TH400 Kickdown Issues
Thread Starter
Cruising
Joined: Dec 2004
Posts: 10
Likes: 0
TH400 Kickdown Issues
I'm new to this forum, although I recognize a lot of names here from the others. The reason I bring up this question is that I've noticed a lot of people here have dealt with TH400 issues.
My question is, my kickdown does not work at all. I removed and tested my switch, it's fine. However, I am not getting any voltage on the harness that plugs into the switch. Could someone tell me where those wires trace to? It's awfully hard to tell in the assembly manual. Thanks ahead of time!!
Vince
By the way, my Vette's a 1970 Coupe, LS5.
My question is, my kickdown does not work at all. I removed and tested my switch, it's fine. However, I am not getting any voltage on the harness that plugs into the switch. Could someone tell me where those wires trace to? It's awfully hard to tell in the assembly manual. Thanks ahead of time!!
Vince
By the way, my Vette's a 1970 Coupe, LS5.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
I had the same issues on my '69.. My mechanic at that time told me that the kickdown of the TH400 is electric and inside the tranny, unlike the TH350 and TH200R4 which have a mechanical cable that triggers the kickdown.. As I understand it - the transmission would have to be taken apart to fix the kickdown...
Safety Car
Joined: Jul 2002
Posts: 4,269
Likes: 3
From: St. Charles IL
Cruise-In 5-6-7-8-9-11-12 Veteran
A CI-6 Car Show Winner
The schematic for my 75 shows a 25 amp inline fuse up in the dash somewhere, connected to a tan wire #141. Goes from there to the ignition switch. You should probably get one of those laminated diagrams from Lectric Limited or other suppliers, your year might be different.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Going from memory, but I thought the switch had a pink 12v ignition switched wire to supply it and a tan (or maybe orange) wire from there to the transmission. Is there a pink wire that plugs into the fuse box? Probably you have a bad accessory fuse or the wire has come unplugged.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by Vinn
By the way, my Vette's a 1970 Coupe, LS5.[/SIZE][/FONT][/B]
The previous owner of my 75 had the solenoid that is located in the
tranny replaced. It's not that bad - my recollection is that it
is accessible from just dropping the pan.
Hope it's just a fuse ...
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Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
I have a 69, 70, and 71 Service Manual. I don't see any reference to the wire colors. It works as follows: 12v ignition switched to the switch on the accelerator pedal. From the other side of the switch to the pin on the side of the transmission. When you get full throttle or close you get 12v to the trans. Sounds like the wiring from switch to trans is there, just find 12v switched to the other side of the switch and it should work. Make sure all your fusesare good first though.
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
I just checked my 73 schematic, it shows a tan wire out of the fuse block that splits to the switch and the firewall connector. A yellow wire goes from there to the radio. The fuse is labeled TCS SOL RDO and also feeds the spare ACC terminal in the fuse block. Joe
Thread Starter
Cruising
Joined: Dec 2004
Posts: 10
Likes: 0
Well I just bought a Lectric Limited wiring diagram. It looks like the one for '70 doesn't have the kickdown on it. I'll try to go off of what was posted here and trace it out myself tomorrow. It's tricky because the wires from the switch go through a hole in the firewall and get lost in the rest of the engine compartment. I guess I'll find the problem eventually!
Vince
Vince
