74 won't start please help
Thread Starter
8th Gear
Joined: Jan 2011
Posts: 8
Likes: 0
From: West Milford NJ
74 won't start please help
Hi,
I am new to this site and to owning a vette, I have a 74 vette, 4 speed, AC, tilt, power windows and factory alarm.
When I turn the key to start the car there is a buzzer sound behind the center top area of the dash and engine crank, I checked battery and voltage is good. I looked in my shop manual at the wiring digram and got lost.
Any ideas would be helpfull.
I am new to this site and to owning a vette, I have a 74 vette, 4 speed, AC, tilt, power windows and factory alarm.
When I turn the key to start the car there is a buzzer sound behind the center top area of the dash and engine crank, I checked battery and voltage is good. I looked in my shop manual at the wiring digram and got lost.
Any ideas would be helpfull.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
The buzzer is the seat belt reminder. 74s have sensors which detect 40 or more pounds on the seat bottom, then reminds you to buckle the belts. The owner's manual tells you how to reset the interlock switch under the hood when needed. Ed T's pic.
My 74 would sometimes fail to start. Resetting the interlock switch worked on those occasions.
My 74 would sometimes fail to start. Resetting the interlock switch worked on those occasions.
Last edited by Easy Mike; Jan 15, 2011 at 11:26 AM.
Thread Starter
8th Gear
Joined: Jan 2011
Posts: 8
Likes: 0
From: West Milford NJ
Buckled the belt and tried starting, no good. Removed the relay under the hood, cleaned the contacts and tried again. Started right up. Thanks guys.
Now I just need to figure out why the new battery drains down after about two weeks.
Now I just need to figure out why the new battery drains down after about two weeks.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
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Race Director
Joined: Mar 2006
Posts: 14,112
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From: Florida
Don't know what you mean by "one time"
I just remove the orange mount, solder the green and purple connectors together and reinstall the orange mount. Can't tell it's been bypassed.
Race Director
Joined: May 2006
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From: Dayton, Ohio
This relay (the one on the firewall) is very very seldom ever used and on some cars never gets used at all. This relay is the "bypass" relay not the "seat belt interlock" relay that gets used "every" time you start the car.
Yes both relays have the green and purple but both relays have very different functions.
You can bypass at either one though.
My comment [ "doesn't make sense why cleaning the contacts would help" ] was because you can remove the firewall relay and if the interlock relay under the console is working the car will start like normal. If the relay in the console goes bad , you have to push the button on the firewall relay "every" time you start the car.
In general most people don't really understand how the system is wired.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
"One time" meaning you get 1 start every time you push the button,providing the ign key is in the ON position.
This relay (the one on the firewall) is very very seldom ever used and on some cars never gets used at all. This relay is the "bypass" relay not the "seat belt interlock" relay that gets used "every" time you start the car.
Yes both relays have the green and purple but both relays have very different functions.
You can bypass at either one though.
My comment [ "doesn't make sense why cleaning the contacts would help" ] was because you can remove the firewall relay and if the interlock relay under the console is working the car will start like normal. If the relay in the console goes bad , you have to push the button on the firewall relay "every" time you start the car.
In general most people don't really understand how the system is wired.
This relay (the one on the firewall) is very very seldom ever used and on some cars never gets used at all. This relay is the "bypass" relay not the "seat belt interlock" relay that gets used "every" time you start the car.
Yes both relays have the green and purple but both relays have very different functions.
You can bypass at either one though.
My comment [ "doesn't make sense why cleaning the contacts would help" ] was because you can remove the firewall relay and if the interlock relay under the console is working the car will start like normal. If the relay in the console goes bad , you have to push the button on the firewall relay "every" time you start the car.
In general most people don't really understand how the system is wired.
Frankly, I've never rung one of these out, always eliminated them, but just removing the relay will leave the purple and green permanently disconnected.
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
It may just be poor communication and understanding here, but I assumed that this relay (orange) has to engage to start every time and the button was just the manual overide that latched the coil so the green and purple had continuity to start the car.
Frankly, I've never rung one of these out, always eliminated them, but just removing the relay will leave the purple and green permanently disconnected.
Frankly, I've never rung one of these out, always eliminated them, but just removing the relay will leave the purple and green permanently disconnected.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I think (because I'm no relay expert) what you'll find is the pink in the console relay will tick the relay and connect the green and purple but in the orange relay the pink is hot to the relay but is only there to hold in the relay after the manual button is pushed.
EDIT- correction-I was wrong,the pink is hot with the key on in both relays. The small dk green is what should tick the console relay , the orange relay is still ticked manually by the button.
Last edited by ...Roger...; Jan 16, 2011 at 08:24 AM.
Platinum Supporting Vendor
Joined: Sep 2001
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My restored 74 decided to this for the very first time when I selling it and went to start it for the man looking at it. Before that it always worked fine. You have to hit the interlock relay button under the hood, she will start for you after that.