Intellitronix Terminal Block

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Major System Category: Electronics
Task: Wire terminal blocks
Parts: Terminal Blocks
Prerequisite Tasks: N/A
Additional Costs: $12
Time Requirement: 3 hours
Date Started: May 19, 2013
Date Completed: May 19, 2013

There are close to 30 wires coming out of the back of the instrument cluster. I had focused exclusively on getting the cluster built that I did not consider what came next. Obviously there is some order to all these wires, I just need to read the instructions that come with the kit to figure where everything goes.

Lots of wires in a bunch of different colors, but they all mean something. Once you understand the meanings, then the  pattern becomes clear and the solution is obvious.

Fortunately for me, this is not Intellitronix first shot at wiring instrument clusters together. There are basically five groups of wires:

1. Ground (black)
2. Power (red)
3. Dimmer circuit (purple)
4. Indicators (various colors)
5. Sending units (various colors)

The solution is something called daisy chaining (at least that's what it was called 30 years ago). I purchased this terminal block from Radio Shack. I then wired each terminal to the next terminal. This means that a single lead can be run to a grounding point for all wires running in the bottom side of this terminal block. Since these are grounds, i wasn't worried about something arcing over.

There are 9 ground wires, 9 power wires (these can segregated into two groups) and 6 dimmer wires. The ground wires are obvious. They need to be ground to the chassis, but ganging 9 ground wires to a single grounding point is unmanageable. Similarly  there are 9 power wires. The six attached to the gauge cluster need to be run to the ignition. There is not enough room on the ignition terminal to run another 6 wires. Finally, the dimmer wires need to be spliced into the head light switch (oops).

This is an insulated terminal block. I used this type of block for everything except the grounds. I daisy chained this block and the one for the dimmer circuit. That way I only had to run 1 lead to each source. This is a much more manageable arrangement.

I purchased three terminal blocks from Radio Shack. For the grounds I could go with an open terminal block. For anything related to positive current, I opted for an insulated terminal block. I discovered I could cut apart the insulated terminal blocks. So I fabricated 2 six wire, 1 five wire and 1 three wire blocks.

From left to right, the dimmer, ground and power terminal blocks. The leads coming in from the top come from each gauge. Plus the ground terminal block also received leads from the signal and high beam indicators. Before I mounted these for real, I clamped everything to my test battery. As long as the gauges lit up, it means my terminal blocks are working properly.

The Factory Five carbon fiber back board curves in. this provides a shelf where the terminal blocks can be mounted. I mounted the terminal blocks using 3M double side tape. I had wire for the power and ground leads, but nothing for the dimmer block. I know I have some wire at the Northern Man Cave, so I'll take care of that when I get back.

The top three wires are leads from the GTM kit supplied indicator lights. The bottom wires are leads from the speedo gauge. Since I have a terminal block, it should be fairly easy to run these leads into the steering column circuit. I probably am going to need another terminal block to handle signals coming from the front and rear of the car.

The speedo gauge has two white wires and a brown wire. The instructions says that the white wires are labeled on the gauge printed circuit board as left and right. In agate-agate you can barely make out something that looks like right. The left and right white wires are connected to the respective turn signals. The brown wire is connected to the high beam indicator. Somewhere along the line these have to be wired into the switch on the steering column. 

Sending unit terminal block.

The final terminal block is for sending units. These connect as follows:

1. Green - Connects to the ignition coil or the direct tach output lead.
2. Blue - Connects to the water temperature sending unit.
3. Gray - Connects to the mechanical speedometer cable.
4. Yellow - Connects to the fuel sending unit.
5. Orange - Connects to the oil pressure sending unit.

Terminal block set up on the back side of the instrumentation cluster. This certainly makes  a lot more sense.

Intellitronix Create-a-Dash

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Major System Category: Electronics
Task: Install Intellitronix Create-A-Dash kit
Parts:

1. Create a Dash Kit
2. Istrument panel back board
3. Singal and High Beam indicators

Prerequisite Tasks: N/A
Additional Costs: $434
Time Requirement: 8 hours
Date Started: May 10, 2013
Date Completed: May 18, 2013
The instrument cluster has been something that has bugged me about the car from the beginning. I wrote a post in January 2012, discussing this issue. Basically, the GTM is a WOW car. The lines, the performance, the handling all combine to create something special. Then you get in the car, look at the gauges and go, "Huh?" One of the major complaints about the C5 and C6 Corvette generations is that the interior does not match the exterior. One of the knocks on the GTM is that some people don't bother to finish the car. GTM 402 will be finished, and part of that, includes the WOW factor.

This is a task best done on a bench. This multi angle Stanley vice is fantastic for this job. I have one at both the Southern and Northern Man Caves. In this photo it is holding the Factory Five carbon fiber backboard used to mount gauges. I taped it to protect the surface. I have also used this vice to help crimp connectors, and I can mount almost anywhere on the car or the lift.

In the January 2012 post, I looked at Intellitronix, Speed Hut and Dakota Digital. I also considered the all in one dash consoles with data recorders, but these were running over a $1000 and I just didn't like the look. This entire task is about the look. Around January 2013, I decided to take another look at the the instrumentation puzzle. I came across Intellitronix's Create-A-Dash kit. At first I rejected the idea, then I came to realize this was exactly what I was looking for. Then I saw it on Stacey David's Gearz program (for a car builder this is a good show for ideas).

I planned to work on the instrumentation gauges on my current hiatus at the Southern Man Cave. I drop shipped the Create-A-Dash kit via Amazon and packed the tools I needed for the task. The gauges are available in white, green, blue or red. I watched a fair number of videos. I didn't want white (it just seems blah to me). I thought I was going to order blue, but it turns out red worked for my eye sight better.

The kit includes everything pictured here: Speedo, tach, volts, water, oil and fuel, smoked Plexiglas cover, backboard  mounting hardware and sending units.

Each gauge requires eight spacers. You place the short ones against the base board and the longer ones between the gauge and the Plexiglas cover. There are a bunch of little bolts, nuts and plastic spacers for mounting. I poured them into a magnetic parts bowl. It is very easy to lose one of these small parts. Intellitronix recognizes that most of us drop things into to distant corners and includes extras!

To protect the backboard I cover it in blue painter's tape.  The locations of each gauge is marked  on the tape.

I super glued the spacers to the printed circuit boards. I know from experience that I don't do well with little parts, and anything I can do to make them easier to handle is worth the extra time.

I used the packing Styrofoam panels to support the gauges as I glued the spacers to the  printed circuit boards.

My first idea was to drill a hole behind each gauge, install a grommet and run the wires to the rear of the panel. This doesn't work. The wires are too stiff to be bent so they can fit through a hole hidden by the gauge. I ended up drilling a hole for individual wires and cutting a slot for groups of wires.Once the smoked cover is mounted, these details are obscured.

The back side of the fuel gauge. The four wires coming off the end can not easily be bent to go through a hole, so I just let them go straight to the back board, where there is more room and slack on the other side.

I did a fair number of measurements to make sure I had things lining up properly. The bigger gauges measure 3.25 x 3.25 inches. They are smaller than the round five inch gauges and they use space more efficiently. The smaller gauges are 1.625 x 1.625 inches versus a two inch round gauge. This allows me to easily deploy six gauges on the back board with space to spare.

Gauge set set in place on the back board. You can see the lines I drew to help me  get things set up. I worked off a center line. The center line is approximate, because the Factory Five back board is already cut and it seemed like the curve is slightly different from side to side.

There is some wiggle room for mistakes, but I tried to keep those to a minimum. Prior to drilling and holes and cranking bolts, you can get a good idea how things line up. The wires are stiff enough to support the gauges. I used a 5/64 bit to drill through the holes on the printed circuit board and into the back board. then I widen the holes on the back board with a 7/64 bit. I rifled through my Allen wrenches until I found one that fit into the head of the supplied bolts. The 1/4 inch nuts on the back side are easily handled with a ratchet.

Gauge set bolted in place.

The multi angle vice really came in handy. I could turn, spin and position the back board all different ways. There is no specific torque spec here, so just use common sense.

I couldn't resist. I hooked everything up to my 12v test battery. Note: If you get confused on the little gauges, just hook it up to a 12v source and they will tell you what they are.

The next part involves cutting the smoked Plexiglas cover. The kit provides a generous piece. You could almost get 2 covers out of a single piece. I positioned the Plexiglas sheet behind the factory Five back board, and held it in place with duct tape. I traced the curve. I discovered things here are not perfect either. I used a jig saw to cut the piece, then steel wool to smooth out the edge.

Cut Plexiglas piece.

I decided to use three bolts to attach the cover to the back board. I made a quick trip to Home Depot and picked up bolts, nuts and spacers. I trimmed the spacer to 5/8 inch. This way  did not put any pressure on the gauges or the bolts holding them in place. I installed the connecting bolts on each side and on the center line between the speedo and tach gauges.

Hardware to connect the screen cover to the back board.

There remains the problem of the little toggle switches on the tach and speedo gauges. I hit on the idea of looking at the switches sideways. I used a straight edge to run two lines and plot the intersection point. Then I drilled a large enough (5/16 inch) so the switches could go up, down, left, right.

The circle is where the toggle switches come in contact with the cover. I was able to eyeball the location of the toggles with the aide of a straight edge. Once I had an intersecting point, I just had to drill a hole.

The final step is to install the high beam and signal indicators from the Factory Five kit. I decided these needed to be mounted on the surface of the cover, because they are not as bright as the Intellitronix gauges. I  wrapped the wires in electrical tape (I should have brought some black from the Northern man cave) and ran the wires from the cover through the back board. I super glued the indicators for extra security.

The wires are wrapped in green electrical tape. The signal  indicator is surface mounted on the cover.

Next steps involve adding a wire block to the back of the back board to handle all the wires and fabricating a gasket to run along the edge of the between the cover and the back board.

Not the greatest photo, but you can see the high beam and right signal indicators.