Help needed - New dash harness, won't start
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
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From: Kanata ON
Help needed - New dash harness, won't start
I installed a new dash harness this winter (my old one was a mess of electrical tape, mystery wires and even a marette).
I test fired the vette and no dice.
Here's what I have done so far:
Attempt to start car, starter doesn't roll over.
With key on, I get the seat belt buzzer from behind dash.
If I have seatbelt on or off, car doesn't start.
Tried to start the car standing up, doesn't start
I don't have a bypass relay (am I supposed to?)
Horn works
Turn key on, dash lights up (hand brake light for example)
With key on, 12v to the C connection of the bypass relay, starter works.
D does not have constant 12v.
Where do I go from here?
I test fired the vette and no dice.
Here's what I have done so far:
Attempt to start car, starter doesn't roll over.
With key on, I get the seat belt buzzer from behind dash.
If I have seatbelt on or off, car doesn't start.
Tried to start the car standing up, doesn't start
I don't have a bypass relay (am I supposed to?)
Horn works
Turn key on, dash lights up (hand brake light for example)
With key on, 12v to the C connection of the bypass relay, starter works.
D does not have constant 12v.
Where do I go from here?
Le Mans Master
Joined: Aug 2006
Posts: 7,425
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
74 has a 1 year only seat belt interlock system, slide the seats forward and disconnect under the seats to eliminate that problem.
Next check the 'Starter safety switch' on the clutch pedal, purple/white is hot with the key in 'START', purple brings power to the 'S' terminal on the starter.
Next check the 'Starter safety switch' on the clutch pedal, purple/white is hot with the key in 'START', purple brings power to the 'S' terminal on the starter.
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
Unplugged the drivers seat, the passenger side was already unplugged.
No change, buzzer still sounds, car doesn't turn over
I will check the starter clutch switch next.
No change, buzzer still sounds, car doesn't turn over
I will check the starter clutch switch next.
Last edited by moonsteel; Mar 21, 2010 at 08:59 PM.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Pete,
I don't remember for sure.. and you would know more than me.. but don't you have to wire around the firewall relay to get the over-ride out of the system.
Willcox
I don't remember for sure.. and you would know more than me.. but don't you have to wire around the firewall relay to get the over-ride out of the system.
Willcox
Le Mans Master
Joined: Aug 2006
Posts: 7,425
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Pretty sure either way takes the relay out of the system.
I just disconnected under the seats.
If you want to bypass the relay heres how.
I just disconnected under the seats.
If you want to bypass the relay heres how.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
From memory I remember the override relay connector have 4 terminals.
Looking at the wires coming to the connector you need to jumper the green with black tracer to the purple.
The green/black will have 12v "when the key is in the "start" position.
The purple goes down to the S term of solenoid.
(Side note-the relay we are talking about now is the starter override relay,,you can also jumper inside the car at the interlock relay.)
Looking at the wires coming to the connector you need to jumper the green with black tracer to the purple.
The green/black will have 12v "when the key is in the "start" position.
The purple goes down to the S term of solenoid.
(Side note-the relay we are talking about now is the starter override relay,,you can also jumper inside the car at the interlock relay.)
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
I was following the diagnosis steps from the repair manual. For some reason I thought C (jump here) had 12 volts constant, not just when I have the ignition to start.
I'll check tonight to see if I'm getting 12v when starting.
I'll check tonight to see if I'm getting 12v when starting.
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Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
Le Mans Master
Joined: Aug 2006
Posts: 7,425
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Thread Starter
Holley HP EFI w/TPI
Joined: May 2009
Posts: 553
Likes: 0
From: Kanata ON
From memory I remember the override relay connector have 4 terminals.
Looking at the wires coming to the connector you need to jumper the green with black tracer to the purple.
The green/black will have 12v "when the key is in the "start" position.
The purple goes down to the S term of solenoid.
(Side note-the relay we are talking about now is the starter override relay,,you can also jumper inside the car at the interlock relay.)
Looking at the wires coming to the connector you need to jumper the green with black tracer to the purple.
The green/black will have 12v "when the key is in the "start" position.
The purple goes down to the S term of solenoid.
(Side note-the relay we are talking about now is the starter override relay,,you can also jumper inside the car at the interlock relay.)
Stuck my head under the dash, noticed that my clutch interlock wasn't plugged in, jumpered it, car fired up.
Now one more Q.
The prong I jumpered was in a T, but the clutch looks like it's two prongs beside each other. Am I missing a piece of my harness?