Coralba C Rally or GIANT Wiring

I realize this is an old thread, but I just wanted to post up the answer to the original question in detailed as I've disassembled a completed loom and have an electrical engineering background to explain what is going on:



Serial pins:

1. Fuel level (BLACK) - in my diagram, and in the original image, a 181 resistor is shown which provides the necessary voltage divider when the OEM fuel gauge of the car has been disconnected. Fuel level sensing provides a resistive ground path, and 181 ohms to +12 VDC is a very commonly used OEM resistance.

If you retain your OEM fuel gauge wire, or if you have a fuel gauge wire that connects to the ECU (generally, OEM ECU), the resistor can be omitted.

2. Trip 1 reset (WHITE) - can also be customized to other function on C-Giant, but it is a grounding momentary switch.

3. +12 VDC [BATT] (RED) - should not be run on IGN power but rather BATT power (through separate switch + 1A breaker) to retain programmed settings.

4. Speed sensor wiring to 5-pin DIN connector - note, my pin numbering convention used on the 5-pin connector in the diagram is WRONG; looking into the connector, I numbered them 1,2,3,4,5 when the proper order is 1,4,2,5,3. On many Coralba speed sensors, only pins 1-3 are used - the fourth populated pin is only required if the speed sensor requires +12 VDC.

5. Reverse switch *OR* second programmable function (YELLOW) - in my example, the wire goes to a 4-pin connector for a remote switch. I do not have a remote switch, but I will describe how it works and why I have 4 wires entering the connector:

WHITE function - requires ground wire and white wire; functions identically to the trip reset switch in #2. Pressing this switch triggers Trip 1 reset *OR* whatever WHITE function you've programmed into the C-Giant.

YELLOW function - requires ground wire, yellow wire, and +12 VDC; inside the switch, there is a pull-up resistor connected between the yellow wire and +12 VDC. The momentary switch is connected between the yellow wire and ground. Pressing this switch triggers whatever YELLOW function you've programmed into the C-Giant.

6. +12 VDC [BATT] (RED) - should not be run on IGN power but rather BATT power (through separate switch + 1A breaker) to retain programmed settings.

7. SEE #4

8. Ground (BROWN) - colored blue because I don't have a brown sharpie

9. SEE #4

The speed sensor I am using is the standard GpN module that has a 3-pin DIN male connector to the C-Giant and a 1-pin input from the VSS signal wire from the car. The 5-pin DIN female connector coming from the C-Giant is necessary to cover the dozen (or more) speed sensors available from Jemba, although in the worst case, only 4 of 5 conductors are used.



Edited 3 time(s). Last edit at 01/15/2019 12:16PM by mrsaturn7085.

Thank you mrsaturn. Good information for many worldwide.

To clarify the 5-pin DIN numbers and a corrected circuit:






Edited 1 time(s). Last edit at 01/15/2019 07:16PM by mrsaturn7085.

Quick update - all the wiring I noted has been validated and is working on my L4WD car. As noted, clipping the 181 ohm resistor was necessary to maintain a functional OE fuel gauge on my main cluster and the only additional detail to note is that fuel calibration is a bit of a pain when you use an OE fuel gauge cluster (depending on vehicle make). Having a dual level sender 'saddle' fuel tank makes things even more interesting.

In short, between each of the 5 fill stages during the Coralba fuel level calibration, you have to cycle the vehicle IGN because most mid-90's and later OE cluster gauges have a microcontroller that will not adjust the electrical signal to accommodate tank filling while the IGN is on (i.e. the OE fuel gauge will not move without cycling IGN and therefore the Coralba will not sense a change in the signal, either). The trick here is keeping your Coralba unit powered while cycling the IGN, being patient, but not being too patient to the point where the Coralba screen goes to sleep.

If you got this far on your own, that will probably be enough to sort it all out. Good luck!