F78 Rear Door electronic lock

Submitted by markdg123 on

Forum: 

Hi folks. I have just bought a 2000 F78 TDX-SE wagon with full spec including a switch in centre consul next to hand brake that allows you to lock or unlock the rear tailgate door.

The problem is it does not work. I have stripped the switch down and i do have the correct voltage and it does make and break.

I then stripped down panel on rear door and traced wiring to the unit that operates the door lock ( a solenoid possibly? )

I have a voltage here too when the switch is operated but nothing happens. Im assuming that the solenoid unit is faulty.

Can anyone confirm this or give me some advice on the subject please?

Also will need a replacement if it is faulty so if anyone can point me in the right direction to obtain another i would be very greatful indeed.

Thanks guys. Regards. Mark.

F78 Rear door electronic lock

Submitted by rocky4x4 on

Interesting post Mark,I have had a 93 2.8TDX for 13 years and the electronic switch for the rear door has not been funtional for most of that time.I found out why a couple of weeks after we bought the vehicle, the fuse was blown. The fuse(just above the front n/s footwell) was duly replaced and the switch activated, the fuse promptly blew!I could not find anything amiss with the switch or rear door switch so presume this to be an anomoly of Daihatsu wiring.
The vehicle is fitted with remote control central locking and Daihatsu Alarm which I believe were fitted when the vehicles arrived in the UK by Daihatsu. This locks/unlocks all three doors including the rear so basically I did not investigate the rear door switch circuitry any further as I suspect the post factory modifications by Daihatsu in the UK are not quite fully compatible with the original wiring.
I would be interested if anyone else reports similar.

F78 rear door electronic lock.

Submitted by markdg123 on

Thanks for that info rocky4x4.

Forgot to point out the following things:-

My central locking only locks / unlocks driver and passenger doors and not the rear door.

I do have an alarm on the fourtrak which ive been told was fitted on the vehicle when new. This alarm operates independently from the central locking system therefore i have to lock the vehicle then arm the security system via a fob control.

Perhaps you can inform me if this sounds correct and original?

Going back to the remote switch for rear door, i do however have power at the rear solenoid and i have checked all fuses which all appear fine.

Regards Mark

REPLY

Submitted by STANTHEROCKYMAN on

Hi I have a 93 TDX Independent that we have owned since new My central locking only locks/unlocks the two front doors The back door remains locked We also share the same remote alarm system these were fitted in the UK & are aftermarket I also activate the alarm via the key fob once I,v made quite sure the back door is locked.Your switch problem inside the Fourtrak sounds very much like a seized door mechanism rod something else I have come across regards Paul

Locked

Submitted by assassin on

Rear door solonoids on many Japanese vehicles suffer the same fate, after working on many of these units, i have found the answer.
Solonoids draw a lot of power for a very short time to unlock the door, the main problems come when the door locking mechanism become slightly stiff through age. Solonoids have to work harder to operate the locking mechanism, this additional load means more current is drawn, this extra current will often blow the fuse. This is the first indication that a problem is looming, usually; a strip down and lubriation is sufficient at this stage, this is usually neglected by owners.

Following this, the solonoid tends to develop an internal short circuit, this then stops working all together.
Two types of mechanism are fitted to the Fourtrak, a solonoid based mechanism or an electric motor driven rack and pinion type. On the motor driven type, the motor tends to go, this leaves two options, replace the solonoid or the motor, or replace the unit with a motor driven one from another vehicle, or a supplier.
Replacement motor driven units can be obtained from Maplins for £9.99, this does mean additional work making it fit, but the effort of making the bracket is worthwhile.
Model motors can be used to replace the standard motor, model shops will supply heavy duty versions of these cheaply.