When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am switching from a TH350 to a TH400.
Are all vehicles wired for the TH400 kick down regardless of what trans they came with?
If so, what color would that wire be under the dash?
Also, can a kickdown switch be mounted to any gas pedal regardless of what trans was in the car?
Thank you
Yes, the wiring was part of the harness on the 1969-72 cars no matter which trans the car came with. On the 1970-72 cars the kickdown wire harness to the trans was also used on the TH350 for the pressure switch that operated the Transmission Controlled Spark system. ASSUMING (since you didn't tell us) that you have a 69-72 A-body Olds, you will need the correct TH400 accelerator pedal. The extra tab for the TH350 kickdown cable will interfere with the TH400 switch if you try to use the original pedal. The wires under the dash that connect to the switch should have a two-terminal connector with pink and orange wires. The wire to the trans will be black with an orange stripe.
In the first photo, the TH350 pedal is on the right. The other two are TH400.
This is what happens if you try to use the TH350 pedal with the TH400 switch.
I'm in the final stages of a 350 to 455 swap on my 71 Cutlass S.
I bought the pedal switch and bracket aftermarket and ground off?chiseled the tab for the TH350 kick down cable. The wiring for the switch was right there under the dash. My biggest problem was finding the Black/Orange wire to hook to the trans. I found it today when I started restoring my engine bay wiring. It was cut and taped up in the lower section of wiring for the starter. It makes perfect sense for it to be there but for those of us that don't know...... I was looking for a drop around the console where the shifter cable drops from the dual gate shifter.
Now I will have to buy (rubber boot/connector?) as I mentioned the wire was cut at the factory. Hopefully someone will find this info useful.
Last edited by Mkooms; December 29th, 2023 at 05:23 PM.
That wire was not cut from the factory. A 1971, even with TH350, should have the two wire pigtail and connector to the trans. This was used for the transmission controlled spark system. While the kickdown wire wasn't used, the TCS wire was required for the TH350.
Ok, I see what you’re saying and why no one else needed explanation to where the engine bay pigtail was. My uncle ordered this car and sold it to me. He believed in keeping it original, however he did disable the TCS….so at some point he cut the wire and folded it into the harness.
thank you for the info.
September 18th, 2023, 10:05 AM
