I was wondering about that myself; in mine, there was one wire from the left terminal to nowhere, nothing on the second terminal. Might have been a ground at some point? The truck ran fine, and I did not use those terminal upon rewiring (I used one of the outermost lower screws to ground the instrument panel itself, easier to route than from the top terminals and less likely to slip off), the truck still runs fine. Sorry, not much help.
I too am curious. Is it a supplemental ground? I know that the gages do
odd things if he cluster is not ground properly. Unfortunately I don't think
my theory works because the Y wire is a ground too I think. Pinhead could
I'm sorry, I'm still a bit confused. Are you saying that there is an
additional light bulb called the "meter pilot light". I always thought
a pilot light was something on a furnace. I've never seen the wire
you show on the older instrument clusters. Sorry to be so dense.
SInce I have never taken the cluster apart to mod the cluster light bulbs I cannot say since I really didn't want to fool with the odometer area. I had other issues besides worrying whether I could see all the miles on my cruiser. I am assuming there is a light bulb in there. Maybe its like the ones on the old 120volt testers or something I don't know. But I'm sure there is a reason to have those wires there.
This is what I have.
Maybe the meter light is the instument light and if so I have no idea what it is for then. Take it apart and get back to us.
I'm thinking it is a light behind the needle or it's some sore of speed sensor for the emmissions computer. In another diagram I see it goint to the computer.
I am not sure the "meter pilot light" theory is correct; there is not a provision for another light bulb anywhere in my gauge cluster (1/72), and I can see all gauges just fine at night including speedometer. Also, my gauge cluster is lacking what is shown as the connector on the back to the orange wire; no round connectors, either.
Trollhole's appears to be a later model.
My husband suggested: "maybe it's a diagnostic port........"
So the jury is still out? Not that it matters in for my application because I can see my cluster just fine with the two lights. I'd go and figure it out but I just installed the cluster and it was a pita to get it in there.
Trollhole has a different type cluster but looks like one of the terminals is for a light...
I've some dangling wires about in there but they are all accounted for.
I've taken dozens and dozens of early model clusters out of cruisers for 20 years now, and NONE of the 72 and earlier cruisers [read:threaded speedo cable] have had those two pieces sticking up out of them.
I vote with Mark. I examined two of my pre-72 clusters last night and neither had
the little tab. Both were the type that use the screw-on type speedo cable and one
is almost certainly the original one from my late '68 cruiser.
It is a red/blue wire so I bet that it is a light of some sort (at the speedo head?) that
we early cluster types don't have. Are there three lights in the 1974+ cluster? I think
Mark hit it just right. Somebody replaced the speedo head in Trekker's '68 with a later
cluster (hey Trekker, what kind of speedo cable do you use, CLIP or SCREW).