FBH - Activation Via Text Messaging by DaveyC

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If you have ever wanted to turn your FBH (Fuel burning heater.) on/off via texts, here is how I achieved this.

This is the module which you can get from here: http://www.lewisrendal.co.uk and the full setup instructions are on there and are very easy to follow (take your time and READ them).

The module looks like this:


The units now come with the appropriate sim card, so there are no issues on compatibility.

You will see in the picture that there are actually 2 relays, so you have a spare to activate something else on the car such as the ATC (Automatic Temperature Control) unit to turn the blower on in addition the the FBH.

The connections really are very simple. You only need 3.

1. Permanent live

2. Earth

3. Connection to pin 3 on the FBH

Before I installed the unit in the car, I wired it up to a 12v supply, so that I could program it to respond to my mobile and check the operations before going any further.

Here is a pic of my bench setup:


The positive wire goes to the connection marked "+V" on the board. The connectors simply screw down onto about 3mm of the bare wire.

The negative then goes to the connector marked "0v"

You are now ready to start the setup:

1 Power up the GSM unit by connection the ires to a 12v DC power supply

2 Wait until Red Network Led flashes once every three seconds

3 Place Jumper in position next to black chip

Here is a pic to help with 3, but the aerial is slightly obscuring the jumper.


4 Call the unit using your mobile phone

6 Save LED (Light Emitting Diode) will be on permanent (yellow LED in middle of the board)

7 Replace the jumper into its original position (see pic above)

8 Now send a text to the unit S1 You can save five numbers in the unit. S2, S3, S4, S5 need to be text for other numbers. For each additional phone number you wants to save you will need to repeat steps 2 to 8.

9 When done Save LED will flash quickly several times indicating the save has been successful.

You are now ready to text the unit to test the functions.

The relays by default only pulse on for a second or so and to run your FBH you will need to send a command to tell it to stay on when you text it.

Text the unit with the following: SO1

This will tell the unit to make relay 1 turn on and stay on when commanded.

To tell it to do this for relay 2 text: SO2

The unit will not make any noise and no lights will flash for this, so don't worry.

To turn on relay 1 text: R1on

To turn off relay 1 text: R1off

To turn on relay 2 text: R1on

To turn off relay 2 text: R1off

You dont need to have anything connected to the relay connections to test the unit, as the relays have a red LED, which lights when its on.

Below is my crude test at lighting a bulb when calling the unit from my phone but only relay 1 reacts to incoming calls. Click the pic to play the video.


You can set each relay back to its default pulsed state by sending either Pu1 or Pu2 in a text.

It you add credit to the SIM, you can have the unit text you to confirm ations and you can even check signal strength.

So, if you have credit, here are the commands.

To turn on response texts: Ron

To check signal strength text: Csq

The response to the Csq text will send back a number value. The higher to number, the stronger the signal.

Any number between 10 – 20 is a good reception area
Any Number above 20 is an excellent reception area
Any number below 10 will result in a possible loss of signal

This is helpful when trying the unit in your car, as placement can affect the reception on the unit.

An adjustable timer is available for relay 1. This has to be in the pulsed mode, so text Pu1 to the unit first.

Text "T005" this will pulse relay 1 on for 5 seconds

You can specify up to 999 seconds eg T999 (this gives a time of 16 minutes 39 seconds). T600 gives 10 minutes.

Text the unit to turn relay 1 on for the time you specified. I set it for 15 seconds for a test (T015) then turned it on (R1on). You will see the LED for relay 1 turn on and stay on for 15 seconds and then turn off. If you have response texts on you will get a text when the unit turns off "Relay 1 Pulsed on"

If you want longer time Text "MT" and this will change the time from Seconds to Minutes. To change back Text "ST"

Both "MT" and "ST" will reply (if you have credit on Sim) either "Time delay changed to minutes" or "Time delay changed to seconds"

I mounted my unit in the arm rest cubby. This suited me, as its easy to get a the unit, should you need to get at the sim and its dry and clean.


I ran a wire from pin 3 on the FBH and into the cabin via a rubber gromet in the plenum (driver's side). I then took it through the centre console and under the cubby.

I drilled a hole in the bottom of the cubby and fed the GBH wire in. I took my live and negative feeds from my power socket (need to be a permanent live).

The FBH wires went on relay 1 as shown in the pic below:


1 wire is the FBH wire to pin 3 and the other is Earth. It does not matter which way round these are as the relay simply completes the circuit, contacting the FBH wire to earth, which starts the unit up.

I decided to fit a switch to turn the unit its self on/off for my own peace of mind.

As you will see I made a false bottom out of some very thin plywood and covered it to make it look more OEM and fitted my Aux socket to it, so I did not loose the functionality.


All done and now you can text your car from wherever you are to fire up your FBH and don't need to worry about remembering to turn it off (as long as you set the timer up!).

Hope this has been of some use...........

Dave :-)

Posted 13 Nov 2013, 08:04 #1 

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Dave excellent post i think you may have a few members asking for this at the nanos Arctic

Posted 20 Nov 2013, 01:54 #2 

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Cheers Steve. My unit is back with the guy for an upgrade, as mine was an early one and only had the ability to specify time on in seconds. Should be minutes like his new units when I get it back. Hope its soon as its flippin freezing here this morning.

His ebay auctions are here: http://www.ebay.co.uk/sch/lewisrendal/m ... 1438.l2654

Worth keeping an eye on what he has for sale, as some weeks he puts up 2 or 3 and I bagged mine for £30!! Its a cheap way of doing this. The chinese ones are twice the size and double the price........

I don't mind fitting these at Nano's if members are struggling. There are a couple on the OC that have bought them already (Duotone for one but he has not posted his findings as yet).

Dave :-)

Posted 20 Nov 2013, 08:14 #3