[jon greenwood]

Bought new top switch for my 65 gto . Connected to yellow wire. When mounted to dash get spark. Why ,?

[rohrt]

That seems wrong.

Disconnect the pump connector.
Then connect the power wire make sure there is no spark.
Then check there is no power at the connector to ground.
Then Test both up and down on the switch.

[John V.]

I am assuming '65 is similar to '64, I'm looking at the '64 convertible power top wiring.

The yellow wire is the Power Feed to the switch.

Although it is recommended in the Owners Guide, as best I recall, to run the engine while raising and lowering the Top, the switch is always powered so the Top motor will run with the engine off.

The ground is provided at the motor in the trunk. The motor is mounted on rubber bushings. I don't remember if there is a ground wire but pretty sure there is, it should be obvious when looking at the motor and its integral wiring at that end.

The switch position then determines which way the motor turns and consequently which direction the hydraulic fluid flows, so that the Top goes up or down.

When the switch is in the "neutral" position, no power is routed to the motor.

But the switch is always powered by way of the yellow wire. I don't think it even matters whether the ignition switch is on, only matters that the battery is connected and isn't "dead".

My own switch is a bit sticky so I have to be careful to be sure the motor is truly "off" when I walk away. Ive had to "coax" the switch to the "neutral" position on a couple occasions when the motor continued to run when I let go of the switch.

I don't know exactly where you are seeing a spark, but my impression is that somehow the repro switch is allowing power to connect to the body of the switch internally. The metal dash is grounded but I don't think the switch itself requires grounding. The spark would seem to be a result of the metal switch body conducting 12V and a spark jumps the gap as the switch body comes close to the dash.

I'm no electrician, but if the switch body is electrified by faulty internals, it would be at 12V and your body doesn't provide enough resistance to create a shock hazard, so you would not know by touching it that the switch body is powered.

You could check this by connecting the yellow wire to the 12V power source without attaching the switch to anything. Then use your multimeter to see if there is 12V between the switch body and the grounded metal dash.

There shouldn't be since the metal switch body should be isolated from the wiring (and power).

If you have a 12V light tester, you could also test the switch body by touching one lead to the switch body and the other lead to the dash, if the 12V bulb lights, the switch body is powered and it shouldn't be.

[bill ryder]

Excellent directions John. Glad I did not post anything similar!!!!

"Bill"!

[BOB VIDAN]

Bill, you're a little late on the draw most times.

[Singleton]

Originally Posted by jon greenwood

Bought new top switch for my 65 gto . Connected to yellow wire. When mounted to dash get spark. Why ,?

I had a similar issue with a reproduction top switch in my 64. Spark sometimes, switch would stick, not shut off. Cheap crap. I took it off and sourced an original used switch, no problems now

[MidnightAuto]

Repo switches do suck.