TR4/4A Gauge Grounding Question tr4

[Dash]

It was necessary to ground the gauge lights independent of the daisy chain that connected to all the gauges (long story) but I just left that wire alone with no path to ground. Since it's no longer needed for the lights should I complete the ground to that wire chain anyway? Do the gauges themselves, i.e.: temp & gas gauges, still need that ground? I'm thinking not so would just like to verify.

 

[robmate]

It was necessary to ground the gauge lights independent of the daisy chain that connected to all the gauges (long story) but I just left that wire alone with no path to ground. Since it's no longer needed for the lights should I complete the ground to that wire chain anyway? Do the gauges themselves, i.e.: temp & gas gauges, still need that ground? I'm thinking not so would just like to verify.

Yes these gauges need to be grounded not just for the lights but also for them to work properly

 

[Sarastro]

The mechanical gauges of course need no ground to operate, but one terminal of each one's lamp is connected to the instrument's body, so it needs a ground to illuminate. The fuel and temperature gauges are electric and their bodies need a ground connection to work properly, but they need to be grounded anyway for the lamp. The ammeter does not need a ground to operate, but, again, it needs one for the lamp.

The instrument grounds were made through that "daisy chain" of connections, but how you do it doesn't really matter. As long as there is a path through the wiring from the lamp to the car's body, all is good.

 

[poolboy]

Whether the small gauges needs grounding for the lights, just depends. If the bulb holder which holds the bulb has 2 wires, the gauge does not need grounding to light the bulb...that's what the second wire is providing

 

[Sarastro]

Dunno about the TR2 and 3, but in the TR4 and 4A the gauge illumination lamps are all grounded through the instrument body.