Pedal Mounted Kickdown Switch
Thread Starter
Advanced
Joined: Oct 2012
Posts: 81
Likes: 6
From: Montgomery Alabama
Pedal Mounted Kickdown Switch
The kickdown on my car is intermittent. I located the switch by the pedal and saw that when the pedal is full floored the switch is only about half way pressed. I added some rubber hose to the round part of the switch and that bought me about 1/4" of additional travel. Test drive still only had two times where it would kickdown and then nothing. Two issues I need help on:
1. Is the movement of the switch one continuous slide or are there two positions...my switch appears to move down past a detent and then return to that detent. Only with a little push from my hand does it return back to the fully closed (resting) position. Is that normal or should it have a smooth, full slide the entire length of the switch slide both directions?
2. Tied a piece of string to the switch and drove it...once it was cruising in third gear, pulled the string, activating the switch, nothing happened...no down shift. Should the tranny downshift whenever that switch is activated or does it also require some vac change when pedal is WOT?
With the key turned on I understand I should hear a click when the switch is activated...I do not.
So, bad switch?
1. Is the movement of the switch one continuous slide or are there two positions...my switch appears to move down past a detent and then return to that detent. Only with a little push from my hand does it return back to the fully closed (resting) position. Is that normal or should it have a smooth, full slide the entire length of the switch slide both directions?
2. Tied a piece of string to the switch and drove it...once it was cruising in third gear, pulled the string, activating the switch, nothing happened...no down shift. Should the tranny downshift whenever that switch is activated or does it also require some vac change when pedal is WOT?
With the key turned on I understand I should hear a click when the switch is activated...I do not.
So, bad switch?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The click is the solenoid in the trans opening. If you don't hear it there's a problem. IT's possible your switch is worn and the contacts are passing each other insode the switch. Too much travel.
Burning Brakes
Joined: Nov 2006
Posts: 893
Likes: 7
From: Orange Park Florida
You should be able to hear the detente switch in the tranny operate. You may need to check the wiring from the pedal switch down to the tranny. My kickdown never worked so upon investigating I found:
1. Over the years the gas pedal had been bent so the pedal switch was not fully operating (solution was to reach down and pull back/up on the gas pedal till the switch would become fully engaged)
2. The wiring plug at the tranny housing was broken so no current was reaching the detente switch (I replaced the plug and verified connections)
3. I had a defective detente switch (I replaced for <$20)
good luck
1. Over the years the gas pedal had been bent so the pedal switch was not fully operating (solution was to reach down and pull back/up on the gas pedal till the switch would become fully engaged)
2. The wiring plug at the tranny housing was broken so no current was reaching the detente switch (I replaced the plug and verified connections)
3. I had a defective detente switch (I replaced for <$20)
good luck
Thread Starter
Advanced
Joined: Oct 2012
Posts: 81
Likes: 6
From: Montgomery Alabama
I took the switch off the pedal mount. No continuity when switch moved. It comes apart pretty easy. The inside had dry gunk in it...looked like the slide grease was dry and hard. Cleaned it out and reassembled. Good bench continuity. Put back on pedal bracket, turned on key, activated switch, nice noticeable tranny click! Now I have nice kick down!
Thanks for everyone's help.
Thanks for everyone's help.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
I took the switch off the pedal mount. No continuity when switch moved. It comes apart pretty easy. The inside had dry gunk in it...looked like the slide grease was dry and hard. Cleaned it out and reassembled. Good bench continuity. Put back on pedal bracket, turned on key, activated switch, nice noticeable tranny click! Now I have nice kick down!
Thanks for everyone's help.
Thanks for everyone's help.
Had to do this to mine a few years back.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,579
Likes: 7,020
From: New Or-leens Loo-z-anna
I searched and found this old thread........
Does anyone have a "tip" for a '68 convertible that has been converted to a TH400....
There is no bracket-whatever on the accelerator pedal for a kickdown switch.....
Can I just install a switch there...or do I need a bracket?
(I am able to make up a wiring harness/no problem)
Thanks for any info.
Does anyone have a "tip" for a '68 convertible that has been converted to a TH400....
There is no bracket-whatever on the accelerator pedal for a kickdown switch.....
Can I just install a switch there...or do I need a bracket?
(I am able to make up a wiring harness/no problem)
Thanks for any info.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
I searched and found this old thread........
Does anyone have a "tip" for a '68 convertible that has been converted to a TH400....
There is no bracket-whatever on the accelerator pedal for a kickdown switch.....
Can I just install a switch there...or do I need a bracket?
(I am able to make up a wiring harness/no problem)
Thanks for any info.
Does anyone have a "tip" for a '68 convertible that has been converted to a TH400....
There is no bracket-whatever on the accelerator pedal for a kickdown switch.....
Can I just install a switch there...or do I need a bracket?
(I am able to make up a wiring harness/no problem)
Thanks for any info.
M
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Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
Just looked and it's another 68-69 only part 
Time to get out the welder and start some fab work
A quick look at some photo's and I'm not sure why a later model bracket wouldn't fit...
M
Time to get out the welder and start some fab work
A quick look at some photo's and I'm not sure why a later model bracket wouldn't fit...
M
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,579
Likes: 7,020
From: New Or-leens Loo-z-anna
I saw some switches on the web/I'll "re-look" for them.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
If you google
Corvette Original TH400 Automatic Trans Kickdown Switch w/Bracket 1968-1969
You'll find a bunch of pics of what an original one looks like (big city) and then compare with the later ones are a chevelle one, may work out for you.
With the number of guys doing the auto - manual swaps, there should be some available
M
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,579
Likes: 7,020
From: New Or-leens Loo-z-anna
I was only joking about the carb switch (although I have seen them)
If you google
Corvette Original TH400 Automatic Trans Kickdown Switch w/Bracket 1968-1969
You'll find a bunch of pics of what an original one looks like (big city) and then compare with the later ones are a chevelle one, may work out for you.
With the number of guys doing the auto - manual swaps, there should be some available
M
If you google
Corvette Original TH400 Automatic Trans Kickdown Switch w/Bracket 1968-1969
You'll find a bunch of pics of what an original one looks like (big city) and then compare with the later ones are a chevelle one, may work out for you.
With the number of guys doing the auto - manual swaps, there should be some available
M
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