V1 remote display installed inside a Porsche 993 tachometer

Difficulty level: 6 
(From a scale level of 1-10, 10 being hardest)

There have been number of suggested locations to mount the V1 remote display in a 993, the best recommended location has always been around the tachometer area.  Since at this location the V1 remote display is in the directly line of sight, it is the easiest location to view the warning display without taking your eyes off the road.  Since the velcro way of mounting that comes with the kit is not always the cleanest installation method and leaves wires to be exposed, so I decided to install the V1 remote display into the tachometer itself.  What really gave me the courage to cut open the gauge face was due to the fact that I recently upgraded to a set of aluminum color gauge faces, I figured that worse comes to worse I can always go back to the black gauge faces if I screw up.

Important note:
Since the V1 remote display is curved, there will be "raised" area inside the tachometer face after it is installed.  The location I decided to cut the opening to mount the display by luck cleared the tachometer needle by a very small margin.  You may want to make the opening cut on the gauge face a little further down than the location I have chosen.

Since the remote display will be behind the tachometer glass, the mute button on the remote display is no long reachable.  Since the mute button also function as the mode selector button, I choose to run a separate wire to the mute button contacts from the PCB of the remote display to allow me to use the remote button.  If you decide not to run a separate wire the mute button on the V1 main unit will also functions as well.

I also choose to use two separate RJ11 jacks to extend the connection of the V1 remote display to the outside the tachometer in the rear, please double check the wiring color of the separate jacks using a voltmeter prior to soldering the wire as they may not match the color.  I had to swap my wires because they were opposite on the jack I purchased.

Tachometer removal

To remove the tachometer I first remove the smallest gauges first (clock).  Use a flat screw driver wrapped with a towel and carefully pry the gauge out, once it comes out a little bit you can just pull the rest of the gauge out with your fingers.

Once the clock gauge is out you can easily push out the speedometer from behind.

Same for the tachometer, push it from behind first from the opening created by removing the speedometer.  The tachometer does not come out as easy as the rest of the gauges because it will get stuck between the dash lip and the steering column.  It is difficult to describe the exact method I used to take the tachometer off since it is almost different every time. 

Tachometer disassembly

To access the internal of the tachometer first the bezel ring must be removed.  To remove the bezel ring use a flat screw driver to pry up the bezel ring lip from behind all the way around.   Once the ring is removed you can remove the tachometer needle by turning it counter-clockwise and pulling it out simultaneously.  Remove the two small screws that holds the gauge face to the tachometer base.

V1 remote display disassembly

Remove the two torx screw on the V1 remote display unit.  Remove the PCB from the back of the face by prying open the two plastic tabs.  Remove the mute button by pushing the rubber prongs from behind. 

Note: I didn't have a torx bit as small as the ones used on the V1 remote display unit, so I just used a small flat screw driver.

Gauge face/body cutting and fitting

I used the outline of the V1 remote display unit as an outline and draw opening on the gauge face from behind.  (My picture was done incorrectly) 

When making the actual cut I made the cut couple of millimeters from the actual lines I had lay down.  There is a lip a couple millimeters inside on the V1 remote display face which is several millimeter smaller than the actual display outline.  You may need to make several cuts to make it fit perfect, but it is a better fit if you make the cut smaller first and work your way up from there.  This way it also prevents as little light bleeding through from behind at night.

Remove the gauge internal from the tachometer casing by removing the three screws from the rear

Place the cut opened gauge face on top of the gauge internal and place the two black small gauge screw back in so that the gauge face is aligned correctly to the gauge body.  Use a black marker to outline the clear acrylic plastic as the area that need to be cut.

Remove the two screw that holds the clear acrylic to the tachometer body, once removed I used a diamond cutting disc mounting on my Dremel tool to make the cut along the back marker outlined.  The diamond blade melts the plastic as it cut through the acrylic.  Once the hole is cut you will need to use a file to smooth out the surface and also make some minor fit adjustments.  Mount the gauge face on to the clear acrylic plate and to make sure everything fits properly.  As a reference if everything was properly cut the V1 remote display will fit nice and snug even without any glue. 


Now you can clear out the area under the clear acrylic, there are only two plastic post that needs to be cut out from under there in order for the V1 remote display to fit.  On the left side post it needs to be filed down a little than the right side so that the RJ11 connector on the V1 remote display will fit properly.

Wiring connection

To wiring up the mute button remove the rubber mute button from the PCB, and run two wires through the existing two via hole on the PCB and solder the connection from the button side of the PCB.  Before I install the rubber mute button back I had to make two little "V" cuts on the rubber mute button so it fits flush with the extra soldering.  Clip the PCB back into the V1 remote display face.

Make a small hole on the back of the tachometer casing, it has to be large enough so that all the wires can fit through once the tachometer is assembled. 

Mount the clear acrylic plastic back on to the tachometer internal and tighten it back down with the two screws.  Mount the gauge face plate and tighten the two screws.  Place the V1 remote display into the cut out hole of the gauge face.  Hot glue the V1 remote display to the clear acrylic plastic from behind. 

Cut one end of a 4 wire RJ11 cord but make sure the cut is long enough so that the wires can reach from the RJ11 jack of the V1 remote display unit to the back of the tachometer casing where there additional remote RJ11 jack will be installed.  Plug the RJ11 into the back of the V1 remote display unit and run the RJ11 cord along side the tach towards the 3000 rpm area where you find a factory hole opening on the tachometer PCB, run the stripped RJ11 cord along with the two mute button wire through that hole.  Place the tachometer unit back into the tachometer casing and run the wire out through the hole you drilled earlier for wire opening on the tachometer casing.

The extended dual RJ11 that I used for the external RJ11 connection is a common dual RJ11 that usually comes with the DSS satellite installation package.  I made modification to the dual jack by cutting off the male plug and made two holes on the back side for the wire to enter.

I used heat shrink tubes to clean up the wires when the soldering was complete, if you do decide to use heat shrink tubes now it is the time to slide the heat shrink tubes down to at least half way of the length of the wire.  And shrink it down with a heat gun and then cut an equal length heat shrink tube and slide it over the area where you just shrunk.  Make the wire soldering connections at the dual RJ11 jacks and then insulate the connections.  Close the cover of the dual RJ11 jack to hide all the soldered connections and then slide the extra half of the heat shrink tube over the exposed wires all the way to the dual RJ11 jacks and heat shrink it down.  When it is done, it looks like part of the factory wiring connection, I also labeled the RJ11 jacks so I know which connection is used for which.  For the remote mute button since I knew ahead of time that I will be using a two wire RJ11 cord so I know that only the two center contacts on one of the jacks of the dual RJ11 jacks will be used.  Please double check the connection with a voltmeter to make sure the pin layout are as the same as on the V1 remote display jacks.

For the remote mute button, I just purchased a standard momentary contact button from Radio shack and soldered two wires from the other end of a two wire RJ11 jack where I cut the jack off. 

Prior to installing the rest of the tachometer back together now it would be a good time to take the tachometer to the car to make sure everything works.

Install the gauge needle back in, the gauge needle rests 250 RPM below the last mark line on the tachometer.  To calibrate the needle you will need to just turn the needle past the stop mark and force it to go the equal amount of distance for the opposite amount you want the needle to rest.  Install the bezel ring back with the glass, roll the edge of the bezel ring with a round end of a soup can or equivalent.  As I have mentioned in the beginning of this DIY, I was lucky that the tachometer needle barely cleared the V1 display unit.

Installing tachometer back into the dash board

I had a very difficult time finding a grommet opening from the inside of the gauge dash to the bottom of the dash board.  Finally I was able to locate a large rubber grommet behind the oil temperature gauge where I can slide both the V1 remote display RJ11 wire and the remote mute button wire.  I tied them along side of the factory tachometer plug.   I was unable to pull the grommet back up, so I left it as it is. 

I ran the remote mute button wire to the driver's side vent and mounted the button on the grill of the vents.


Here are some finished pictures

Back to DIY menu