Throttle Switch??
Thread Starter
Pro
Joined: Oct 2009
Posts: 582
Likes: 1
From: Massapequa Park New York
Throttle Switch??
i was just looking under the dash of my 75 and noticed a switch hooked up to the gas pedal. whats it for?? and my pedal doesn't even travel far enough to activate it.
What does this switch do?
What does this switch do?
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
On all the older cars I've seen with an automatic transmission the kickdown "switch" is a rod that goes from the tranny to the throttle linkage on the carb - everything's under the hood and nothing's in the passenger compartment.
My guess is that its a non-factory item added by the previous owner for some reason, maybe something like an engine kill switch as a security feature.
My guess is that its a non-factory item added by the previous owner for some reason, maybe something like an engine kill switch as a security feature.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
GM used an electrical switch for kickdown on a TH400 and a cable for TH350. The switch in question is very likely a kickdown switch for a TH400. Does it have a pink and an orange wire going to it?
Melting Slicks
Joined: Oct 2005
Posts: 2,056
Likes: 8
From: Redruth Cornwall
It is factory...
On my old 75, an auto, it was to do with both the kick down for the trans.....yes it was electrically operated, but it also does the cowl induction flap on your hood. IIRC, cables should be brown and black.
If it is still working, when you mash the gas, the switch operates a solenoid that opens the cowl flap to the rear of your hood.
On my old 75, an auto, it was to do with both the kick down for the trans.....yes it was electrically operated, but it also does the cowl induction flap on your hood. IIRC, cables should be brown and black.
If it is still working, when you mash the gas, the switch operates a solenoid that opens the cowl flap to the rear of your hood.
Last edited by jotto; May 5, 2010 at 05:42 PM.
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8th Gear
Joined: Jun 2009
Posts: 8
Likes: 0
Switching Gears....
I was looking for other info on this. I saw this switch in my 70. I want everything to work so I make sure it downshifts. Is has no carb hookup, so I was looking to confirm that it is electrical..I had a ford with a throttle body link downshift, but on the TH400 it is this switch. I looked in the electrical diagram and didn't see it, but it makes the most sense. It also makes sense to run it parallel with a cowl door if you have one.
God Bless,
Leon
God Bless,
Leon
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
If the switch is at the top of the gas pedal rod it is the switch that activates the door on the hood for the cowl induction. It energizes the solenoid in the hood when you go to WOT only. Otherwise the hood door is closed and intake air is injested from under the hood. Used on '73-'75 Vettes.
Turn the key to the on position and push the gas pedal to the floor. You should hear a click from the back of the hood as the solenoid opens the hood door. This switch is self adjusting and over the years if you have fiddled with the throttle cable or linkage the adjustment may be off and the switch doesn't activate the solenoid.
If so do this: with your thumb on the arm that sticks out of the switch, push up and toward the engine hard until you hear a snap. The next time you go to WOT the switch will self adjust and energize the solenoid. Some people put a piece of vacuum hose on the switch arm to get it to work but that is not necessary if you do the self adjustment thing.
Turn the key to the on position and push the gas pedal to the floor. You should hear a click from the back of the hood as the solenoid opens the hood door. This switch is self adjusting and over the years if you have fiddled with the throttle cable or linkage the adjustment may be off and the switch doesn't activate the solenoid.
If so do this: with your thumb on the arm that sticks out of the switch, push up and toward the engine hard until you hear a snap. The next time you go to WOT the switch will self adjust and energize the solenoid. Some people put a piece of vacuum hose on the switch arm to get it to work but that is not necessary if you do the self adjustment thing.
Pro Mechanic
Joined: Oct 1999
Posts: 3,918
Likes: 1,461
From: South-Central Coast California
So...if it's the switch that opens the cowl induction on a 73-75, why is the switch on a 70?
My wild-assed guess is the switch was used from 70-72 on cars with THM 400s and on all 73-75 regardless of transmission.
My wild-assed guess is the switch was used from 70-72 on cars with THM 400s and on all 73-75 regardless of transmission.
