L82 ‘75 Corvette
Race Director
Joined: Mar 2017
Posts: 11,805
Likes: 4,422
From: Virginia
The plug at the (not actually a proportioning valve but every one calls it that anyway) switch acts as a ground. If your brake light lights on your dash, that may be why it was disconnected. Please fix the root cause of the issue, not just the symptom. 
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,909
From: Connecticut, USA
The 73-75 L82 vettes had a working cowl door hood, that might be the connector from the switch under the gas pedal. There would be a brown wire going down the hood up to the door. I had an original 75 L82 4 speed coupe but it's been a long time and it's long gone now.
Le Mans Master
Joined: Aug 2006
Posts: 7,411
Likes: 1,549
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
The Brake light switch get only one TAN wire
The Air door connector has two wires TAN & BLACK
The Alarm connector has two wires PINK & ORANGE
'75 schematic:
https://docs.google.com/viewer?a=v&p...WRiNTdjNjdkNTQ
The Air door connector has two wires TAN & BLACK
The Alarm connector has two wires PINK & ORANGE
'75 schematic:
https://docs.google.com/viewer?a=v&p...WRiNTdjNjdkNTQ
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Melting Slicks
Joined: May 2006
Posts: 2,364
Likes: 103
From: Centerville Louisiana
I have a 75 L82 it’s hanging on mine too the alarm is switch is long gone. On another 75 yellow and brown goes below windshield washer reservoir. I’ll try to look it over a little closer tomorrow.
Thread Starter
Intermediate
Joined: Jun 2010
Posts: 29
Likes: 2
From: Cairns Qld Australia
L82 `75 Corvette
100% correct , it is just a pressure differential switch. Simple spool shifts with system pressure loss on one side or the other.
The 73-75 L82 vettes had a working cowl door hood, that might be the connector from the switch under the gas pedal. There would be a brown wire going down the hood up to the door. I had an original 75 L82 4 speed coupe but it's been a long time and it's long gone now.
The 73-75 L82 vettes had a working cowl door hood, that might be the connector from the switch under the gas pedal. There would be a brown wire going down the hood up to the door. I had an original 75 L82 4 speed coupe but it's been a long time and it's long gone now.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
Le Mans Master
Joined: Aug 2006
Posts: 7,411
Likes: 1,549
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
