All interior lights stay on but slightly different than others with same problem NEED HELP PLEASE

[empire5150]

Hello, I just bought a nightmare. UHMM I mean a Corvette. 1984 coupe. Its my first and I have a problem with the interior lights. They stay on all the time but at a dim amount. When I twist the headlight knob to turn on the interior lights they all brighten to the regular amount, then when you twist to turn the interior lights off they all stay on but dim. So far I took the 2 jam pin switches out and unplugged them and all the lights still stay on. If the switch(s) were bad wouldn't unplugging them shut off the lights? Also, I noticed that the drivers switch has 3 little pins for contact and the passenger side switch has only 2 pins. Is this correct or did I have a wire/pin lead fall out of the connector and is laying inside the jam? Also when I put a test light on the individual pins 2 of the 3 on the driver side had power and 1 did not. On the passenger side both pins had power. Is this correct? I noticed the 15 amp acc fuse was blown before I started the diagnosis and I replaced it first. It is still working and not blown at the moment. Any help would be greatly appreciated!! Thanks in advance...

 

[vetteoz]

When I twist the headlight knob to turn on the interior lights they all brighten , then when you twist to turn the interior lights off they all stay on but dim.

Would indicate the rheostat part of the headlight switch that works the interior lights is broken so the dimmer does not go to the fully off position.

 

[empire5150]

Would indicate the rheostat part of the headlight switch that works the interior lights is broken so the dimmer does not go to the fully off position.

Thank you for the help. Is there 2 switches, 1 for the headlights and 1 separate one for the dimmer? If so, which are you speaking of? Can you tell me where the switch is located in the car?

 

[ecss]

There are 3 ways to turn on the interior courtesy lights.
Use the headlight switch. All interior courtesy lights come on
Open one of the doors. All interior courtesy lights come on.
Open the rear hatch. If the doors are closed and the rear hatch is open, only
the two cargo lights on the B pillar should light.

When the doors or hatch are open, the Courtesy Delay Timer module grounds
the courtesy lights when it sees one of the door pin switches closed (door open).

When you use the headlight switch to turn on the courtesy lamps, the headlight
switch provides the ground for the courtesy lamp bulbs.

The schematic shows the current path in Blue when the headlight switch is used.
The Red shows the current path when the Courtesy Lamp Delay Timer controls
the ground path when a door is opened.

In your case something is providing a ground path and turning the interior courtesy
lights on. Because the lights are dim, the path to ground has some resistance.

Most likely the Delay Module is bad.

Here's a picture of what it looks like. If you unplug it and the lights are no longer on
the module is bad. If the lights are still on and dim disconnect the headlight switch.
If they are still on, there is a wiring problem.

The delay module is taped to a wire harness under the passenger side of the dash.
You may need to unplug some wiring connectors that run under the ECM. Remove two nuts from the bracket that holds the ECM in place. Drop the ECM (computer) down and look up in that area for the delay module.

Your question about the 3 pins on the drivers A pillar switch.
1 pin is for the chime module when the door is open and key is in ignition.
1 pin goes to the Courtesy Delay Timer module.
1 pin goes to the Alarm module.

The passenger side switch does not have a pin for the chime module so there
are only two pins.

Below is a picture of the Delay Module and the schematics showing the courtesy lamps.

 

[vetteoz]

Most likely the Delay Module is bad.
If you unplug it and the lights are no longer on the module is bad. If the lights are still on and dim disconnect the headlight switch.
If they are still on, there is a wiring problem.

you can bypass the Delay timer if it is bad.
At the timer connector, cut the white wire at Pin A and cut the two white wires at Pin D. Solder the three white wires together.
This will cause the courtesy lights to come on when the doors are opened and go out when the doors are closed with no delay time out

 

[empire5150]

There are 3 ways to turn on the interior courtesy lights.
Use the headlight switch. All interior courtesy lights come on
Open one of the doors. All interior courtesy lights come on.
Open the rear hatch. If the doors are closed and the rear hatch is open, only
the two cargo lights on the B pillar should light.

When the doors or hatch are open, the Courtesy Delay Timer module grounds
the courtesy lights when it sees one of the door pin switches closed (door open).

When you use the headlight switch to turn on the courtesy lamps, the headlight
switch provides the ground for the courtesy lamp bulbs.

The schematic shows the current path in Blue when the headlight switch is used.
The Red shows the current path when the Courtesy Lamp Delay Timer controls
the ground path when a door is opened.

In your case something is providing a ground path and turning the interior courtesy
lights on. Because the lights are dim, the path to ground has some resistance.

Most likely the Delay Module is bad.

Here's a picture of what it looks like. If you unplug it and the lights are no longer on
the module is bad. If the lights are still on and dim disconnect the headlight switch.
If they are still on, there is a wiring problem.

The delay module is taped to a wire harness under the passenger side of the dash.
You may need to unplug some wiring connectors that run under the ECM. Remove two nuts from the bracket that holds the ECM in place. Drop the ECM (computer) down and look up in that area for the delay module.

Your question about the 3 pins on the drivers A pillar switch.
1 pin is for the chime module when the door is open and key is in ignition.
1 pin goes to the Courtesy Delay Timer module.
1 pin goes to the Alarm module.

The passenger side switch does not have a pin for the chime module so there
are only two pins.

Below is a picture of the Delay Module and the schematics showing the courtesy lamps.

Thank you SO MUCH for all the info and for your time. I really appreciate it. Can you answer my question about the pins on the door switches? On the driver side, (When I use my test light) 2 of the 3 pins have power and on the passenger side both pins have power. (This is with the switches unplugged of course) The way I understand all the info you gave me, it does not make sense right? Shouldn't they all be ground so when the pin connects them (door open) it just completes the ground circuit?

 

[empire5150]

you can bypass the Delay timer if it is bad.
At the timer connector, cut the white wire at Pin A and cut the two white wires at Pin D. Solder the three white wires together.
This will cause the courtesy lights to come on when the doors are opened and go out when the doors are closed with no delay time out

Thank you very much for this info. If I cant fix it correctly I will definitely do this. I don't NEED the timer, but I sure would like to have the lights work....

 

[ecss]

on the driver side, (When I use my test light) 2 of the 3 pins have power and on the passenger side both pins have power. (This is with the switches unplugged of course) The way I understand all the info you gave me, it does not make sense right? Shouldn't they all be ground so when the pin connects them (door open) it just completes the ground circuit?

Driver side door A pillar switch has three wires at the pin switch.
Light Green wire is used for the alarm.
Tan wire goes to chime module. (Grounded to sound the chime).
Whiite wire is tied to the other White wire at the passenger side door pin at the Delay module pin D.

When the either door is open, a ground is placed at the Delay module pin D.
This triggers the Delay module to turn the courtesy lights on. It does this by
closing an internal circuit so Pin A and Pin B of the Delay module are connected.
This provides a ground path so the bulbs light.

When the doors are closed, a 30 second time out period begins. After 30 seconds
the Delay timer removes the connection between pin A and Pin B. The ground
path is removed and the lights turn off.

The lights will also turn off immediately after you shut the doors and turn the ignition On. This happens because when you turn the igntion On 12 volts is placed on Pin E
of the Delay module. This is a reset line.

I've never measured the voltages at the door pin switch wires but the switches can't
be the cause of your problem. The White wires are the only wires that have anything to do with the Delay module. They only tell the module to turn the lights on or off. They don't have anything to do with the brightness of the bulbs.

The courtesy lamp circuit is 7 light bulbs in parallel. One side of the bulbs has 12 volts. For the bulbs to turn on a ground path has to be provided. In normal ooperation the ground path is via the Delay module or the headlight switch. You can eliminate them by unplugging them.

The Delay module is a know problem. When it fails it usually keeps the lights on or
off. Your problem is different since the lighs are on dim when they should be off.

I'd unplug the Delay module and see what happens.

 

[empire5150]

Thank you everybody for the help. I have been working on this for a while and gave up and put everything back together last Sunday. When I got your replies to try the timer I went in the garage with high hopes, tore into it again and sure enough, when I unplugged it the lights went out. They seem to function normally now. When I twist the headlight switch they turn on bright and when I twist them off they go off completely. I cant tell if they come on when the doors are open of course because the timers unplugged. I bought a new (used) one online this morning and when it arrives I will plug it in and hopefully everything will be perfect.

I cant thank everyone enough!