1984 Corvette TCC help!
Thread Starter
Navigator
Joined: Sep 2016
Posts: 9
Likes: 0
1984 Corvette TCC help!
I have an 84 corvette that has been acting funny lately. I noticed I didn’t have brake lights, so I took what I thought was the stoplight switch out to replace it. When I went to install the new switch I noticed that the lights still didn’t work. That’s when I discovered that I actually have two separate switches. Then one I had taken out actually controls the TCC and has a vacuum line running to it as well. The vacuum line I believe disengages the cruise control once the brake pedal is applied. Anyway, now I can’t get the torque converter to lock up. If I install the switch (the old one, I returned the one I bought because it was doing the same thing) per the instructions (slide switch all the way in then pull all the way up on the brake pedal) the tranny will shift through second and third very quickly and I will be in 4th at 30 mph with the torque converter locked in. If I take the switch completely out but leave the harness plugged in it shifts great but no torque converter lock up. The transmission is stock. Any ideas? I have searched and searched but it doesn’t seem to be many 84 corvettes with two switches!
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Your shifting questions may be related to your TV (Throttle Valve) cable adjustment. It sounds like you have the FSM, and this adjustment procedure is on pg. 7A-10. This cable adjustment is on your CFI throttle linkage.
The Stop Lamp switch is on pg. 8A-43 (org & wht wires) and the TCC switch is on pg. 8A-28 (pnk/blk & ppl wires)
It's interesting this procedure in the FSM is also covered for the diesel engine option! What's up with that?
Thread Starter
Navigator
Joined: Sep 2016
Posts: 9
Likes: 0
Interesting, I have only been able to find posts that refer to the stoplight switch controlling the TCC and cruise control but not a lot about two switches. Unfortunately I do not have the FSM although I do plan on purchasing one in the future. When the quick shifting problem happened I originally thought that maybe my TV cable was out of adjustment so I did found on here how to adjust it. It shifts firmer then it did before but like I mentioned, with the switch installed the transmission will be in 4th gear by about 30 mph with the torque converter locked up. With the switch just hanging there but still plugged in (plunger on switch completely out) it shifts through the gears perfectly just no TC lock up. I can depress the plunger on the switch while driving and feel the TC lock up. Do you think I need to continue adjusting with the TV cable to get it right or is there possibly another problem in the electronics?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski