Digital Instrument Cluster
A How-To Guide For The DIYer


     I had been attempting to work with Nordskog to build a digital instrument cluster for the Probe but the company went under in the typical corporate fashion.  So I went looking to see if I could find a suitable digital cluster which could be reasonably easy to install.  I found several possibilities such as the Ford Tarus, Ford Windstar, Mercury Villager and Buick Riviera.

The Cluster:

     I chose the Mercury Villager cluster from the 1990's because as seen to the right -it is very similar in size and shape.  Also it had the highest reading tachometer out of all the other possibilities.  It will go to 8k RPM which is a good limit for our engines.

     The Villager is a 6-cylinder which makes it a good candidate because the tach will read the correct RPM.  Also -the temperature sensor has the same signal output as our Probe sender does.  So the Tach and temperature are no-brainers.  

The How-To:
Here is the Villager cluster when lit up:

     The Outside Air Temperatrue (OAT) is a nice "gee-wiz" feature but is really un-necessary and the KL cars do not have a fuel flow signal from the ECU to make use of the fuel economy computer function.  So since the displays are individual tubes it is easy to remove the un-needed display to the far left.  This will make room for other more important guages such as oil pressure or O2 wideband, etc.

     Below is the main printed circuit board (PCB) that does all of the calculations and conversions for the displays.  It is not necessary to do any modifications to this board.

     These are tools that you would need to remove the un-needed display.  The blue thing is a solder sucker and works very good to remove the molten solder from in the holes around the pins.  You can also use de-soldering braid to suck up some of the solder.

     Here is the display board with the tube removed.  Notice how I filled the holes with solder after the display tube was removed.  This is to keep the foil tracings connected from one side of the board to the other.  This is a dual sided PCB -meaning that there are traces as seen in this photo below -also on the reverse side but just with a different layout.  This is called very good usage of all available real-estate.  There are too many circuit paths to be able to lay out the entire circuit on only one side of a board so they also use the back side.  If you do not fill the holes after removing the tube then you may be creating an open in a circuit that lights one of the display tubes that you do want.  So fill them well.  Also notice in the photo below how the corner has been rouned off.  This is for a clearance issue.  The last three holes on the left are only used to help hold the tube in place.  They do not have any tracings on either side of the board so it doesn't matter if you cut into them some as I have done.  Just be careful when rounding the corner that you do not remove any tracings near by.  The large green areas are typically grounds and it doesn't hurt any to cut into them some either.

     Here is a VFD type oil pressure gauge and I have cut the casing carefully with a Dremel and removed the display to mount it to the display PCB while mounting the circular PCB shown somewhere remotely with a ribbon cable connecting the two.

     Now it is time to do some plastic welding to join the PGT cluster housing and the Villager one.  I cut both pieces so that I have the forward rim of the PGT cluster and the back shell of the Villager since it has all of the mounts for the PCB's.

     Here is the finished welded shell with the PGT connector coves welded in place to make it so that the stock PGT connectors will still plug into it and keep it totally plug-n-play.   The measurements are for locations for the coves that miss all essential electronic components inside the housing.  If you do not place the coves in these locations then you could end up with some bent over components when you fully assemble the unit.

     Here is how I melted some stubs of plastic to hold in the foil traces from the back side of the PGT cluster for soldering wires to.  I drilled small holes just to the ends of the foil traces where it was cut so that the holes will stabilize the wires.  once you weld on this foil -the plastic in-between WILL MELT!  So after you have them all soldered and the plastic is missing between them all then you need to glue everything in place with silicone glue as shown.  This secures everything nicely and the PGT plugs will now plug right in just as they did with the OEM piece.

     Here is the inside view and the Villager plugs when spliced in.  They will connect right up to the Villager PCB nicely inside the housing.  Click here for the Villager wiring diagram.

     This is a VFD display for speed only and it comes from an eighties model Lincoln.  I plan to make a Head Up Display HUD from this one.  A HUD is where the speed is projected/reflected onto the windshield so that you can see it in front of you without taking your eyes off the road.  Several newer cars are coming out with this option.

     I have been running the display for a while installed within the car.  So far - the test results are fantastic.  It took a bit to get the fuel tank sending unit tweaked for correct readings but after that - it is so linear that it appears to be more accurate than a stock Probe fuel guage.  The shot below was taken using a flash.  The flash goes through the 1/8 inch thick blue Plexiglas filter that I have cut from a sheet and thus shows the display tubes behind the filter.  The Plexiglas must be cut with a rotary drill type cutting tool.  Any sawing type tool will cause the Plexiglas to crack.

     This second photo was taken without a flash to show more closely what the display looks like (without the over-exposure blur of this one).  When you shoot a light source it can often cause the blurring effect.  But at least you can see close to what it looks like here:

     These types of digital clusters can be fit similarly into other cars such as the Mazda MX6 or 626.  I know of a few people who have started a similar conversion for the 626 so when they are done -perhaps we can post photos of those as well.  The numbers up in the top right hand corner are my oil pressure.