Can you tell what this is????

[skydiver]

Hey Yall,

Noticed this connector hanging down from my engine. Can anyone tell me what it is? I have followed it up and it disappears into the harness somewhere. For sure it is not a vacuum line.

skydiver

Heres a picture. It is the black connector near the bottom.

[Longhorn Man]

was your truck originally a manual shift tranny, or was it always an automatic?

[Indyuke]

I have the same exact connector on mine too, and I have no idea what it goes to. I'll have to watch this thread.

[Longhorn Man]

wait... after looking again, I am almost sure that goes to the electric kick down on the tranny... TH400?

[skydiver]

Just bought the truck last year. I assumed it has always been an automatic but after checking the option list it show that it came with a turbo hydra-matic code M49. Checking online this option shows that it is a Manual 5 speed. Now I am very confused as there are no signs that the truck was a manual. No hole for floor shifter or column. Its a 72 so not sure where the shifter would have been.

[berencam]

is it long enough to reach the master cylinder, and is there already a wire going to master? it almost looks like the low fluid light wire.

[Longhorn Man]

turbo hydra-matic code M49 is a 3 speed automatic. That could be a TH350 or a TH400 in the trucks. Can you get a photo of the tranny pan?
The wiree going to the master cylinder would be brown

[Sinister]

Looks like it could be oil pressure dummy light or water temp dummy light. What color is the wire? You could cross reference the wire color with a wiring diagram...

[berencam]

Originally Posted by Longhorn Man

The wiree going to the master cylinder would be brown

thought so, couldnt remember if it was black or brown, the little rubber piece on the end looked familiar.

[skydiver]

OK. Here are more picts. The wire is not brown but it does looks a lot like the brown wire going to mater cylinder. Makes sense that it would be some sort of warning light. I just took off the pan so took pictures of internal also.

[Bus Ted Knuckle]

Looks like a th350 to me. must be for a dummy light, oil or water temp. Do you have wires already going to these? The brake warning wire isn't long enough to hang down that low...well, I guess someone could have cut the loom.

[boundstaffpress]

I had one on my chevelle. As I remember, it works with the transmission, the throttle anti-dieseling-solenoid and the vacuum advance. The whole system is called the TSC (transmission spark control)

There should be a sensor like a dummy light oil pressure switch somewhere on the passenger side of the transmission. If you no longer have the solenoid on the carb, there is no need for the lead to the transmission.

[Indyuke]

I was just thinking. The wire on my truck is unplugged and my back up lights don't work. Could it be the back up light wire?

[Dusty_case]

I think that is your backup lights

[Longhorn Man]

back up lights are wired up inside the cab, not underneath. That's why I was askin if it used to be a 4 speed, 4 speeds were plugged in underneath.

[GSFMECH]

That's the TSC, transmission spark control as said above. That wire was connected to a switch in the side of the transmission. What it did was not allow the vacuum advance to work until the transmission is in high gear. When the truck was new there was a solenoid mounted on the intake manifold and the vacuum source was routed from the carb through it to the vacuum advance on the dist. I've always disconnected them, it will run better without it.