A Viking’s Journey into GD MK4 land

A Viking’s Journey into GD MK4 land This page is to catalogue my joys and exploits in building a Gardner Douglas MK4

‘Ere wago ‘ere wagoJust a quick update on the power and illumination circuit for the Speedhut Custom Gauges. As mentione...
24/08/2026

‘Ere wago ‘ere wago

Just a quick update on the power and illumination circuit for the Speedhut Custom Gauges. As mentioned elsewhere, Speedhut don’t make a series harness for the LED gauges so I’ve had to come up with a solution of my own.

I’ve used Wago connectors on my model railways and around the house for years and my local sparky uses them all the time, so I’m confident they are good for the job at hand. Part number 2773-408.

Each one takes up to eight wires all connected together just like a compact bus bar. More than capable of handling the load from the Speedhut dimmer controller.

The connectors need a rigid wire input, so I used a good quality ferrule on each wire and they locked nice and firmly into the connector block. Each block will then be bonded onto the back of the dash.

Works a treat and hopefully an idea than might be of some use to others.

23/08/2026

Surviving First Contact?

Well I know it’s not starting an engine for the first time or anything as exciting as that, but having had a little bit of build fatigue over the last month or so, I was very lucky that SWMBO gave me a couple of days this weekend to go play with Hela.

I decided that I should really use the time to get on with the last of the big wiring jobs, so wire st*****rs in hand I set forth…

First job was to finish wiring up all the dash switches, which have all been done on the main dash including the dual intensity lighting circuits. The lighting for the lower dash switches (courtesy lights and heated seats) needs to be still added. All the extra circuits work (front heated screen, auxiliary cooling fans, courtesy lights in both footwells, front fog lights (more on those and the DRL set up at a later date)). Thanks again to the team at Car Builder Solutions for all their help and patience with me whilst I worked out what I needed.

Second up was those beautiful gauges from
Speedhut Custom Gauges in the US. So easy to fit. Nice and shallow too. My only trouble was working out how to wire them up to the Speedhut dimmer module. For the non-LED gauges they make, Speedhut can supply a wiring harness that links them all in series. Sadly they don’t make a similar harness for the LED gauges and they all have a custom plug on the end of the OEM harnesses. Linking all the wires (three to each gauge) could be achieved using a good old fashioned bus bar but they are very bulky for behind the dash.

Thanks to the InterWeb thingy I managed to find a nice elegant solution - an 8-way Wago connector. It is designed to cope with vibrating environments and typically is used with a single core wire - the gauge harness is of course multi-strand. Solution - a trip to Valhalla (my garden workshop - can you see a theme here?) and grabbing some ferrules. Easy peasy lemon squeezy. Wires routed, stripped, ferrules fitted and pushed into the Wago connector. Each connector will then be bonded to the back of the dash and the wires tidied up as normal.

So, most things have now been done on the dash itself and all the wiring completed. Thanks to those on the GD forum for their support with getting over little the slump - two days of cracking on seems to have been what the doctor ordered.

I still have some wiring left to do - finish off all the DRL module wiring behind the dash, make a couple of harness bits at the front for the fog lights, sort out the EPAs and ECU feeds (wiring done - just need to add the end connectors) and put the wiring in for the radio and screen, but I’m a lot happier now.

And now the reason for the title - I closed the evening off by firing up the dash and checking all the circuits. It was so very satisfying to see the gauges fire up, do their dance and settle back ready for the various inputs in due course. What a great start up routine that will be! So I thought a little video would be in order showing that sequence - hope you like it.

10/07/2026

A nice little home brew DPDT car instrument switching module. Boards courtesy of a Chinese manufacturer to my design, rest by me.

Shedding a little light on mattersWell my little circuit boards arrived from China today along with some of the smallest...
10/07/2026

Shedding a little light on matters

Well my little circuit boards arrived from China today along with some of the smallest electronic components I have ever seen! Think half a grain of rice in terms of size. A bunch on 1N4007 diodes and some 1.5k ohm resistors.

Like the little gnome I am I shuffled off to my workshop and dug out my soldering iron, flux and a bleeding great magnifying glass with a light on it (thank you GloForce for your units which initially I bought for playing model railways!).

Fly leads attached and components mounted, it was testing time. It worked - she’s alive (cue Weird Science music). The back lights come on dimly with the sidelights and then strengthen when the switch is pressed. It’s deliberately subtle - I could ramp up the resistor to get a more dimly lit “sidelight” mode but I am happy with what I have.

Tidied the whole lot up with some glue-lined shrink tube and I think they make a nice tidy little unit. Well worth the time and the eyestrain IMHO.

See what you think?

Resting on my laurels?You may remember that I have been toying with the idea of an armrest / centre console for the back...
08/07/2026

Resting on my laurels?

You may remember that I have been toying with the idea of an armrest / centre console for the back of the transmission tunnel to (a) house a mobile phone charging pad and (b) provide a tiny bit of storage for a few bits and bobs.

Well, in one of those idle doomscrolling moments last night I came across a Subaru Impreza arm rest lid on Fleabay. It’s about the right size and has the hinge and latch already attached. I am sure I can modify / butcher the pad etc to make it fit the dimensions of the transmission tunnel and can use my O level woodworking skills to build the lower half of a box from mdf and fibreglass. I can add a metal latch plate at the front to work with the lid catch and a separate pad at the rear to cover the hinge with push down clips to lock it in place. It will then be up to Robin and team at Intatrim to make it look nice or tell me I’m a complete idiot! Only time will tell…

Anyway, here’s a picture of the lid and I will update everyone once I’ve finished with the router / saw and the fibreglass and filler.

And even more electric trickery!Not much to update on except I am still finishing up the joy of the wiring. Having prove...
05/07/2026

And even more electric trickery!

Not much to update on except I am still finishing up the joy of the wiring. Having proven all the circuits with the help of Captains Bodge and Fixit, it has been steady but slow progress in converting all the Heath Robinson connections to proper reliable links and putting the finishing touches to the dash loom.

Where possible I have chosen to pick up feeds from the GD loom, and then extended them with matching wires to terminate in the 2.8mm connectors on the back of the Car Builder Solutions switches.

All terminals have been insulated using adhesive lined shrink tube and each leg has been wrapped in automotive quality braided sleeping. The ends of the braid have then been finished with more shrink tube and each “leg” labelled with its purpose using shrink tube printed labels.

For switches, I have also added a pin number to each wire (B1, B2 etc) so that when the dash comes out for trimming we know where each and every wire goes back to. Hopefully the switches will only need their illumination feeds removing since the DPDT switch block is independent to the switch but it’s better to be safe than sound.

Talking of switch illumination, watch this space for a little bit of fun / total overkill. Having worked out (with some advice on the use of diodes) the circuit for making the switch lighting change intensity depending on whether they are open or closed, I wanted to try something a little more permanent looking than a bunch of electronic components soldered together and held together with sticky backed plastic (those who know, know eh?). I found a natty little piece of free software that allowed me to design a tiny little circuit board that takes surface mount components and am currently awaiting a shipment from China of twenty little boards that cost very little. Much easier than DIY with veroboard and the like. I will put up a separate post when they are done and dusted.

So the dash loom is nearly done. I’ve also mounted the screen and wiring for the stereo screen and will again post a separate piece on that. In addition, I spent two or three nights rewiring the heated seat circuits to fit the car properly (will do a post on that too) - it’s really clever (to this Luddite anyway) how they get them to have two heat settings using parallel or series wiring of the seat pads. Back to ‘O’ level Physics to remember all those calculations and wiring diagrams. The pain of it all!

Getting there but at the moment it’s all in twenty to thirty minute blocks in the evening when I’ve finished work and my domestic duties, so it’s frustratingly slow progress. Hey ho - Rome wasn’t built in a day as they say.

Here’s a picture of the dash loom as it currently stands with all my OCD work to date.

Carry On Screening anyone?Just a little update after a busy weekend and an awesome trip to Glyndebourne last night to se...
14/06/2026

Carry On Screening anyone?

Just a little update after a busy weekend and an awesome trip to Glyndebourne last night to see Tosca.

The real dash is now test fitted and all is well. Some trimming needed around the scuttle edge to allow the gauges and tell tales to clear, but not much else worrying me at the moment.

Took the time to test fitted the screen for the stereo - a lovely Pioneer unit with remote screen and a head unit which goes in the boot. The screen fits nice and snug up against the bottom of the long dash and leaves just enough room at each side I reckon to fit the heated seat switches and the courtesy light manual switch. I will probably put them on the curve I’ve marked with the chinagraph pencil. Lower row of gauges still clearly visible and I can reach all the other switches from the driver’s seat.

Next step is to lay down a sheet of 9mm marine ply on top of the tunnel to allow me to (a) route the cable from the head unit to the boot, (b) speaker cables perhaps coming back the other way and (c) maybe even a pop out cup holder in the passenger footwell. It also allows me to screw down the screen bracket without breaking through the transmission tunnel. That said there will be a rather large hole through it for the gear lever so perhaps I’m overthinking it for a few rivnuts?

Holy Dashboard Batman!Well the time had come to put my big boy pants back on and cut the holes in my GD long dashboard. ...
12/06/2026

Holy Dashboard Batman!

Well the time had come to put my big boy pants back on and cut the holes in my GD long dashboard. The plywood one had done its job and helped me get everything sorted layout wise, but now I needed to crack on with finalising the dashboard wiring and getting all the other wiring and heater ducting finalised behind and under the dash.

Cue lots of work with compasses and checking the various moulding pips on the GD dash to make sure it all lined up properly. Then it was out with the rather large (100mm and 52mm) hole saws for the gauges and then the tapered drill bit for all the switches and warning lights. All polished off with my Dremel.

I so hate fibreglass cutting and trimming - itches for days afterwards even with gloves and the shop vac running full blast.

Happy times until I realised that I had forgotten that the heater rotary switch is a smaller diameter than the Car Builder Solutions billet switches. Fudge. Out with the Isopon P40 with reinforcing fibres and some tape. It says it works for large holes so I hope it does! That can cure overnight and I will re-drill the 20mm hole for the heater switch tomorrow.

The glove box is also now bonded to the dash and I’ve started the filling around the front rim to get that all nice and level. I I’ll leave it to Robin and the team at Intatrim to tell me if I’ve gone too far.

For the glove box door I’m using the piece I cut out of the dash. Hinges will be rather special thanks to the rather wonderful and very kind Nigel Cooper who let me have a pair of his very natty and beautifully designed hinges. More of those in another post. I’ve got a tidy little black lock for the glove box door which I will also fit at a later date.

I’ve fitted cage nuts to the scuttle edge so that I can attach the dash to the body. For the IVA I will use pan head M6 screws but they will be replaced with some nice M6 thumbscrews in due course. Should make it relatively easy to remove the dash in future if I ever need to rather than ferreting around trying to undo nuts and such like.

My final task this weekend will be to refit the dash and make sure I’ve slough clearance on the scuttle edge around the gauges and the indicator telltales. More itching beckons as the Dremel comes back out👿

I’ve ordered two APEM heated seat switches from Demon Tweaks (CBS don’t stock them ☹️) so once they come in I can check the layout on the bottom part of the dash to see if I can fit both a heated seat switch and the courtesy light override switch in the not of the dash below the support bar whilst not having them hidden / inaccessible behind the floating screen for the stereo that I’ve bought from Pioneer.

One of these days I will finally finish the interior wiring and I can move onto the chassis build. Sadly that’s the name of the game when building a car in half hour / hour increments and having a family life.

Resting on my laurels?Do you ever get one of those ideas for your GD Mk4 that just ni**le at you for months on end? Like...
11/06/2026

Resting on my laurels?

Do you ever get one of those ideas for your GD Mk4 that just ni**le at you for months on end? Like an itch that you can’t quite scratch?

Mine was a little nerdy tbh - how should I accommodate my iThing into the car? I’ve got Apple CarPlay through the Pioneer head unit I’m fitting, but I don’t really want to have my phone stuck on a stalk somewhere or rattling round the glove box tethered to a cable that’s going to get in the way all the time.

My daily driver has wireless car play and a charging pad. Could I put a charging pad cleanly into the car? I would like the phone to be hidden / out of the weather (they don’t like direct sun!). Where to put it? The glove box is an obvious choice but then I couldn’t put anything else in there. Mmm. Mind churning.

Head explodes. What about an arm rest? One that opens like a clamshell. With a little bit of additional storage and a charging pad. I reckon there is about 14” / 35cm from the rear bulkhead where I could put an arm rest about 2” / 4cm high. Nicely rounded and padded. Very comfy. Won’t get in the way of the gear lever. Wires can all be hidden nicely.

Time for a trip to Mr CoPilot. Blah blah and lots of design talk later, something half decent emerged. Complicated. Can it be 3D printed and then trimmed by the very nice team at Intatrim? The latch mechanism and hinges can all be sourced online. Definitely a starter for ten - and do remember I’m not building a classic Cobra replicas - I’m building a Restomod concept so please don’t shoot it down in flames.

So here are the renders and design plans. Now I just need to get the thing designed in CAD in a practical way. Time to learn how to use CAD!!

What a fantastic job by Martin - he really knows his game and continues to turn out amazing work on Gardner Douglas cars...
01/06/2026

What a fantastic job by Martin - he really knows his game and continues to turn out amazing work on Gardner Douglas cars (plus a few other lesser marques as well 😉)

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