY

Nick

Why not use the feed to the FBH from the Remote module to switch an LED as well? That way, even if the FBH is quiet, the LED will still be on.

Mick

The remote is a single channel, single relay. I'm using it to switch hot pin 3 to ground. I figure, although I haven't sat and thought about it, that if I stick an LED in, I'd have to power it, and that would cause a short over the relay.

Nick

30th January 2009, 14:25	#1
NikTheGeek Gets stuck in 2002 Range Rover P38 Join Date: Dec 2008 Location: Wigan Posts: 593 Thanks: 0 Thanked 0 Times in 0 Posts	FBH remote operation circuit I know this has been discussed to death, so apologies, but I can't find the answer I'm looking for. I've just purchased a 12v remote switch with key fob from Maplin. I know I need to short pin 3 to make the FBH fire up as I've tested it by manually shorting pin 3 to gnd. But: my remote switch can be set to momentary or latching switching. So a single press can turn on and another press turns off; or it turns on for the duration of the press and as soon as you stop pressing, turns off. Which option do I need? Once its turned on, does it stay on until you disconnect pin 3? In which case latching. Or is it timed? If I use latching, will turning the engine on for a journey, then stopping override it and switch it off? If latching, I'll have to rig up some sort of indicator too so I don't accidentally leave it on and flatten my battery... tnx for any advice or suggestions (other than spending loads on a proper Webasto one!) Nick

30th January 2009, 14:37	#2
CDTi This is my second home No longer in the MGR club Join Date: Nov 2006 Location: Tipperary Posts: 3,933 Thanks: 35 Thanked 51 Times in 35 Posts	IIRC, the FBH only stays powered up for as along as pin 3 is grounded - try it yourself to be certain, or someone else will clarify it on here. You could rig up a timer for, say, 10/15 minutes so the FBH will not stay on for too long. It will cut out in any event when a certain temp is reached (68 degrees?). __________________ 'Tis better to be silent and be thought a fool, than to speak and remove all doubt.

30th January 2009, 16:36	#4
-Joe Avid contributor Rover 75 Classic SE 1.8T Join Date: Dec 2008 Location: wink Posts: 135 Thanks: 0 Thanked 20 Times in 15 Posts	timer i have a meastro heated rear window timer (£7 from scrapyard). It should be just the ticket for fbh timing... If only I had an explanation of it's pin outs. Need an old haynes manual for a later model meastro used to have one..... can't find it.

30th January 2009, 16:49	#6
CDTi This is my second home No longer in the MGR club Join Date: Nov 2006 Location: Tipperary Posts: 3,933 Thanks: 35 Thanked 51 Times in 35 Posts	I thought about using a spare heated seat switch as an FBH timer. There is a 10 minute timer built into each switch. I think it switches the ground. You could easily add one to your dash, assuming that you haven't got all 5 slots already filled :lol:. __________________ 'Tis better to be silent and be thought a fool, than to speak and remove all doubt.

30th January 2009, 17:31	#7
FROGGY I really should get out more....... MG ZT CDTI Join Date: Sep 2007 Location: 17500 REAUX, CHARENTE-MARITIME Posts: 2,749 Thanks: 2 Thanked 133 Times in 90 Posts	Nick Why not use the feed to the FBH from the Remote module to switch an LED as well? That way, even if the FBH is quiet, the LED will still be on. Mick __________________ http://i200.photobucket.com/albums/a...ps628d4119.jpg IN THE BLACK NOW

30th January 2009, 14:43	#3
NikTheGeek Gets stuck in 2002 Range Rover P38 Join Date: Dec 2008 Location: Wigan Posts: 593 Thanks: 0 Thanked 0 Times in 0 Posts	Ah, ok, cheers. I'll try it. I could always rig up an LED near the wiper mounting so that I can see its on, but I didn't know it would cut out anyway. ISTR reading someone ran their battery flat leaving one on. I'll try it anyway. Maplin do a timer for £7.99 that I could get.... Nick

30th January 2009, 16:42	#5
NikTheGeek Gets stuck in 2002 Range Rover P38 Join Date: Dec 2008 Location: Wigan Posts: 593 Thanks: 0 Thanked 0 Times in 0 Posts	Works a treat. The remote module sits inside the battery compartment with a single small wire going to pin 3 of the FBH connector. I used an ATX power connector (from a pc) and pulled one of the female pins out and shoved it down the hole where pin 3 is. Sort of worked, a bit hit and miss, but with a bit of solder to make the hole narrower it fits electrically well now. The key fob has a great range. Works from inside the house If I click it, the FBH fires in to life and runs. If I click it off, it goes in to its shut-down cycle. But therein lies the problem, you don't know if you've pressed it off or not unless you hang around to check it goes off. So I still need some sort of visual indication. It might be easier to find the pin-outs of the 6 pin plug and find one that has a 12v feed when the unit is powered up and then tap a light or led in to it. Otherwise, its playing with a timer... tnx all for your help in various threads over the last month or so! Nick