Search This Blog

Monday 4 October 2021

Defender Puma heated seat electrics

We already had the Exmore Trim heated seat elements in the seats in Shelley's car. I wanted to wire them in using the original Land Rover switches.

It was easy to find a set of switches on ebay with the connectors. I'm not keen on them being pre-wired but that's how they came. Land Rover's standard wiring has the heating element controlled directly by the switch. I was unable to find out the current limit of the switches, nor the current draw of the Exmore Trim heating elements. All I know is that they use a 20A fuse for the pair.

It is safe to assumed, that the seats draw less than 10A per seat. I didn't want to take any chances with the Land Rover switches, so I have run them to relays.

The above is the updated circuit diagram with the heated seat switches connected via fuse 33. I also ran cables ready for a Sub-Woofer. The positive feed is shown in the above diagram, connected via fuse 32.

I was able to buy the contact pins that fit the standard Land Rover fuse boards, so I was able to use two of the spare ways in the under dash fusebox, to fit the fuse for the heated seat switch feed and another for the sub-woofer power. Both are switched from, what is called, the Window relay. That relay feeding various things, like electric windows and heated seats, when fitted, plus the windscreen wipers.

It's a bit tricky to access the fusebox because, although it can be unbolted, it does not fit through the opening in the dash. I managed to do what I needed.

I had a bit of luck with the feed for the power to the seats. There is an unused fuse in the under seat fusebox. Fuse 4. I happened to have the right spade connected to add in to the plug in that fusebox to connect to Fuse 4 and that fuse is marked as 20A. Perfect for my needs.

I ran a wire from the under bonnet ground stud to an unused stud under the seat. That probably wasn't necessary but with a definite negative connection to the under seat point, I was confident using that for all the negative connections.

I made up some harnesses and threaded them out in to the engine bay and under the car to the UK drivers side seat box. In that box are the two relays. They are attached to the relay brackets handily provided by Land Rover. From there another cable runs to the UK passenger side seat box.

It's just a job of terminating all the wires and plugging them together.


Thursday 9 September 2021

Hot box

It is often convenient to be able to put tools away while they are still hot. To make this safe, I keep my soldering irons and hot air guns in metal cases but it is necessary to keep the hot ends away from anything else, including their own leads.

Having added a rework station to my collection, I needed a different box. For this, I have used a large army style ammo crate.

I've added divisions inside to separate the hot ends from the other items in the box.

I got carried away. I've sprayed it a gun metal colour...

and stencilled some lettering.


Tuesday 31 August 2021

Home made twisted pair audio cable

I'm not sure if many people would appreciate my reasoning but I decided that I could make a slightly tidier job if I used a twisted pair cable to connect up the sub-woofer in Shelley's car, rather than a long RCA (phono) cable and an adapter.

I could buy twisted pair cable but for a one off job I decided I might as well make my own. To that end, I rigged up a tool out of short lengths of timber and some spring clamps.

I use the spring clamps and timber, rather than the vice, so that the cables do not get crushed. I use the same thing when holding wires to be soldered

I spun one end by hand, doing about 40 full turns per metre of cable length. When I stopped to add more length, I put a bit of tape round, just to keep the cables together. Cable gauge and twists are all guesswork but I'm confident it is better than I need.

It took less than an hour to make over 5m, including cutting the timber and threading the outer sleeve.


Sunday 15 August 2021

Defenders update

A lot has gone on with Shelley's Land Rover Defenders over the last few months. It all started back in May, after someone drove in to Fender and wrote it off. Shortly after, we purchased another Defender and we have been bringing that back to the same configuration as the previous one.

The new one has been named, Thunder Truck. It is 11 years newer than Fender but is still over 11 years old. It has a 2.4 TDCi engine, usually called a Defender Puma after the Ford name for the engine.

Fender had done over 250,000 miles. This one is a mere youngster with less than 100,000 on the clock.

Most of the jobs we are doing to Thunder, are jobs that we had previously done to Fender.

Convert it from a van to a pickup.

Swap over the rack from the remains.

Fit more appropriate wheels and tyres.

Fit a double DIN size stereo and replace the speakers.

There are a couple of new things. One odd thing is a hand made dip stick for the coolant because the tank is too close to the bonnet and not easy to see through. A new feature is a lock box in the back, to free up space in the cab.

The rear rack has a cover.

Another convenience is a glove box which very neatly fits on the passenger side of the dash. It was so obvious, I have no idea why Land Rover did not fit one themselves.

The jobs are getting more time consuming. I've started to thread the cables to eventually fit central door locking.

There are plenty more jobs left on the list.


Sunday 11 July 2021

FreeCAD tips and gotchas

I've been using FreeCAD more often recently and I know enough to create the sorts of models I usually want. From time to time I find something in FreeCAD that is either useful or confusing.

Don't Mix Part Workbench with Part Design

FreeCAD 0.19

I was surprised that the shapes in the Part workbench do not fit in to the same structure as the Part Design workbench. This means that if you try to mix the two, the result does not fit in to the Part Design tree structure. That ends up making further edits very awkward.

It is possible to use them together with the aid of shapebinder but that is a concept I also find very confusing.

As the primitives from Part workbench can also be created in the Part Design workbench, there is no need to make life complicated by trying to mix the two.

Boolean Fuse on Moved Parts Clone

FreeCAD 0.19

I spent ages trying to fuse two parts where one clone had to have its position transformed to be in the right relation to the other.

The gotcha is that the Part Transform function is ignored when doing a Boolean on a clone. It is necessary to manually adjust the position of the clone component item, not the whole part.

Once I knew where to edit, the fuse was fairly easy. That said, you do have to know how the Add Part button works for the Boolean method, its a toggle. Once on you can just click any other object and the bool happens.

Can't Export STL if Boolean is Last

FreeCAD 0.19

If the last action, in Part Design, is to use a boolean, the STL or OBJ file exported will be empty.

I just did a superfluous operation after the boolean and the model exported perfectly!

Showing Only Parts of a Component in TechDraw

FreeCAD 0.19

I have found this somewhat awkward.

Adding parts to the drawing is fairly easy. I hide the parts that I don't want in the drawing, using the spacebar. Orientate the view to what I want, move to the drawing and Insert a View using the button.

There is a catch, whenever the view is updated and the other bodies are made visible, the drawing then reflects that and displays all the bodies that I had previously hidden!

Not what I wanted

What I wanted

To prevent that, I turn off the 'Keep Updated' property for the drawing.

There is also a toggle on the right click menu for the drawing.

That's great BUT sometimes when I reload the file, the drawings are all blank. I assume this is a bug, I have not done enough searching to find out for sure.

My solution to this is to hide the bits of the model that I don't want, again, and then press the refresh button for the drawing.

It's not always perfect but it usually gets me back to close to where I want to be. It does require me to remember what was included in my own drawings, so I export to PDF, frequently.

I hope the above fault is just me doing something wrong but, at the moment, I don't know what that is. The tutorials only show examples of complete components in the TechDraw drawing.

[To Try: Separate the bodies for each view in to separate components, to see if that helps.]

Preview a Page in TechDraw

FreeCAD 0.19

By this, I mean hide all the connection points and view frames.

The button tool tip calls it 'Turn view frames on/off' but it also hides all the other bits that won't show in the exported PDF. I think of it as a 'PDF or Print Preview'.



Very quick and easy to toggle on and off, as required.

Showing Hidden Lines

FreeCAD 0.19

A common thing on drawings to be able to see holes that go through objects. Especially if they don't go all the way through.

It's necessary to turn on Hard Hidden in the view tab of the view group.

Then it's necessary to REFRESH the drawing to see the change.

In this case, it makes the drawing easier to understand.

Notes on other view parameters can be found in the documentation:

Hidden Line Dashes

FreeCAD 0.19

I like my hidden lines to be dashes. This can be changed in Edit-Preferences-TechDraw

Details about each preference, can be found in the documentation: