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Sunday 8 July 2018

Fitting Defender central door locking

I have been working up to fitted the central door locking in Fender.
I am using a kit by Hawk and the immobiliser from a Discovery 1. That immobiliser looks, works and connects, the same as the Defender one but also includes the relay to operate the central locking.

I have now fitted the door solenoids which follows on from my earlier post about swapping the immobiliser for one that support central locking.

Prior to starting I had read a few articles on the Internet about this job and a friend had given me the measurements from his install. I've used that information to come up with a plan:
  • The solenoid is away from the rear edge of the door so the door card will fit without any cutting.
  • The solenoid in its extended position is under the interior door frame to ensure it does not foul on that when operating.
  • The brackets are bent in a step to avoid it catching on the window as it opens.
Conversely, I've also ignored one of the tips about where to run the cables.

My preference is to run the cables the same way as Land Rover do on the newer TD5 Defenders. That is through the 'A' pillar and in to the engine bay.

I started with the rubber cable grommet (part number YQQ000070) that runs from the door to the 'A' pillar. The cables run through and are protected by this. I was unable to find exact measurements for the position of the rubber conduit but I made a best guess from some photographs.

The door card limits the possible positions for a bracket to secure the door end of the conduit to.  There is a raised area on the inside of the door card that supports one of the plastic clips that holds the door card secure.  The new bracket needs to be placed just above that.

The lower edge of that is 160mm above the bottom edge of the door's steel frame.

I believe that on the TD5 the bracket is welded on to the inside face of the steel frame however the window runners on our Defender were too close to the frame to secure anything on the inside face of it. The solution for that was I used a right angle shape and fixed it to the top of the frame with self taping screws.

I drilled 2.5mm holes in the frame to fit 4mm self tapping screws. The holes in the bracket were 4mm.

The bracket is made from a short length of stainless steel capping usually used to protect stable doors. Any thin steel would have done.

They are 45mm long, 20mm deep on the face fixed to the frame and 25mm tall away from the frame. The slot is 15mm wide and 30mm tall at the apex.

For the other end of the rubber conduit, I used, drills, a rotary tool and files to cut the hole through the trim and the 'A' pillar.

This hole is about 20mm under the door switch. 20mm wide by 27mm tall in the centre of the pillar.

The door card needed to be cut for the grommet to pass through.

I used a 10mm drill to form the round end and then simple cuts to form the slot.

The next bit was fitting the solenoid. I spent a long time working out where the door card curved and then widened out. For the passenger door, I positioned the flat steel bar centred at 160mm from the edge of the steel door frame. When I assembled it all, this fitted but was tight up against the curve of the inside of the door card. For the drivers door I centred the bar at 165mm from the edge of the door to give a little bit more clearance.

I drilled some holes in the inside metal panels of the door. I used an M5x10mm bolt for the top of the support bar and a 4mm self tapping screw at the bottom.

IMPORTANT: make sure the window is fully wound up before drilling any holes to avoid any chance of breaking the glass with the end of the drill.

The kit I had came with 4 flat bars with holes in to support the solenoids. That is one bar for each solenoid. I used two bars for the one solenoid, so if you have 4 or 5 doors and not the two I have, you are going to need to get some extra bars if you use my suggested mounting position.

The two flat bars overlap in the middle and the screws through the solenoid holds the bars together.

The lower bar is bent out by 20mm at a height of 75mm above the bottom of the door or, in my case, 70mm from the end of the flat bar. This gives plenty of clearance for the window and roughly follows the profile of the inside of the door card.

On the driver's door I had to force the bracket out slightly with an extra bolt, just to keep the solenoid in the right place.

While mentioning the driver's door. It was so rusty that I had to fill it and use a wall plug to secure the bottom screw!

Moving on to the connecting rod from the solenoid to the latch mechanism. The way the kit indicates connecting this is by bolting on to the exiting lock rod however the latch has a very convenient 6mm hole which I decided to use.

I purchased suitable rod linkage retainers for the purpose. This will make the finished job look much more like something that would come out of the factory and hopefully more reliable than the bolt on bracket.

The distance from the end of the solenoid plunger is slightly longer than the length of the rods supplied in the kit. They would reach in a straight line but that would not work very well. Either end of the rod should be in line with the direction of travel. I could have joined the rods but, again, that does not look very tidy. I purchased some 600mm long 3mm diameter stainless steel rod. As it turns out I could have purchased 300mm lengths.

I bent the rod with two, approximately 45deg bends and two parallel lengths at either end. The advantage of this is that the rods can be fine tuned by adjusting the bends if necessary, which it was not.

To make the tight bend at the plunger end of the rod I clamped it between two steel bars. As it was close to the vice jaws, I used two hammers to bend it over. The small hammer is held against the rod and the larger hammer is hit against the smaller to get accurate control of the impacts.

Using the rod retainer, it was very easy and quick to fit the rod in to the door. At this point I rigged up a long pair of electrical wires to test the operation. I was pleased it worked well and the rod did not foul on anything.

Now for the bit many people avoid. Threading the cable through the 'A' pillar.

With the correct tools I found this a fairly easy job. From the engine bay I felt for the wires at the very top of the wing, and followed them to feel the grommet in to the pillar.

I used a nylon cable threading line. I would guess a length of strong strimmer line would also do the job. I pushed the line through the grommet, fairly easily, and continued down the pillar. It was not as far as I expected. With the window open I could adjust the line and feel the end of it inside the pillar from the car interior side. It was a bit tricky to hook the end out through the hole but only took a minute.

That done, I attached the wires, without connectors, to the line and pulled them through. I was using my own wire, colour coded to match the Hawk kit. The wires supplied with the kit were not long enough to run the route I had chosen.

I used 1mm2 16Amp thinwall wire which is slightly larger than that supplied with the kit.

With the wire run and cut to length I crimped on the ends. I don't normally like using bullet connectors but I saw no advantage adding unnecessary joints or in changing the ends from the kit.

I like my cable runs to be tidy and look factory installed, where possible. I used spiral wrap in the engine bay. A bit time consuming but the result is one of the better solutions to protect the wires. Cable tied along the back of the engine bay.

There was no need for any protection for the wires inside the doors. I just used a few cable ties and tape to hold them in place.

On the drivers door, there are additional wires. One is an earth. It was not strictly necessary but I decided to earth the door using the bolt I added for the top of the bracket. From that bolt I ran another wire to the solenoid.

I connected the other end to the earth bolt under the bonnet on the bulkhead.

When I got to this stage on each door, I checked it all worked and then put the door back together.

With the door card in place, the passenger door worked fine but when I did the drivers door the lock would stick causing the solenoids to repeatedly try to lock and unlock.

It took a while to identify the problems. Firstly I found the lock button runner was broken so the escutcheon would catch on the button.

Once I had replaced those bits of plastic, it still stuck some of the time.

My best guess for this was that the door latch was stiffer than the passenger side. I oiled and greased that and worked it a little. That appears to have fixed that.

Lastly, I had cabled tied the 4 wires of the drivers door solenoid, on to the outside of the support bracket. I didn't realise the card was that close and it pushed the solenoid under the glass, so the window clipped it.

I had to reposition the wires so that they run on the inside of the bracket and force the bracket away from the window.

After having put the door card on for the second time, the drivers door worked.


Related articles:

External links:


Updated: 8 July 2018
The drivers door proved to be more difficult than the passenger door. These notes were updated to reflect lessons learned.


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