buzzer and dome light
Thread Starter
Instructor
Joined: Feb 2025
Posts: 160
Likes: 20
From: Superior WI
buzzer and dome light
I got my 1978 back together again but now it buzzes until I plug in the seat belt and the foot and dome lights never go off. Is it the black box with the buzzer in it that plugs into the fuse box?
Race Director
Joined: Oct 2000
Posts: 12,652
Likes: 3,110
From: Shamong, NJ
To the best of my knowledge the seat belt buzzer and the courtesy light delay timer are two different systems.
It sounds to me that your seat belt buzzer may be working correctly. According to the owners manual if the driver's seat belt has not been buckled before turning the key to either start or run, the buzzer is supposed to sound for 6-8 seconds or until the belt is buckled.
The interior lights are controlled by a timer located to the right of the glove box in the area of the right side dash air vent. The timer is an orange plastic box roughly 2" square that can be identified by the part number "4635989" and the word "TOP" molded into the outside of the plastic case. It's pretty common for the light timers to go bad and they are no longer available, but you can buy a new circuit board to rebuild them. When working properly, after a door is opened the interior lights are supposed to stay on until the key is put in the ignition or for 30 seconds. When the ignition is turned off, the timer leaves the lights on for 15 seconds.
It sounds to me that your seat belt buzzer may be working correctly. According to the owners manual if the driver's seat belt has not been buckled before turning the key to either start or run, the buzzer is supposed to sound for 6-8 seconds or until the belt is buckled.
The interior lights are controlled by a timer located to the right of the glove box in the area of the right side dash air vent. The timer is an orange plastic box roughly 2" square that can be identified by the part number "4635989" and the word "TOP" molded into the outside of the plastic case. It's pretty common for the light timers to go bad and they are no longer available, but you can buy a new circuit board to rebuild them. When working properly, after a door is opened the interior lights are supposed to stay on until the key is put in the ignition or for 30 seconds. When the ignition is turned off, the timer leaves the lights on for 15 seconds.
Thread Starter
Instructor
Joined: Feb 2025
Posts: 160
Likes: 20
From: Superior WI
OK thanks, I did some research on what you talked about. Looks like I'll need to take the glove box out to get to the orange box. I'll jump it by connecting two white wires which will bypass the timer. If it works then it was the orange timer box. If not then I have a short somewhere else. Thanks for the jump start, much appreciated.
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
To the best of my knowledge the seat belt buzzer and the courtesy light delay timer are two different systems (gbvette)
It also occurred to me that the buzzer box has a four-fold function
- Seatbelt warning
- Ignition key in switch but engine off
- Headlamp warning; headlamps on, engine off
- Door ajar
Passenger side courtesy lights were included with RPO ZX2. An electronic circuit provides the timeout feature in an orange box with GM# 4635989 and TOP stamped on the box. On non-air-conditioned cars, the right-hand courtesy light is mounted to the top corner of the right kick panel with a black-oxide hex-head sheet-metal screw. A/C cars have the light mounted under the dash in front of ductwork and heater box. The left light on all cars mounts in a bracket just above the hood-release handle.
Last edited by hunt4cleanair; Nov 4, 2025 at 10:37 AM. Reason: add buzzer four-fold function warning
