Another 700 r4 question.
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,360
Likes: 59
From: Meldrim Georgia
Another 700 r4 question.
I'm going to try to finish up installing my 700r4 in 1980 this weekend. I'm installing a B&M locked up kit. The kit number kit is 70244. It is the mechanical one that works of the speedometer. This is were im confused about the yellow wire that hooks to the brake pedal. My car has cruise control. I've done searches and in some of those searches it says I need a 4 pin brake switch. Is that correct or can I use the one I have. If so how do I hook it up?
Last edited by havesometo; Feb 14, 2014 at 11:49 PM.
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,573
Likes: 7,015
From: New Or-leens Loo-z-anna
To keep things simple for now.....the yellow wire can go from the control box to the transmission connector so you can drive the vehicle without spending hours rewiring a new 4-pin switch into place.
(If the engine tries to stall during sudden stops, the yellow wire can be cut and routed through the brake switch---provided it is the correct style switch)
The thing to remember is---the section of yellow wire that goes from the brake light switch to the transmission connector should lose power when the brake pedal is depressed---and should regain power when the brake pedal is released-----the brake light switch should act like an emergency power cut-off when the pedal is depressed).
If the brake light switch is not capable of doing the above described actions, you may need a 4-terminal switch....1 pair of terminals to activate the brake lights-------and the other pair of terminals to temporarily interrupt power to the yellow wire that goes from the switch to the transmission when the pedal is depressed.
(If the engine tries to stall during sudden stops, the yellow wire can be cut and routed through the brake switch---provided it is the correct style switch)
The thing to remember is---the section of yellow wire that goes from the brake light switch to the transmission connector should lose power when the brake pedal is depressed---and should regain power when the brake pedal is released-----the brake light switch should act like an emergency power cut-off when the pedal is depressed).
If the brake light switch is not capable of doing the above described actions, you may need a 4-terminal switch....1 pair of terminals to activate the brake lights-------and the other pair of terminals to temporarily interrupt power to the yellow wire that goes from the switch to the transmission when the pedal is depressed.
Last edited by doorgunner; Feb 15, 2014 at 03:17 AM.
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Your 1980 has lock up already in it , It is vacuum controlled and located on the firewall just to the right of the break booster.It has a green wire that is used for the lock up and it is wired into the breaks already.
What i did was put a toggle switch in line with that green wire and a 4th gear pressure switch inside the valve body . This was cheap and fool proof.
What i did was put a toggle switch in line with that green wire and a 4th gear pressure switch inside the valve body . This was cheap and fool proof.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Your brake pedal switch should already have a set of NC contacts for the brake lights and a NO set for the lockup and cruise control.
If you find that it does not, you can buy a brake light switch for an S-10 pickup with cruise control at the auto parts store, and just replace the switch you have.
Remember that the 'normal' position of that switch/pedal is NOT depressed has the plunger "engaged". When you depress the pedal, it releases the switch; so the contacts actuate in reversed action.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Just be AWARE that I bought a 4 pin brake light sw for my '72, and the stupid normally closed contact set would open up when the switch got HOT, and so the converter would unlock, press on the brake pedal and it would allow lockup for a little while.....same thing, opens up and no lockup....drove me krazy for a while.....it was a popular brand too.....I'd trust none of them.....
stick a relay in there to open some contacts when actuated by brake light power.....that will release the 12 volts to the converter......
stick a relay in there to open some contacts when actuated by brake light power.....that will release the 12 volts to the converter......
Melting Slicks
Joined: Dec 2009
Posts: 3,225
Likes: 654
From: Thunder Bay
I wired mine to the existing cruise control switch on the brake pedal on my '79. Worked perfectly for years. Just remember it should supply power when the pedal is released, and cut power when the brake pedal is depressed.
I also installed a vacuum controlled switch which would cut power to the lockup if the engine quit (and vacuum dropped off).
I also installed a vacuum controlled switch which would cut power to the lockup if the engine quit (and vacuum dropped off).
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,573
Likes: 7,015
From: New Or-leens Loo-z-anna
