Dash Gauge Grounding

[memphis]

Hi All,

My fuel gauge was a bit loose, so I tighten up the thumb screw. As I was doing this, I noticed that the gauge light ground wire has a eyelet and is connected between the gauge bracket and the thumb screw. Seems like a logical place to ground, except that the metal bracket butts up against the rear "wood" dash panel. Not a ground at all?
How should the gauge lights be grounded, connected?
Thanks,
Bob

 

[RAC68]

Hi Bob,

The fuel gauge ground is in series with the rest of the gauge grounds and is delivering the ground through the post to the metal housing of the gauge.

All the best,

Ray (64Bj8P1)

 

[Keoke]

I noticed that the gauge light ground wire has a eyelet and is connected between the gauge bracket and the thumb screw. Seems like a logical place to ground,

--Yep because the grounding wire is routed back through the harness to a chassis ground.

However, an internal tooth washer placed on the stud between the knurled knob and the ring connector will help keep the conection tight-Fwiw--Keoke

 

[memphis]

Guys, thanks for your replies! It's fun to learn about how these cars were built and how they operate. A lot different than the W113 280SL that I spent years rebuilding. Very different, but the Healey is a cool car!
Thanks again,
Bob

 

[AUSMHLY]

I may be wrong here, so others will chime in to say so if I am.

I think the ground wire that attaches to the gauges, only affects the working of the light bulbs.

Cheers,
Roger

 

[Keoke]

I think the ground wire that attaches to the gauges, only affects the working of the light bulbs.

ROGER.

Where the case of the gauge also requires grounding it is handled using the same circuit.---Keoke

 

[AUSMHLY]

I removed the ground wire from my tachometer to test if the ground wire affected the performance of the tachometer. It did not. What I found was that the light bulb would not light up if no ground wire was attached.

Would not having a ground wire attached to the fuel, oil/water and speedometer gauges affect their performance, other than not allowing the light bulb in those gauges to work? Would one get an electric shock from the gauge if not grounded? What is the purpose of grounding the gauges other than to light up the bulb?

 

[Keoke]

Would not having a ground wire attached to the fuel, oil/water and speedometer gauges affect their performance, other than not allowing the light bulb in those gauges to work?

Some Yes others no.For example the fuel gauge utilizes a case ground.

Would one get an electric shock from the gauge if not grounded?

No 12 Volts DC will not shock you. However, it can give you a severe burn if a piece of jewelry you are wearing short circuits the 12 Volts to GND.


What is the purpose of grounding the gauges other than to light up the bulb.

To utilise the chassis as a low resistance return eliminating a long higher resistance wire.

Nite now--Keoke