Spitfire Ok spit guys help me out here.

[DeltaAir423]

I was working on my spit (1980), and after I finished up with the routine stuff I had planned, I decided to tackle my inop fuel and temp gauges. Looks like the voltage stabilizer is bad, I tried cleaning the connectors and tightening the mounting screw. However when I put the speedo back in, and the ground wire on the speedo came out. Looks like it was previously repaired, and a new spade connector was intstalled however I don't see a loose mating connector anywhere. Can anyone trace this wire and ID where it's supposed to go?

 

[guzzul]

I'm confused. I didn't think the speedometer itself had a ground, per se.

Do you mean the ground wire for the voltage stabilizer? Or the tach? The only other ground wire on the back of the speedo is the one at the lamp, which has its black ground attached to the rim of the lamp holder.

 

[DeltaAir423]

On the inboard mount there's a ring terminal that is a ground wire. Even in the Bentley manual (88.30.01 step 5), they mention removing the ground wire from the mount on speedo removal. On the voltage stabilizer I'm only seeing 2 out of the 4 terminals used. There's a female connector with two light green wires attached to it goes to the fuel gauge and temp gauge, and a male connector with one dark green wire attached to it that runs to a connector somewhere that feeds the hazard switch and the tachometer. From the wiring diagram, it appears that the dark green wire is feeding the positive side, and the light green is providing a ground through the fuel gauge/sending unit and temp gauge/temp transmitter circuits.

 

[DNK]

On a the 6 there is a ground that jumps from gauge to gauge and is connected with a ring terminal at the hold down stud.

 

[guzzul]

Noting Don's post also, it seems that some were fitted with a ground. My BL manual describing removal of the speed says "Detach earth wire (where fitted)".

BL's manual, however, clearly shows an earth wire on the tach mounting clamp, and a gauge-to-gauge ground as Don points out would make sense.

Mine does not have one on either the speedometer or tach. I assumed the ground would come from the clamp itself pressing against the inner fascia metal.

The voltage stabilizer only uses those two terminals. The other terminals are common'd with the two used. Why they are there I have never discovered. The ground for the voltage stabilizer comes from its being attached to the speedo body. Note also that the body of the speedo illumination lamp will also provide a speedometer body ground, since it is basically 'plugged' into the speedo.

 

[70herald]

If I recall correctly someone is confusing you with the spade. There should be a loop on the end of the wire, and it is held in place by the speedo mounting nut.

 

[DeltaAir423]

If I recall correctly someone is confusing you with the spade. There should be a loop on the end of the wire, and it is held in place by the speedo mounting nut.

There is a ring terminal that is held in place by the mounting nut. What is throwing me off, is that there has been a repair done to the wire (badly I might add), ring terminal on speedo mounting nut, to black wire, to electrical tape to brown wire to a male spade terminal. I'll get pictures of the offending wire when I get a chance.