transit custom central locking problem

[oldbilly]

I have a Ford transit custom combi trend 310 (2.2 litre) which was converted from new (in 2015/16) to a campervan by Wellhouse leisure. At the time of conversion it was fitted with an Autowatch 695RLC alarm system. This has been synchronised with the remote locking system and is operated by the remote on the ignition key. It does not have a separate remote control unit of its own. After 8 years of ownership I am now experiencing problems with the remote locking/ alarm system. It started with the remote control unit unlocking the doors but not disengaging the alarm system. This meant that whenever I entered the van the alarm would go off. Now the remote will not even lock/unlock the doors, or set the alarm, so I have to get into the van using the key in the drivers door. However, when I do this and start the engine the alarm goes off even though it hasn't been set. If I run the engine for a few minutes or drive a couple of miles it seems to sort itself out. The alarm stops sounding and the remote seems to work again. It has nothing to do with the battery in the key recharging while the engine is running as the spare key also operates the remote, even though it hasn't been in the ignition. Before the drive even the spare key wouldn't work. Its as if there is a rechargeable battery somewhere within the van that can't hold charge any more. After running the engine for a few minutes it gains power and the remote system starts working again but it can't hold the charge for long and the system soon stops working. I am not aware that there is a rechargeable battery anywhere within the remote locking system, other than in the key, and it is clearly not this as both the regular key and the spare key start working after a short trip. Does anyone have any ideas on what is going on here? To add a bit of further information; I have removed the fuse powering the alarm so that I can continue to use the van without the alarm going off. Since then when I get in and out of the van, and the interior light comes on, it is much fainter than normal - this is a bit odd? Also, a couple of years ago, when I got in the van the entertainment console (radio etc) wasn't working. It stayed like this for a few days but suddenly, one day when wiggling the key in the ignition to start the van, it started working again and has been OK since - again very odd. This seems to indicate a loose connection within the ignition switch. It is hard to believe that all of these things are interlinked but, if they are, it suggests an ignition switch problem. Does any of this make sense to anyone and can they offer any suggestions to resolve the problem?

[Altransit]

Most of these electrical gremlins can be attributed to a dead auxilliary battery. If you have two batteries under the drivers seat, then it's one of those two.
In a twin battery Mk7, the aux. is the front battery, but I believe that it's the rear one in the Custom. Getting both batteries drop tested independently would be the ideal thing to do

[oldbilly]

Many thanks for the response. After lots of investigation, further research and testing voltages here and there I was coming to the same conclusion myself: that it was a problem with the auxiliary battery. To check this, I did a voltage check between fuse F39 (7.5A) and earth (it is in the fuse box just above the clutch pedal). According to the wiring diagram in the Haynes manual this provides power directly from the auxiliary battery to the radio receiver that picks up the remote locking signals from the key. You would expect the voltage here to be around 12.5V, but it read 2.8V. Clearly some thing was very wrong. To confirm that it was a problem with the auxiliary battery and not not just some spurious effect I removed the driver's seat to access the two batteries underneath and tested them with a multimeter. Removing the seat is necessary on my campervan conversion but not on standard Transits. With the batteries still connected, the front battery showed about 12.5V and the rear battery 2.8V. After disconnecting them they showed 12.6V and 4.0V respectively. The small increases are what you would expect as there are no longer any systems drawing power from the batteries after disconnection. Starting the engine on the van is no problem so this confirmed two things; that the rear battery is the auxiliary battery on the Transit Custom, and that it had failed big time. Went out and bought a new battery today and fitted it. Everything is now working as it should: the remote locking system, the alarm system and the interior light.

I am posting this update in the hope that it helps anyone experiencing similar problems.

[Altransit]

Thanks for posting back, and confirming the battery locations