Switch pitch and kickdown wiring

[kdml]

I have done a lot of reading online and the service manual to identify any issues with my switch pitch and kickdown wiring.  My car is getting close to being road ready and I would like to head off any issues before getting it back on the road.  Sorry for the long story, but I wanted to provide all the information I have gathered to help determine what problems I might be having.

 

I started by making sure the kickdown switch (detent solenoid) on the carburetor and the switch pitch microswitch (stator control solenoid) are properly adjusted according to the service manual. 

 

Next I moved to the transmission to ensure all the solenoids in the transmission were working correctly.  I applied 12 volts directly to the connector on the outside of the transmission.  I heard the solenoid in the trans click when applying voltage to the horizontal tang (switch pitch) on the connector, but nothing when applying voltage to the vertical tang (kickdown).  This could be my first problem.  Should I hear a click when applying voltage to the vertical tang on the connector? 

 

Next I moved on to the wiring.  Using a test light with the key on and engine off, I tested wiring at the plug which attaches to the connector on the side of the transmission.  I inserted the test light into the slot for the vertical tang (kickdown).  There is no power to this slot, unless I move the carburetor to full throttle.  I believe this is correct as that is when the transmission should kick down.  I then repeated the procedure for the slot for the horizontal tang (switch pitch).  I had power to this slot all the time, regardless of throttle position.  I double-checked that the microswitch on the linkage was opening just off idle, which should eliminate power to this slot.   This is potentially a second problem. 

 

To narrow down what was causing the second problem. I moved up to the switches on the carb and linkage.  There are 3 wires running to the kickdown switch (see picture).  If I am following the path of the current correctly, the orange wire brings power to the switch from the wiring harness on the firewall.  I am getting power to this wire all the time.  The yellow wire sends power to the vertical tang (kickdown) on the transmission.  I am getting power to this wire only when at full throttle,, which I believe is correct.   The black/yellow wire brings power to the horizontal tang (switch pitch) on the transmission.  I am getting power to this wire all the time, regardless of throttle position.  This is not correct as it should only have power at idle. 

 

To determine whether the switch pitch microswitch, on the throttle linkage is my problem, I disconnected the plug on the kickdown switch that runs to the microswitch.  I connected a jumper from the tang for the orange wire to the plug.  This should bring power to the microswitch.  I inserted my test light into the other slot in the plug and operated the linkage.  Power goes off as soon as I move the linkage.  This proves to me that the microswitch is operating correctly.  This leads me to believe I have a problem with the kickdown switch.  I tried to verify this by leaving the microswitch plug disconnected and testing power to the tang for the black/yellow switch pitch wire.  There is power all the time.  Does all this make sense?  Can the kickdown switch alone provide power to the switch pitch wire all the time?  Is this kickdown switch serviceable or does it need to be replaced?

 

Thanks

Doug

[RockinRiviDad]

Nice write-up of your troubleshooting. Your description sounds logical. I “think” u have the pathway correct.
 

I can say for certain that u CAN service your kickdown switch because I did it to mine. It was soooo simple but I had help. A transmission guru friend made a house call to help me sort this out. 
 

The switch body is made of a soft type of metal. U can see that on the back side of the switch where the circuit board is mounted the edges of the switch body are folded/bent (there is a better term for this but I forgot it haha) over creating tabs to hold the circuit board in place. My buddy had me pry those out of the way. Two tabs played nicely & I had to take my Dremel to the other two tabs. Then the switch simply pulled apart, we inspected it, all was in good order. We cleaned, lubed with dielectric grease, reassembled, bent the two tabs back into place & created two new tabs with a small tipped screwdriver & small hammer which I had removed with my Dremel 

[arnulfo de l.a.]

Here you go . This is what David is talking about. Took mine apart too because my kick down was not working. The Kick Down sends power to the micro and the micro sends power to the converter at idle so you don't get that creep at a stop. Then at part throttle the kick down sends power to the converter again , this time directly ,bypassing the micro. At full throttle the kick down switch sends power to the tranny kick down solenoid as well as power to the converter. Hope this helps

[arnulfo de l.a.]

Wanted to mention that the top picture is the position of the kick down at idle. You can see how power is being fed to the converter thru the micro in this position, then directly at mid point which would be part throttle. The bottom picture show where the contractor would be at full throttle with both the converter and tranny kick down solenoid receiving power.

[RivNut]

2 hours ago, RockinRiviDad said:

Nice write-up of your troubleshooting. Your description sounds logical. I “think” u have the pathway correct.
 

I can say for certain that u CAN service your kickdown switch because I did it to mine. It was soooo simple but I had help. A transmission guru friend made a house call to help me sort this out. 
 

The switch body is made of a soft type of metal. U can see that on the back side of the switch where the circuit board is mounted the edges of the switch body are folded/bent (there is a better term for this but I forgot it haha) over creating tabs to hold the circuit board in place. My buddy had me pry those out of the way. Two tabs played nicely & I had to take my Dremel to the other two tabs. Then the switch simply pulled apart, we inspected it, all was in good order. We cleaned, lubed with dielectric grease, reassembled, bent the two tabs back into place & created two new tabs with a small tipped screwdriver & small hammer which I had removed with my Dremel 

How did you remove a small hammer from your Dremel? 😎

[kdml]

Thanks.  I’ll pull my switch apart to see what’s going on inside.  Anybody have any thoughts on my first question?

Should I hear a click when applying voltage to the vertical tang on the connector on the side of the transmission?

[arnulfo de l.a.]

9 minutes ago, kdml said:

Thanks.  I’ll pull my switch apart to see what’s going on inside.  Anybody have any thoughts on my first question?

Should I hear a click when applying voltage to the vertical tang on the connector on the side of the transmission?

Yes you should. I hear a click on bothvericle and horizon tang. You don't need to pull your switch apart if working properly in fact I would advise against it.  Use a continuity tester to check it before u take it apart.

[kdml]

Dropped the trans pan this morning and retested by applying 12 volts to each tang on the connector.  Both solenoids are clicking.

I noticed the plug in the inside of the connector seems a little loose. Maybe it wasn’t making good contact.  Or maybe the trans fluid was muffling the noise of the kickdown solenoid.  

Either way things appear to be working and it only cost me some fluid.  

I’ll move on to the switch on the carb next. 

Thanks

[kdml]

Spent some time on the carb switch today.  I pulled it apart, cleaned it and got a better understanding of how it works. 

I don’t believe there was anything wrong with the switch.  I am running and Edelbrock carb and I can’t get enough travel with the linkage to engage the kickdown at WOT and cut power to the micro switch at idle.  I’ve drilled new holes and ovaled out others and just can’t get the right adjustment.

Time to walk away and take a fresh look another day.   

[RivNut]

Ah! The curse of the aftermarket carb. 

 

 

[kdml]

Right

However, all I needed to do was walk away long enough to post my last reply and I figured it out.  The pin the switch mounts to on the carb linkage travels in an arc.  To make the arc wider I actually needed to move the pin up not forward...if that makes any sense.

One new hole and all is working properly. 

 

Thanks 

[telriv]

Glad you worked it out.  I was gonna suggest to replace the throttle shaft for one with the proper hook-ups which I could have done for you.

 

Tom T.

[RivNut]

4 hours ago, kdml said:

Right

However, all I needed to do was walk away long enough to post my last reply and I figured it out.  The pin the switch mounts to on the carb linkage travels in an arc.  To make the arc wider I actually needed to move the pin up not forward...if that makes any sense.

One new hole and all is working properly. 

 

Thanks 

Tonight you'll be dreaming your back in geometry class.  

[RockinRiviDad]

Congrats. I was gonna point u to my EFI thread. I struggled so much with getting my switch to work right that I almost gave up. Like u, I didn’t & it worked out

 

I know it can be a pain in the butt. “BUT” can u post some pix of what u did. I’m sure someone, somewhere is/will be dealing with the same issue. Pix always makes things easier to learn from…well at least for the visual learners like me 😬

[kdml]

The fix was pretty easy in the end. It just took me a while to get there.  

I’m using an Edelbrock throttle lever adapter (part #1418).  It has 2 holes.  One large (top) and one small hole (bottom).  

I first attempted to oval out the bottom hole for more adjustment.  It wouldn’t work as it either provided the right adjustment for kick down or switch pitch, but not both.  

The top hole wasn’t going to work as I couldn’t get WOT before the kickdown switch bottomed out.  

I finally drilled a third hole between the 2 holes.  This worked perfectly.  I adjusted the kick down switch plunger so it lit my test light at or near WOT.  I verified the switch pitch microswitch turned off my test light just off idle. 

 

Doug

[RivNut]

These aftermarket AFB clones can be modified to accept the original carburetor's throttle linkage.  Might be a lot easier.

[XframeFX]

So AFB Clone carbs don't have the same quality casting as Carter carbs and it doesn't accept the original Air Cleaner but, I plunked 1 on a new 350 SBC TargetMaster back in the day and it ran great. 20 MPG on the hwy (imperial gallon).

 

So, can a primary throttle shaft from a switch pitch AFB fit in an Edelbrock AFB Clone? Tom T, Ed?

The other option is to use that 1418 adapter that Doug has pictured.

 

Doug, you no longer have the original Carb? They are usually an AFB and difficult to find nowadays. I like your combo-switch boot, also tough to find.

 

John B.

[telriv]

The AFB & Edelbrocks tops can be changed to accept the smaller diameter air filter housings.

Throttle shafts also interchange..

[kdml]

Unfortunately, my car came originally with a Rochester carb, so I had nothing to interchange with.