97 seville no cluster or courtesy lights & light switch lights & courtesy only come on when dome light switch is on

If the dome lights in your 2009 Cadillac CTS are not turning off, it can be a frustrating issue. Here are some steps to diagnose and potentially fix the problem:
1. **Manually Turn Off the Dome Lights:**
- In most vehicles, including the Cadillac CTS, there's typically a manual switch on or near the dome light itself. Ensure this switch is in the "Off" position.
2. **Check for Open Doors:**
- Make sure all doors, including the trunk and the hood, are completely closed. Sometimes, a door ajar can prevent the dome lights from turning off.
3. **Interior Light Dimmer Control:**
- Check the position of the interior light dimmer control, which is usually located on the headlight switch or dashboard. If it's turned all the way up, it may keep the dome lights on. Adjust it to the lowest setting.
4. **Ignition Switch:**
- Ensure the ignition switch is in the "Off" position. Sometimes, if the ignition switch is left in the "Accessory" position, the dome lights may stay on.
5. **Faulty Door Switches:**
- Each door usually has a door switch that signals the lights to turn on when a door is opened and off when it's closed. One of these switches may be malfunctioning. You can try manually pressing and releasing each door switch to see if the lights respond.
6. **Battery Disconnect and Reconnect:**
- If the above steps don't work, you can disconnect the vehicle's battery for a few minutes and then reconnect it. This can sometimes reset the electrical system and resolve the issue.
7. **Consult the Owner's Manual:**
- Refer to your Cadillac CTS owner's manual for specific information about the dome light controls and troubleshooting tips.
8. **Professional Diagnosis:**
- If the issue persists, it may be related to a more complex electrical problem. In this case, it's advisable to consult a professional mechanic or an auto-electrician to diagnose and repair the problem.
It's important to be patient and methodical when troubleshooting this issue, as it can have various causes. If you're not comfortable working on the electrical system of your vehicle, seeking professional help is a wise choice to avoid further complications.

Check fuses under the hood on driver side

The dome lamp switch has 3 positions: DOOR, OFF, and ON. When in the DOOR position, the dome lamp operation is controlled by the body control module (BCM).The ON position provides a ground for continuous operation. Ground is provided at G302. The OFF position turns OFF any dome lamp operation. The courtesy lamps, may be manually turned ON by placing the instrument panel (I/P) dimmer switch in the DOME position. When the dome lamp switch is in the DOOR position, the dome lamp will illuminate when a door is opened. When a door is opened, the courtesy lamps turn ON. After all the doors have been closed, the courtesy lamps will remain illuminated approximately 10 seconds after the last door closes. When the driver places the dome lamp switch in the OFF position, the dome lamp will be disabled.

Do you hear any chimes when the light comes on ? Door ajar switch problem , maybe . Picture of car with door open light lit on the instrument cluster ? When does it come on , when driving or sitting still or both ?

You mite want to take it to a qualified repair shop and have it checked for DTC'S - diagnostic trouble codes .
DTC B2555 05: Passenger Compartment Lamp Control Circuit Short to Battery or Open
The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamps high control circuit. When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch open input, the BCM will activate the courtesy lamp high control circuit, providing battery voltage to all of the dome lamps, reading lamps, rear compartment lamp, and vanity mirror lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the courtesy lamp high control circuit to prevent a total battery discharge condition.

Do you know how to do basic automotive electrical testing ? How to test inputs and outputs of a control module ? in this case the BCM - body control module ? Find wiring diagrams at
http://www.bbbind.com/free_tsb.html also watch this video ECM Inputs and Outputs Diagnosis

The following lamps may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door while the switch is in the AUTO position.
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The dome lamp

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The liftgate lamps

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Courtesy/map lights

The courtesy lamp supply voltage circuit of the body control module (BCM) supplies battery positive voltage to the dome lamp, the liftgate lamps, and the map lamps. When any door is opened, the door jamb switch contacts close providing a door open input to the BCM. The BCM then provides a ground to the interior lamps with the switch in the AUTO position. The interior lamps receive a ground at G401 with the switch in the ON position.
Important: If the liftgate is opened after all the modules go to sleep, the dome light will not come on. The liftgate ajar switch input to the BCM will not wake up the BCM once it has gone to sleep, so the dome light will not come on. Once the BCM gets an input to wake it up, from remote keyless entry (RKE) or a door handle, the dome light will turn on when the liftgate is opened.
If the driver inadvertently leaves any interior lamp ON, the BCM will turn it OFF after a 20 minute time-out.
The courtesy lamps will turn OFF immediately if the ignition switch is turned to the ON position or approximately 20 seconds after all doors are closed.
The courtesy lamps are controlled by the body control module (BCM). Inputs from the dome lamp switch and the door ajar switches are monitored by the BCM. When a door ajar switch is closed, or the dome lamp switch is turned to the ON position, the BCM supplies the B+ for the courtesy lamps.
With out a factory Tech2 scan tool or equivalent an knowing how these systems work ,you best bet is to take your vehicle to the dealer or some other ASE certified repair shop !

You mite have a DTC - diagnostic trouble code stored in the BCM - body control module , The BCM controls the interior lights ! Have you heard of a BCM ?
DTC B2615
The body control module (BCM) receives a ground signal from the door jamb, liftglass/liftgate, or courtesy lamp switches requesting courtesy/dome lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the courtesy/dome lamps.
Conditions for Setting the DTC
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When the BCM receives a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground.

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When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to voltage or open only to the first splice from the BCM.

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There is a loss of the rear fuse block TBC 3 battery supply voltage to the BCM for more than 1 second

Diagnostic Aids
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Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

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Only an open circuit up to the first splice from the BCM will set DTC B2615.

DTC B3801
The body control module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. When the BCM senses that the courtesy lamp switch signal circuit is grounded when the switch is activated, the BCM will directly illuminate the courtesy/dome lamps. Do you know what a scan tool is ? not a code reader !
Courtesy Lamps Inoperative




GM Tech 2 Training video 1996

Check and see if the lights come on with the passenger door, if so you have a defective courtesy light switch inside the door.

There is no fuse marked for dome light's in the rear fuse box. The BCM - body control module controls the dome / courtesy light's .
The body control module (BCM) monitors the courtesy lamp switch signal circuit in order to determine when the courtesy/dome lamps should be illuminated. When the BCM senses that the courtesy lamp switch signal circuit is grounded when the switch is activated, the BCM will directly illuminate the courtesy/dome lamps.
DTC B3801 Passenger Compartment Lamp Request Circuit

You should possibly think about taking your vehicle to a qualified repair shop !
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With a scan tool, observe the courtesy lamp switch parameter in the body control module (BCM) data list.
Does the scan tool display INACTIVE?
YES - Go to Step 3
NO - Go to Step 4
3
Activate the courtesy lamp switch.
With the scan tool, observe the courtesy lamp switch data parameter.
Does the courtesy lamp switch data parameter change state?

• Test the courtesy lamp switch for sticking in the ON position.
• Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Does the van have remote keyless entry (RKE) system ?
Interior Lighting System Description
Vehicles with the optional remote keyless entry (RKE) system have interior lighting controlled by the body control module (BCM).
This vehicle uses a delayed interior lighting system.
The system functions as follows:
• The dome lamps will illuminate when any door is opened.
• The dome lamps will remain on for 20 seconds after the last door is closed.
• The delay is canceled and the dome lamps will go out when the ignition switch is turned to the ON position.
• The illuminated entry function will not operate when the dome lamp defeat switch is in the OFF position.
• The interior lighting system is protected from battery rundown by the retained accessory power (RAP) system. The RAP system functions by shutting down interior lights after 10 minutes (when ignition is OFF).

Interior Lights Circuit Description
When the interior lamps circuits are closed/enabled, the courtesy lamp relay is activated by the two following coil circuits:
• CKT 690 (GRY/BLK) which is the courtesy lamp enable output of the body control module (BCM) driving the coil side of the relay.
• CKT 1732 (ORN) which is the coil output side of the relay going to the potential grounding switches/sources.
When the courtesy lamp relay is enabled, CKT 156 (WHT) (courtesy lamp output) is enabled by the closed contact at the relay and then grounded by CKT 750 (BLK) at G110.
Some of these circuits can also be activated with the headlamp and panel dimmer switch. When this happens, the coil output side of the inadvertent power relay is grounded to the body control module (BCM) via CKT 1393 (DK BLU)
CKT 40 (ORN) from the courtesy fuse drives both input sides of the inadvertent power relay. When the contact is pulled closed, CKT 1732 (ORN) is supplied power, thus driving any lamps/circuits attached that circuit and providing ground.
The body control module (BCM) also monitors the following four door inputs:
• CKT 49 (DK BLU) -- LH door jamb switch input
• CKT 54 (ORN) -- RH door jamb switch input
• CKT 775 (PNK) -- Side door jamb switch input
• CKT 656 (YEL) -- Rear door jamb switch input/liftgate strut switch input (depending on option content)
When the doors are closed, the body control module (BCM) is in a floating state of 0-2 volts. When the doors are opened, the courtesy lamp relay is activated, sending power to the courtesy lamps.
The headlamp and panel dimmer switch also activates the following interior courtesy lamps when the switch is placed in the PARK or HEADLAMP ON positions:
• RF power window switch
• RH power door lock switch
• LH power window switch
• LH power door lock switch
• LH outside rearview mirror control switch
• Rear radio control head
The dome lamps can be disabled by closing the dome lamp defeat switch located on the headlamp and panel dimmer switch.

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Courtesy or Dome Lamps Inoperative
Step
Action
Value(s)
Yes
No
Important: Verify functional bulbs before beginning diagnostic procedure.
1
Did you perform the Lighting Diagnostic System Check?
--
YES - Go to Step 2
NO - Go to Diagnostic System Check - Lighting Systems
2
Are all of the courtesy/dome lamps inoperative?
--
YES - Go to Step 6
NO - Go to Step 3
3
Activate courtesy/dome lamps
With DMM, check for battery voltage from inoperative lamp CKT 1732 (ORN) to ground
Is battery voltage present?
B+
YES - Go to Step 4
NO - Go to Step 5
4
Repair open in CKT 156 (WHT) between inoperative lamp assemply and S214.
Is the repair complete?
--
NO - Go to Step 10
--
5
Repair open in CKT 1732 (ORN) between inoperative lamp assemply and one of the following splices:
• S258
• S301
Is the repair complete?
--
Go to Step 10
--
6
Turn the courtesy lamp switch to the ON position
Check for battery voltage at BCM C2 cavity B12.
Is battery voltage present?
B+
Go to Step 7
Go to Diagnostic System Check - Body Control System in Body Control Systems
7
Verify continuity of the following three circuits with DMM:
• CKT 1732 (ORN) between courtesy lamp relay and body control module
• CKT 156 (WHT) between courtesy lamp relay and S214
• CKT 750 (BLK) between courtesy lamp relay and S206
Are all of the circuits functional?
--
Go to Step 8
Go to Step 9
8
Replace courtesy lamp relay.
Is repair complete?
--
Go to Step 10
--
9
Repair the inoperative circuit.
Is the repair complete?
--
Go to Step 10
--
10
Operate the system in order to verify the repair.
Did you correct the condition?
--
System OK
Go to Step 2

One of your door sensors (or trunk sensor) is signaling that it is open or the dimmer switch is turned all the way up, which turns on the dome and foot lamps. Try turning the dimmer switch all the way down. If this does not fix the problem you will have to get all the door sensors (and trunk sensor) tested to determine which one needs to be replaced.

Don't think you have a door ajar switch problem , more then like the lighting control module is the culprit . Does the door ajar light on the instrument cluster stay lit ?
The interior lighting can be separated into two distinct modes of operation: the courtesy lighting and the demand lighting. The lighting control module (LCM) controls all of the interior lighting in the vehicle, as described in the following text.
The front dome lamps, rear reading lamps, and instrument panel courtesy lamps, can be illuminated either by opening any of the vehicle doors (courtesy lamp function) or by depressing the headlamp switch (demand lamp function).
When any door is open, the door ajar switch grounds an input to the LCM which then sends power to the courtesy lamps. The voltage sent to the courtesy lamps gradually increases from 0 volts to 12 volts within 500 ms (± 50 ms), to achieve the theater lighting effect. When the door(s) are closed the door ajar switch(es) break(s) the ground to the LCM input which then gradually reduces the power from 12 volts to 0 volts within 5 seconds. (± .5 second).
When the headlamp switch is depressed it grounds an input to the LCM which in turn sends 12 volts to the front dome lamps, rear reading lamps, and instrument panel courtesy lamps. When the headlamp switch is depressed a second time, it breaks the ground to the LCM input which then ceases to send power to the front dome lamps, rear reading lamps, and instrument panel courtesy lamps.

The battery saver will disrupt power to the courtesy lamps after 10 minutes, the demand lamps after 30 minutes, and the headlamps after 10 minutes. Turning the ignition switch to the RUN or ACC position will terminate the battery saver feature by disabling the interrupt timers and reinstate power to the lamps.
Do you know what DTC'S are ? diagnostic trouble codes !
LCM Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1322 Driver Door Ajar Circuit Short to Ground LCM Go To Pinpoint Test F . B1442 Door Handle Switch Circuit Failure LCM Go To Pinpoint Test G . B1445 Door Handle Switch Circuit Short to Ground LCM Go To Pinpoint Test G . B1563 Door Ajar Circuit Failure LCM Go To Pinpoint Test C . B1566 Door Ajar Circuit Short to Ground LCM Go To Pinpoint Test H . B1685 Lamp Dome Input Circuit Failure LCM Go To Pinpoint Test I . B1687 Lamp Dome Input Circuit Short to Battery LCM Go To Pinpoint Test I . - All Other DTCs LCM REFER to Section 419-10 .

PINPOINT TEST C: THE COURTESY LAMPS STAY ON CONTINUOUSLY CONDITIONS DETAILS/RESULTS/ACTIONS C1 CHECK THE SYSTEM OPERATION Open and close each door, making sure that each door is completely closed.

• Are the courtesy lamps still illuminated after the 25 second time-out period?

Yes GO to C2 .

No The system is operating correctly. C2 TEST DOME LAMP SWITCH Depress the dome lamp switch.

• Are the courtesy lamps still illuminated?

Yes DEPRESS the dome lamp switch a second time. GO to C3 .

No The system is operating correctly. C3 CHECK THE LIGHTING CONTROL MODULE
LCM C2145a

• Are the courtesy lamps still illuminated?

Yes REPAIR circuit 53 (BK/LB). REPEAT the self-test. CLEAR the DTCs.

No INSTALL a new LCM. REFER to Section 419-10 . REPEAT the self-test. CLEAR the DTCs.