How i repaired and modified my FBH system

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dave21478

Active Member
Posts
694
Location
France
2001 TD4.

There have been a few threads about this of late, and since my FBH was non-functional I decided to get busy today.

It didnt work because a while back I removed the wee doser pump from the rear wheel arch as it was leaking. Since winters here are bastid-cold I decided to get busy today and at least get it working as standard for winter time. The pump was quite rusty and one of the metal barbs the hoses push onto had come off (they are a push fit in the pump body with an o-ring to seal). I shoved it back into place and cocooned it with chemical metal. Fixed.

I pulled out fuse 5 in the engine bay box to reset the FBH, but was pretty sure it would not work straight off as the pump only squirts a tiny amount of fuel at a time and the pipe from front to back would be empty. The pumps are not rotary pumps, they are wee solenoid things that jizz a wee bit of fuel with each action of the solenoid. I sliced away a wee bit of insulation on the feed to the pump (white/blue wire iirc - there are only 2, the feed and an earth) and I ran a bit of wire to the battery positive terminal. By touching this wire to the exposed pump feed, the pump would work. I kept tapping the wires together to get the pump squirting and after a few minutes got a faint smell of diesel from the FBH exhaust so the pipe was now primed. I refitted fuse 5 and just needed to get the thing running. You can short out the connections on the temp sensor and the FBH will start when you start the engine ( the temp sensor is behind the front bumper, looking at the front of the car its at the left hand side of the lower mesh grill.) The second way is to supply 12v to the FBH wiring, which will make it work independent of the cars engine running. I undid a few of the screws and pulled up the splash shield in the front wheel arch. The 2 wiring plugs are nearest the wheel. Pin 3 on the larger plug is the one you want - it has a gray and green wire in it. Again, I peeled iff a wee bit of insulation and touched my 12v wire from the battery to it and the thing started. The fan starts up, it whirrs and clunks a bit, smokes a little and then lights up, running with a muffled roaring noise from the wee exhaust. Mine took a couple of attempts to light as it had been unused for a year or so and I also may have flooded it when I primed the fuel pipe. Removing fuse 5 kills power to it and resets it, which I did after each failed ignition cycle.

So that was it repaired - next cold morning, it will start automatically when I start the car, heating the engine up much faster, and allowing the cabin heating to warm up faster too. But why stop there?

I hoiked out the centre console (easy job - follow your Haynes manual) and took a 12v feed from the stereo wiring, which I ran through a 5 amp inline fuse to the blank switch hole to the right of the ashtray on the centre console. I rummaged about until I found a standard sized rocker switch in amongst my junk, which slots into the hole in the console after a wee tickle with a file. Its a double pole single throw switch - ie it will switch on and off two seperate circuits. I connected the 12v feed to the top two terminals on the switch. I ran a single wire from this switch through the bulkhead and down to behind the left headlight, where the FBH wiring comes up into the engine bay. I peeled back the loom wrap and found the gray/green wire and connect my new wire to it so flicking the switch sends 12v through this wire and starts the FBH. The second side of the rocker switch I used to switch on the interior fan motor. If you look down behind the heater controls, you will see wiring going to a yellow relay, which hangs quite near the OBD socket on my car. This relay is to power the fan on speed setting number 4. It was a simple job to run a wire from the other pole of my switch to this relay and connect it to the trigger wire (its red and much thinner than the three other wires to the relay)
So, when I hit the rocker switch the FBH fires up and the heater blower runs at speed 4. Ideal to defrost windows and heat up the cabin while I finish my breakfast. Next step will be to fit a remote control so I dont even have to go outside to start it. Something like this looks ideal...
Single Channel Wireless Remote Control Kit : RF Modules : Maplin Electronics
:D
 
be carefull if it is on 70cms which is 433 mhz band if there are any radio hams near you it may fire it up, now that would not be good in the middle of the night
 
2001 TD4.

There have been a few threads about this of late, and since my FBH was non-functional I decided to get busy today.

It didnt work because a while back I removed the wee doser pump from the rear wheel arch as it was leaking. Since winters here are bastid-cold I decided to get busy today and at least get it working as standard for winter time. The pump was quite rusty and one of the metal barbs the hoses push onto had come off (they are a push fit in the pump body with an o-ring to seal). I shoved it back into place and cocooned it with chemical metal. Fixed.

I pulled out fuse 5 in the engine bay box to reset the FBH, but was pretty sure it would not work straight off as the pump only squirts a tiny amount of fuel at a time and the pipe from front to back would be empty. The pumps are not rotary pumps, they are wee solenoid things that jizz a wee bit of fuel with each action of the solenoid. I sliced away a wee bit of insulation on the feed to the pump (white/blue wire iirc - there are only 2, the feed and an earth) and I ran a bit of wire to the battery positive terminal. By touching this wire to the exposed pump feed, the pump would work. I kept tapping the wires together to get the pump squirting and after a few minutes got a faint smell of diesel from the FBH exhaust so the pipe was now primed. I refitted fuse 5 and just needed to get the thing running. You can short out the connections on the temp sensor and the FBH will start when you start the engine ( the temp sensor is behind the front bumper, looking at the front of the car its at the left hand side of the lower mesh grill.) The second way is to supply 12v to the FBH wiring, which will make it work independent of the cars engine running. I undid a few of the screws and pulled up the splash shield in the front wheel arch. The 2 wiring plugs are nearest the wheel. Pin 3 on the larger plug is the one you want - it has a gray and green wire in it. Again, I peeled iff a wee bit of insulation and touched my 12v wire from the battery to it and the thing started. The fan starts up, it whirrs and clunks a bit, smokes a little and then lights up, running with a muffled roaring noise from the wee exhaust. Mine took a couple of attempts to light as it had been unused for a year or so and I also may have flooded it when I primed the fuel pipe. Removing fuse 5 kills power to it and resets it, which I did after each failed ignition cycle.

So that was it repaired - next cold morning, it will start automatically when I start the car, heating the engine up much faster, and allowing the cabin heating to warm up faster too. But why stop there?

I hoiked out the centre console (easy job - follow your Haynes manual) and took a 12v feed from the stereo wiring, which I ran through a 5 amp inline fuse to the blank switch hole to the right of the ashtray on the centre console. I rummaged about until I found a standard sized rocker switch in amongst my junk, which slots into the hole in the console after a wee tickle with a file. Its a double pole single throw switch - ie it will switch on and off two seperate circuits. I connected the 12v feed to the top two terminals on the switch. I ran a single wire from this switch through the bulkhead and down to behind the left headlight, where the FBH wiring comes up into the engine bay. I peeled back the loom wrap and found the gray/green wire and connect my new wire to it so flicking the switch sends 12v through this wire and starts the FBH. The second side of the rocker switch I used to switch on the interior fan motor. If you look down behind the heater controls, you will see wiring going to a yellow relay, which hangs quite near the OBD socket on my car. This relay is to power the fan on speed setting number 4. It was a simple job to run a wire from the other pole of my switch to this relay and connect it to the trigger wire (its red and much thinner than the three other wires to the relay)
So, when I hit the rocker switch the FBH fires up and the heater blower runs at speed 4. Ideal to defrost windows and heat up the cabin while I finish my breakfast. Next step will be to fit a remote control so I dont even have to go outside to start it. Something like this looks ideal...
Single Channel Wireless Remote Control Kit : RF Modules : Maplin Electronics
:D

Bloody great post, well done and thanks.....;)
 
Pin 4 on the fbh provides power for an interior fan relay after the coolant reaches 30 degrees C.
 
Pin 4 on the fbh provides power for an interior fan relay after the coolant reaches 30 degrees C.

Thats interesting. A wire could be taken from pin 4 directly to the heater relay that I used. Makes little difference for the installation, but would mean the fan would not start until the coolant had warmed slightly.
The advantage of the way I have done it having the fan start immediately is that the air will warm up from cold gradually rather than a sudden burst of warm air, lessening the thermal shock on a frozen windscreen. I doubt if that makes any difference in the real world though!




As for the battery, I am not worried at all.....Realistically this is only going to be running for 5, maybe 10 minutes before I start the car. I haven't the faintest idea what the total current draw of the fbh and the fan on max speed would be, but the battery will be easily capable of supplying this. A 100Ah battery will supply 100 amps for 1 hour or 10 amps for 10 hours or 1 amp for 100 hours.......10 amps is probably not too far off the mark, so running this system for 5 minutes will use less than 1% of the batteries capacity.
 
Good to see people making good use of a great pice of kit if its of any help the wiring is just behind the batttery so you dont have to strip the splash wing off with thows horrible phillips screws :D
 
Hi, is this the incoming cable from the FBH ? If it is, it could be a lot easier to access if the nearside headlight assembly is removed ???

FBH.jpg
 
The cable comes in throw the inner wing on a rubber grommet and goes into a bigger harness its a gray and green wire would make it Essy to take headlight out but you can manage with out bit fiddly but it is possible:)
 
Hi, is this the incoming cable from the FBH ? If it is, it could be a lot easier to access if the nearside headlight assembly is removed ???

FBH.jpg
[Think your spot on not measured resistance but would say that's the gray and green wire the job just get essayer for people:clap2:]
 
To get the headlamp out dont you have to remove front bumper to get at bottom headlamp bolt ? In which case you might as well access the grey/green wire at the temp sensor JMHO
 
Yeah, that's the correct bit of wiring. I cut away the loom tape a few inches above the yellow arrow in your pic and spliced into the gray/green wire there.
Mine doesn't have those two steel pipes though - aircon?
Removing the battery would probably ease access a lot if you can't get at it.
 
Well, there is a typo in my original post - it should be a 15a inline fuse, not a 5a one. Secondly, as I have found today, its not ideal to take the power feed for the switch from the stereo wiring. The stereo wiring is only fused at 10a and about one startup in 10 it would pop the stereo fuse, suggesting that the fbh and fan on max speed draw very close to 10a. Later in the week, I will take the feed from a suitable point at the fuse box rather than the stereo wiring. For now though, I have just upped the stereo fuse to 15a as a temporary bodge :behindsofa:
 
Hi! After reading ur post I decided to get mine workin, I can get the FBh to start but it just sounds like a fan, sounds like its not firing, I pumped what I thought was the fuel pump ( ended up being the washer pump...) where is the pump situated? How do I acess the wires?
 
Washed my freelander today and noticed an exhaust. AND I just bought a Rover 75 this week with a webasto for the coming Swedish winter. Now I want to get my working if there is a heater, I assume exhaust = heater, no exhaust = no heater?
 
I Know I sound a bit blonde, but totally missed it.
anyway, I pulled the No5 fuse (20amp right?) and left 10 mins, temp is about 2C here at the minute, started engine and FBH is not working.
What should I do to get my heater working?
I understand temp sensor thing may be knackered, and to be honest would rather wire a switch in to start it. Can anyone tell me next sequence of events to do?
 
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