switch?????

[30 a truck]

Let me start by saying that I did not disassemble this truck. When I removed the old wiring harness from the firewall, the entire harness came out. Everything was loose except the fuse panel. This switch came out with the harness. I am installing a new AAW harness (nice). Where does this switch go??? It is not the neutral safety or brake light. I see no way or no how it could have been 'rigged" to be a park brake light. Help?

[Andy4639]

I have never seen that before in one of these model trucks. It could be some kind of brake switch but it's not factory to these vehicles.

[midniteblues]

Looks to be a turbo 400 trans kick down switch. It mounts on the gas pedal bracket.

[30 a truck]

When I got the truck, it had a TH350 with it. Spid says M49. Is M49 TH400?

[midniteblues]

Originally Posted by 30 a truck

When I got the truck, it had a TH350 with it. Spid says M49. Is M49 TH400?

Can't help ya there that's a question for the spid gurus.

But if there was wireing going to it I would say it was a 400 truck. Or if there was no wires perhaps someone installed the gas pedal bracket from another truck an just didn't remove the switch.

Pretty sure the earlier trucks had a switch mounted at the carb linkages.

[engineer_gregh]

I've read several threads that state M49 could have been either a Turbo 350 or 400. The picture looks like the kick down switch for the Turbo 400 to me.

[LockDoc]

-
Take a look at this older thread.

http://67-72chevytrucks.com/vboard/s...d.php?t=319667

It also shows the optional Manual Throttle hooked up.

LockDoc

[snipescastle2]

Ditto on the 400 TH kick down switch....
Ben

[davepl]

Lockdoc wins, part of a manual throttle knob setup.

[30 a truck]

Asking because I don't know. If it is manual, what does the power do? It has a place for 2 wires.

[davepl]

User pryorstemmed has one and had to hook the wires up, but didn't post how he did it, you might try him.

As a random guess, maybe it's another "step" in the neutral safety so you can't start it when the hand throttle is engaged?

[cleszkie]

The switch has nothing to do with the manual throttle. The switch is the TH400 kickdown, as several folks have already pointed out.

[davepl]

Originally Posted by cleszkie

The switch has nothing to do with the manual throttle. The switch is the TH400 kickdown, as several folks have already pointed out.

Are you saying that even trucks without manual throttle use that same switch on the pedal assembly to sense kickdown?

My TH400 kickdown looks nothing like that in 1970. But that switch looks EXACTLY like the switch on the manual throttle bracket for 70 or later (the 67-68 was a cruder system with no switch). So maybe it's part of the kickdown only and just happens to be on the same bracket?

I'm not disputing you - it could well be that the picture of the manual throttle includes it in the photo but that the bracket part is ALWAYS present even without the manual throttle and we're just looking at it as a unit incorrectly. So perhaps that whole piece of it is always there and the manual throttle cable is just added to pull (while in 67-68 it went through the firewall).

[cleszkie]

The style/mounting location of the kickdown switch might be dictated by whether a manual throttle was included on the gas pedal bracket or not. I don't know.

All I know is that the manual throttle simply pulls the accelerator pedal to the desired location and holds it there. It has no mechanical or electrical connection to the kickdown switch. I can think of no reason why it would. I have a manual throttle on my 72 Blazer. I use it to set and hold my rpms up while in neutral to generate more current for my electric winch. Folks with PTOs use it to increase rpms in neutral to increase hydraulic pressure.

[LockDoc]

-
The switch and manual throttle are two completely different things. Neither has anything to do with the other, they just happen to be mounted on the same bracket in '71-'72. The one wire from the kickdown switch goes to the TH400 Transmission to electronically shift it into passing gear when the pedal is floored.....

LockDoc

[davepl]

Originally Posted by LockDoc

-
The switch and manual throttle are two completely different things. Neither has anything to do with the other, they just happen to be on the same bracket in '71-'72. The wires from the kickdown switch go to the TH400 Transmission....

LockDoc

Thanks! Makes more sense. On my '70 the kickdown is under the hood, so it didn't make sense on first impression.

[LockDoc]

Originally Posted by davepl

Thanks! Makes more sense. On my '70 the kickdown is under the hood, so it didn't make sense on first impression.

I edited & added to my last post....

LockDoc

[Andy4639]

I have looked at hundreds of these trucks and have never seen this part! So I learned something new to! All the kick downs I have ever seen where out in the motor compartment!

[30 a truck]

I learn something just about every day when I visit this site.

I also learned that not all parts go with the truck you find them in. I am still puzzled as to why this 400 kickdown was in this truck. Oh well, life goes on.

Thanks for the help guys.

[Boog]

As old as these trucks are we'd be foolish to assume any part of them is original from manufacturer unless we are looking at a fully documented original owner vehicle and even then there is still a smidge of doubt to be had.

[midniteblues]

Originally Posted by 30 a truck

I learn something just about every day when I visit this site.

I also learned that not all parts go with the truck you find them in. I am still puzzled as to why this 400 kickdown was in this truck. Oh well, life goes on.
.
Thanks for the help guys.

Little off since your truck is a oe 350ci.not very common to back up a 350 with a th400.

Was there a branch in your harness that plugged into it????

Guys I don't think we will ever stop learning something new when it comes to these trucks

[30 a truck]

When I pulled the old harness out, nothing was hooked up, just screwed to the firewall. This switch had 2 brown wires connected to it. The other end was just hanging, already unhooked.

No big deal as I am adding a new AAW harness. I don't need this switch now that I know what it is.

Thanks for all the help. This thing is a breeze to wire compared to the last one I wired.

[midniteblues]

That's a sweet ride