Cruise Control shuts off
Thread Starter
Pro
Joined: Mar 2006
Posts: 700
Likes: 2
From: Spring Hill Florida
Cruise Control shuts off
Driving on the Veterans (Tampa) Saturday; which has to be the worst road in Florida, I hit a bump and the cruise control shuts off. When I got home I checked the fuse, the vacuum hoses and all controls. Nothing! Any ideas? 1986 Convertible.
Last edited by Pres712; Dec 15, 2015 at 06:17 AM. Reason: adding text
Team Owner
Joined: Jul 2006
Posts: 22,190
Likes: 4,178
From: Kannapolis NC
The brake light switch could need to be adjusted to keep the pedal lever from contacting the switch too soon. Without that cutoff of the cruise, the car would try to accelerate as you're braking. If it's a manual, the same is true for the switch on the clutch that is designed to disengage the cruise when you touch the clutch. If it didn't, when you pressed the clutch, the engine would over rev immediately trying to keep up with the cruise setting. Check to see if either pedal is bouncing against the switches.
Last edited by 65GGvert; Dec 15, 2015 at 06:32 AM.
Thread Starter
Pro
Joined: Mar 2006
Posts: 700
Likes: 2
From: Spring Hill Florida
The brake light switch could need to be adjusted to keep the pedal lever from contacting the switch too soon. Without that cutoff of the cruise, the car would try to accelerate as you're braking. If it's a manual, the same is true for the switch on the clutch that is designed to disengage the cruise when you touch the clutch. If it didn't, when you pressed the clutch, the engine would over rev immediately trying to keep up with the cruise setting. Check to see if either pedal is bouncing against the switches.
You are right. Automatic tranny. Thanks...
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
if thats not it might be your vacumme line right by the firewall.mine would hold vacumme when tested because it would colapse there. it was like a dead nightcrawler there. found a easy way to replace it. just reach up under the dash and cut it. then cut the hose in half about three inch. then el tape some bailing wire in it as far as you can. then lube the hose. then revers to install. and put a connector on it.
Last edited by antfarmer2; Dec 15, 2015 at 08:41 AM.
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
Switch @ the brake pedal first and also with an older/high miler you might want to confirm there's little or no wobble of the brake pedal in either direction (side to side OR excessive up/down). Reach down by hand and see if you can lift the pedal towards you at all. Reseat the switch and try again.
The vacuum release and cruise release is a separate switch for the earlier C4. You should have a pair. Look for one with both a vacuum fitting on the end and electrical terminals.
GM # 1645516 should get you GOOGLE images as to what to look for and maybe use that number as a reference at your local AP store for a replacement. Should be cheap.
The vacuum release and cruise release is a separate switch for the earlier C4. You should have a pair. Look for one with both a vacuum fitting on the end and electrical terminals.
GM # 1645516 should get you GOOGLE images as to what to look for and maybe use that number as a reference at your local AP store for a replacement. Should be cheap.
Last edited by WVZR-1; Dec 15, 2015 at 11:27 AM.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Switch @ the brake pedal first and also with an older/high miler you might want to confirm there's little or no wobble of the brake pedal in either direction (side to side OR excessive up/down). Reach down by hand and see if you can lift the pedal towards you at all. Reseat the switch and try again.
The vacuum release and cruise release is a separate switch for the earlier C4. You should have a pair. Look for one with both a vacuum fitting on the end and electrical terminals.
GM # 1645516 should get you GOOGLE images as to what to look for and maybe use that number as a reference at your local AP store for a replacement. Should be cheap.
The vacuum release and cruise release is a separate switch for the earlier C4. You should have a pair. Look for one with both a vacuum fitting on the end and electrical terminals.
GM # 1645516 should get you GOOGLE images as to what to look for and maybe use that number as a reference at your local AP store for a replacement. Should be cheap.
In addition, on the later cars like my 94 which uses a different cut off switch the contacts of the switch get dirty and develops high resistance in the switch. Causes all sorts of strange problems like no engage, drops out, speed changes lower.
In my case I was able to disassemble the switch and clean it instead of replacing the switch. Don’t know if yours offers the same option. The repair was easy compared to finding the problem 10 years ago.
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
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
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Did you check the main on-off switch?
Is it totally dead now where it won't engage at all?
Might me time to grab a meter and make some initial measurements which a schematic would be a great help.
Is it totally dead now where it won't engage at all?
Might me time to grab a meter and make some initial measurements which a schematic would be a great help.
Team Owner
Joined: Jul 2006
Posts: 22,190
Likes: 4,178
From: Kannapolis NC
When you replaced the switch, did you verify that the contacts were opening when pedal pressed and closing when pedal at rest? It's adjustable. Nothing else will work until you get that. With the pedal not pressed, you should only have voltage on one side of that switch. Are your brake lights flickering when you wiggle the pedal up and down a little?
