Automatic Transmission Wiring

[Vinn]

Hey all,
A while ago I posted a topic about the kickdown switch not functioning on my TH400 transmission. Also, the reverse lights do not work on the car. And finally, the ignition key lock does not seem to work.

I began to think, are all of these three related? The assembly manual for 1970 is vague on the automatic transmission wiring. Could there be some connection or fuse that would cause all three of these features to not work? (I'm pretty sure every fuse in the main fuse box is good).

If anyone has any suggestions on a solution, or on how to learn more about the wiring on this car it would be greatly appreciated.

Vince

 

[wishuwerehere82]

If my memory serves correct, there are no electrical connections to the TH400. There is a mechanical linkage from the throttle to the kickdown valve in the transmission, and a vacuum link from the intale manifold to the vacuum modulator, but nothing electrical.

I believe the reverse light switch is in the shifter in the console.
Someone correct me if I'm wrong.

 

[dman]

turbo 400 has elect swith at gas pedal and selinod @ left side a/t case . passing gear .kickdown... allso has vac mod valve ./ and gov assmby ....reverse lamps swithed at netural safety switch in consol ...... insp for power @ selinod wire @ trans,, under car .. , Ign switch on .,. eng off ... mash gas pedal to floor you should have 12 volts @ selinod wire ..if this is so. then listen to selinod click when power is suplied ..if selinod clicks pos inturnal prob or stuck selinod pin...???as for key lock . insp colom key lock cable @ colom under the hood .. pos binding or miss adj ..????? ps no mechenical kick down shift rods .thats ford stuf....chevy went to cable kick down much later on..

 

[JohnZ]

The Assembly Instruction Manual and the GM Chassis Service Manual both have complete car wiring diagrams, and a much larger plastic-laminated wiring diagram is available from Lectric Limited ( www.lectriclimited.com ). The manuals also have the adjustment procedure for the transmission linkage backdrive cable to the steering column that controls the column lock function of the ignition lock cylinder.

 

[Vinn]

Thanks, problem I've had is all of the wiring diagrams are for a "base" car, which doesn't help me learn how all of the electrical features of the automatic (RPO M40) work.

Vince

 

[GTR1999]

Vin, I just rebuilt a TH400 out of a 72. THe only wiring on that is the switch on the side, in this case it's a 2 prong for the TCS system. I believe yours will have only a one prong connector?

 

[Vinn]

Okay, I'm one step in the right direction. I fixed my reverse lights tonight. I took apart the switch attached to the gear selector in the console. There are four wires on it, green, pink, purple and purple. The green and pink control the reverse lights. I'm curious, what do the purple wires do? Anyone familiar?

Thanks!

Vince

 

[wishuwerehere82]

The purple wires are for the neutral interlock that allows the starter to engage when in park or neutral, but not in any other gears.

 

[dman]

purple wires for cranking starter.... switch .open in rev. drive.and 3 2 1 ..power flow or closed in park or netural ../ note to self must post faster....

 

[Vinn]

Thanks for the quick reply!

So it looks like I'm figuring things out...

These Work:
Reverse Lights
Neutral Interlock

These I've started on:
Kickdown Switch
I received some advice on this in an older thread:
http://www.corvetteactioncenter.com/forums/showthread.php?t=54154&highlight=TH400


These I have yet to look into:
Key lock (I'll follow dman's advice on this tomorrow)
A question on the key lock. If I turn the key to the RUN position, shift the car into gear, then turn the engine off, the key shouldn't come out with it still in gear. Correct?


I'm getting there! Before I bought this car I had no idea how complex the electrical system was on such an old car! I hope this information helps someone else out with an older automatic transmission.



Thanks all,
Vince

 

[wishuwerehere82]

Racing is in our blood! We just can't help it.
Good thing one of us know something about the TH400.

 

[Vinn]

Wow, I've never had so many people jump at all of my questions at once! How great! You know, I should've tried to start the car after I tore apart that switch... with my luck I messed up the purple wires after fixing the other two

 

[wishuwerehere82]

Thanks for the quick reply!

So it looks like I'm figuring things out...

These Work:
Reverse Lights
Neutral Interlock

These I've started on:
Kickdown Switch
I received some advice on this in an older thread:
http://www.corvetteactioncenter.com/forums/showthread.php?t=54154&highlight=TH400


These I have yet to look into:
Key lock (I'll follow dman's advice on this tomorrow)
A question on the key lock. If I turn the key to the RUN position, shift the car into gear, then turn the engine off, the key shouldn't come out with it still in gear. Correct?

The key will turn off, But the lock will not go back completely to the center position, or at least it shouldn't.

I'm getting there! Before I bought this car I had no idea how complex the electrical system was on such an old car! I hope this information helps someone else out with an older automatic transmission.
It's a Corvette. There are no easy parts on it anywhere!



Thanks all,
Vince

Good luck!

 

[Robin7TFour]

hello all. is there any way to adjust the kickdown switch. i have to mash the pedal hard to get any response.

Robin

 

[Vinn]

Robin,
The switch is adjustable. You should be able to reset the switch by pulling the button where the accelerator pedal makes contact with the switch all the way out, then slowly press the gas pedal once. This should do it..

Vince