kick down switch connector for '73 TH400
 

Greetings,
I'm saddened to say that I've been living without this for several years. :sad:
Soon after buying my '73 convertible (awesome drive home, btw, Atlanta to San Diego!) I noticed a wire hanging from under the car near the tranny. The previous owner was clueless and thought it was part of a long-disfunctional alarm system. Pretty soon the wire connector disappeared and I realized it was the kickdown connector to the tranny!!! Since then I have been very unsuccessfull at finding a connector to this. Local vette shops and Chevy dealers tell me to go dig around some junk yards...but that doesn't work too well for me. All the catalogs carry this connector for earlier C3's, but apparently something changed in 73. There's 2 wires (black & orange) that lead to the driver's side of the TH400 that is the kick-down connector.
Anybody got any clue where I can get a new/used/third-party-replacement for one of these????
Any help is appreciated.
Thanks,
John.

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

Is the connector unique to '73 or to the TH400 tranny? There are tons of cars running that transmission. I had kickdown issues with mine too but it turned out to be at the switch under the dash.

I assume you have tried all the major resellers (Eckler, Zip, CA). Maybe Tom73 could help out, he knows everyhting about '73s.

Good luck! :thumbs:

Re: kick down switch connector for '73 TH400 (Mystery Machine)
 

I had kickdown issues with mine too but it turned out to be at the switch under the dash.

That is the switch to open the cowl in the hood on my 74

Re: kick down switch connector for '73 TH400 (Freepop)
 

The black wire goes to the hood and the orange wire goes to the trans on my 73. The plug is a plastic peice with a spade connector mounted in it. You should be able to use a striaght spade connector to hook up to the trans. I can send you a picture of mine if you need it. send me an E-mail if you do.

Re: kick down switch connector for '73 TH400 (redwingvette)
 

That's right. Even though the connector has two slots, there is only one (orange) wire. If you look at the tranny there is only one spade and a standard plug fits on it. Just buy an insulated connector from NAPA or radio shack. Joe

Re: kick down switch connector for '73 TH400 (redwingvette)
 

:iagree: As redwing says a standard female spade connector is all you really need. That connector on the side of the trans is not actually the solonoid. Its just a junction for the wire to pass thru the case. On the inside the wire continues to the front of the valve body and connects to the kickdown solonoid. It gets activated by the switch above the gas pedal. Same switch also opens the cowl flap. I removed my cowl flap so it dont matter anyway. Theres quite a big difference in the automatic function of the trans when the kickdown is working corectly. its definatly worth fixin. Even if you need to pull the pan and replace the solonoid. i had to rig my pedal switch and replace the solonoid before it all worked right. Again it dont matter anymore since the 400 is on the floor in the shop now.

Re: kick down switch connector for '73 TH400 (Jvette73)
 

My 75 was not downshifting, so I check the voltage going to the solonoid switch at the trans. It was getting voltage but no clicking when ignition was on and acel depressed. (Without the engine running you should hear a click for the trans and the cowl hood induction when acel depressed). I opened the pan and removed the switch. Upon examination I found the wire lead to the maget had worn off the insulation and was grounding out on the casting. $30 for a new switch and I have what feels like 50 more HP's. By the way I fixed the original switch to keep as a backup.

Re: kick down switch connector for '73 TH400 (redwingvette)
 

I pic would be great, since mine is gone and I'm working from memory. But I know I have both black & orange wires hanging together where the plug used to be. So I'm confused about the black going to the hood. I thought I saw in the electrical diagrams that this black was some sort of ground and that's why I figured a special plug was needed (to ground to the tranny housing?). Anyway, thanks for the info, I can try a normal spade connector.

Re: kick down switch connector for '73 TH400 (joe73vette)
 

Definitely the tranny has just one spade, but I've definitely got 2 wires (black & orange) leading to my (missing) plug. I can try a std. connector to see how it does.
Thanks!

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

My 74 only has the Orange wire going to the trans. As others have said, the black one goes to the hood. dont worry about the black one for now. Hook up the orange, it will fix your tranny problem.

Re: kick down switch connector for '73 TH400 (Jvette73)
 

:iagree: I just fixed mine, and what a difference :jester My car was also upshifting too quick (3200rpm) and would not kickdown at WOT. Now it shifts at 4500....much better...

Re: kick down switch connector for '73 TH400 (desi)
 

Anyone got any tips on the installation and adjustment of the kick down switch on the gas pedal?
I have to re-install mine shortly and the AIM seems a bit vague....

thanx,
Nick

Re: kick down switch connector for '73 TH400 (lvrpool32)
 

On my 74 I noticed that the gas pedal rod was just barely activating the switch. I imagine that over the years the gas pedal rod gets bent out of shape somewhat (It is basically a L shaped rod that pivots at the corner of the L shape). I was able to grab a hold of the bottom of the gas pedal rod and pull up a little at a time to bend it back into its proper postion.

I kept bending it up slightly until the gas pedal rod made good contact with the switch. Worked like a charm and transmission is shifting down exactly like it should again. I have also heard of members of the forum, placing a piece of rubber hose over the horizontal post of the switch to bring it in closer contact with the gas pedal rod.

Ron

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

Here is the wiring diagram for the kick down. It shows a black and orange at the trans solenoid, Orange is the power, Black is a ground.

http://www.corvetteforum.net/c3/vette73/wireauto.jpg

73 Wiring Diagrams

Hope this helps somewhat. :)

tom...


[Modified by Tom73, 6:07 PM 8/5/2003]

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

I did some looking into this when I was rebuilding an engine. If I remember correctly, one of the wires you need is for the kick-down solenoid in the trans, which is indeed controlled by the switch above the gas pedal, and the other is part of the TCS system. I think TCS stands for Transmission Controlled Spark. It was something to do with the timing and trans shift patterns depending on engine temp. If you look at the passenger side head, between the rear two spark plugs, you should see a device screwed in there that has two connectors on it. That is a switch that either grounds or opens depending on the coolant temp. It controls a solenoid that affects timing by messing with the vacuum signal to the advance can, and also affects a solenoid or switch within the trans to do something to the shift pattern. That would be the second wire you are talking about. There should also be a timer of some sort on the firewall near the brake master cylinder that also affects the system by limiting the amount of time the system was in effect. These things all work together as part of the emissions controls.

Re: kick down switch connector for '73 TH400 (redwingvette)
 

Thanks a bunch! (for the advice and the photo too)
I left the black wire dangling, and connected the orange as suggested.
The result... :yesnod:
Johnny is a happy camper again. I had forgotten how truly responsive that baby can be! So easy to reconnect too.
Great forum, great advice.

John.

Re: kick down switch connector for '73 TH400 (Jvette73)
 

Thanks for the info - you were correct and the kickdown is working great now.
Can you tell me more about the cowl flap?
Is it a pretty common thing to remove this?
I have been wondering if mine is really functioning.
Anybody else remove theirs?

A newbie loving this forum,
John.

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

The purpose of the "flap" is to let cool air in to help increase power on accelloration. To have it open all the time would be a good thing for performance. You can see if it opens by opening the hood and looking in there while someone steps on the gas pedel.

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

I removed the flap and blocked the snorkels. Now all air must always come from the cowl

Re: kick down switch connector for '73 TH400 (johnnybrewmeister)
 

You can have the switch from my 72. Email me and we'll arrange it.