Spartan V3 Lite - Chassis vs Heater Ground

Spartan 3 Lite
1

I am in the process of installing a JRP 14/1 Gauges Kit with a Supplied Spartan 3 Lite Module.
This is in a an old car with mechanical a mechanical fuel pump etc. so i have had to work around a few things.

I now have to plan the wiring for the O2 Sensor and Spartan. However I have run a Complete new BUS and Fusebox for the Gauges, Spartan and other Accessories like my aftermarket head unit.

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I have run a new line of 8mm2 Twin direct to the battery with a 60amp MIDI fuse and in the car a small 6 way ATS fuse block to individually fuse my devices. This block has a Negative rail also so Iā€™m running both a direct positive and negative from the battery.

Reading my Documentation from JRP and the 14Point7 Documentation i cannot work out the point of the separate heater ground and where I should ground it.

Based on this The spartan controller will not be connected to a chassis ground but a direct ground to the battery on the negative terminal of the fuse block, the same ground will be used for my JRP Gauge Kit. Where do i put the heater (White) wire, just a chassis ground to keep the potential different? I have a few large ground leads from the engine to the battery and the chassis.

any help here would be appreciated before i begin cutting holes or trying to run a white wire extension to the block directly.

UPDATE:
Doing some reading it has do to with there being a lot of noise potential off the white heater ground due to using PWM for the heating.

So if I ground the heater back to the CHASSIS (in my case the trans tunnel) and my JRP Gauge kit and the Spartan Power to the new -ve rail in my little fuse box, the potentials between them and thus the lower level voltage signal (0-5v) for the gauges should not see offset due to noise.

If anyone can provide input here that would be great.

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Most of the noise from the heater is countered by having separate heater ground and electronics ground wires coming out from Spartan 3.

However, if you ground both to the same point and that point has a very poor connection to ground then that will counter the counter,

In your setup it looks like you have a good connection to ground so you can ground both the heater ground and electronics to the same point and everything will be fine. You can double check by observing the startup voltages of 1.66v and 3.33v, if they deviate significantly from those voltages then likely you have a ground offset issue and you should ground the heater ground to the chasis.

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