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.