1998 mountaineer has no inside lights and instrument panel is dim

Interior Lights Dimming Circuit Description
VF Displays
When the ignition switch is in the RUN position, the instrument cluster activates its VF display. The instrument cluster also coordinates the display illumination for the radio (IRC), the cellular telephone (PHN), and the climate control Panel (CCP) anytime the ignition switch is in the RUN position.
Incandescent Dimming 1 (INC DIM 1)
The INC DIM 1 consists of lamps powered by CKT 8 (GRY). These are referred to as the park lamp backlighting because they are only active if the park lamps are on and the ambient light sensor indicates darkness.
Incandescent Dimming 2 (INC DIM 2)
The INC DIM 2 output is used as a general interior light source and an illuminated entry feature that provides interior lighting. The INC DIM 2 consists of lamps powered by CKT 1244 (BRN). When one or more of the following conditions occur, the INC DIM 2 lamps will be active:
• The interior lamps switch is active.
• The park lamps are on and the ambient light sensor indicates darkness
• The ignition switch is in the RUN position and the ambient light sensor indicates darkness
• A Class 2 message is received from the body control module (PZM) indicating that the courtesy lamps are active.
Dimming
The instrument cluster controls all of the interior dimming functions. The instrument cluster receives an ambient light level input from the ambient light sensor and determines whether it is light or dark. If the ambient light sensor is inoperative, the instrument cluster will assume a condition of darkness. Dimming of the VF displays is only allowed when the ignition switch is in the RUN position, the park lamps are on, and the ambient light sensor indicates darkness. If all conditions for the VF dimming are met, the instrument cluster uses the input from the potentiometer in the headlamp switch to determine the level of dimming. The dimming level is sent to the radio (IRC), the cellular telephone (PHN), and the climate control panel (CCP) via a Class 2 message. These modules then adjust the dimming level of their VF display. The instrument cluster provides dimming control of the incandescent lighting through the INC DIM 1 and INC DIM 2 outputs. The instrument cluster provides dimming control of the electronic PRNDL LED through CKT 1382 (PPL/WHT). The dimming level will very based on the potentiometer in the headlamp switch whenever the parklamps are on and the ambient light sensor indicates darkness, regardless of the position of the ignition switch.


1998 Cadillac DeVille ' DeVille, Eldorado (VIN E/K) Service Manual ' Body and Accessories ' Lighting Systems ' Diagnostic Information and Procedures ' Document ID: 489166
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Interior Lights Dimming System Check
Step
Action
Normal Result(s)
Abnormal Result(s)*
1
Turn the ignition switch to the OFF position.
Place the interior lamps switch in the ON position.
All incandescent lighting on the INC DIM D2 output turns ON. INC DIM 2 includes all of the lighting on CKT 1244 (BRN), which is the backlighting for the headlamp switch and the floodlighting for the vehicle doors.
Incandescent Lamps Inoperative
2
Place the interior lamps switch in the OFF position.
Turn the ignition switch to the RUN position.
INC DIM 2 lighting turns OFF.
All of the VF displays light. VF displays include the following components (if equipped):
• The radio (IRC)
• The cellular telephone (PHN)
• The driver information center (DIC)
• The instrument cluster (IPC)
• The climate control panel (CCP)
• Vacuum Fluorescent Displays Inoperative - All
• Incandescent Lamps Always On
3
Cover the ambient light sensor with the twilight OFF.
Place the headlamp switch in the PARK position.
The park lamps turn ON.
All of the VF displays dim in order to match the current dimming control level. All of the incandescent lighting for INC DIM 1 and INC DIM 2 light at the current dimming control level. INC DIM 1 includes all of the park lamp backlighting on CKT 8 (GRY) which is composed of the following components:
• The radio (IRC)
• The front cigar lighter
• The steering wheel controls
• The driver information center (DIC)
• The climate control panel (CCP)
• The instrument cluster (IPC)
• The heated seat switches
• The auxiliary blower switches
• The ash tray lamps
• The PRNDL lamp
Exterior Lights System Check
4
Rotate the headlamp switch dimming control in both directions.
All of the VF displays and all of the incandescent lighting dim and brighten in response to the headlamp switch dimming control.
Vacuum Fluorescent Displays Do Not Dim with Instrument Panel Dimmer Switch
* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.

Back lighting or warning lights ? check engine , ABS , air bags , seat belt , oil light etc... ?
Interior Lamps Dimming
The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.
• Power window switches
• HVAC control head assembly
• Radio
• The instrument panel cluster (IPC)
When the ignition switch is turned to the ON position, the vacuum fluorescent (VF) display (radio) turns on at maximum brightness. When the park lamps are ON all incandescent back lighting turn ON at the dimming level indicated by the IP dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the park lamp supply voltage circuit provides an input to the body control module (BCM). The BCM then supplies voltage to the instrument panel dimmer switch through the instrument panel dimming lamps control circuit. The setting of the instrument panel dimmer switch determines the amount of voltage that the instrument panel dimmer switch supplies to the BCM through the instrument panel dimming lamps low reference circuit. The BCM then sends a pulse width modulated (PWM) voltage to all the interior lamps. All the vacuum florescent (VF) and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the PARK or HEADLAMP position, all incandescent back lighting turn on at the dimming level indicated by the IP dimmer switch. When the IP dimmer switch is moved from MIN to MAX, all vacuum fluorescent (VF) displays, as well as all incandescent back lighting respond from Minimum intensity to maximum brightness in response to the IP dimmer switch.

I would have it checked for DTC'S - diagnostic trouble codes stored in the BCM !
DTC B2624 Display Dimming Input Range/Performance
The body control module (BCM) supplies voltage to the instrument panel dimmer switch through the instrument panel dimmer switch signal circuit. The dimmer switch varies the voltage and returns the new voltage to the BCM through the dimmer switch signal return circuit. The BCM uses this voltage to determine the illumination level of the instrument panel lamps.

DTC B2625 Display Dimming Pulse Width Modulation (PWM) Output Circuit Range/Performance
The body control module (BCM) receives a variable voltage from the instrument panel (I/P) lamp dimmer switch. The BCM uses this signal in order to vary the illumination level of the I/P lamps. The I/P dimming lamps output from the BCM is a pulse width modulated voltage supply used to light the I/P lamps. If a malfunction occurs in the I/P dimming lamps output circuit, this DTC is set.

DTC B2662 Park Lamp Switch Circuit Malfunction
The park lamps are controlled by the turn/headlamp switch. Positive battery voltage is supplied to the switch through the EXT LP fuse. When the turn/headlamp switch is placed in the park or head position, battery voltage is supplied to the park lamps. The body control module (BCM) is also connected to the park lamp circuit to sense whether or not the park lamps turn ON when the low beam or high beam headlamps are turned ON. The BCM also uses the parklamp battery positive voltage to power the instrument panel (I/P) dimmer output circuit. If the BCM senses that the low beam or high beam headlamps are ON and the park lamp input is not active, DTC B2662 sets.
Do the park lamps work ?

Daytime headlight issue ? No , no sensor behind the front bumper . No Daytime time head lamp issue , doesn't turn on the instrument panel light's . This is more then likely a remote dimmer module problem .
Interior Lights Dimming Circuit Description (Pontiac)
When the park lights are on, battery positive voltage (B+) is applied via CKT 32 (YEL) to the remote dimmer module. The interior dimming switch in the lamp dimmer switch is a variable resistor which applies the dimming input via CKT 44 (DK GRN) to the remote dimmer module. The potentiometer in the lamp dimmer switch cannot provide enough current in order to operate the incandescent lights. The remote dimmer module amplifies the current, applying a variable voltage to the incandescent lights. As the amount of current increases, the lamps become brighter. As the amount of current decreases, the lamps become dimmer.
The radio, heater and A/C control assembly, instrument cluster, and passenger climate control each has a vacuum fluorescent (VF) display. When each module receives an input that the ignition switch is turned to the RUN position, each module activates the VF display at the full intensity. When the park lights are on, the radio receives the dimming level from an input on CKT 8 (GRY). The radio then relays this information to any other modules with VF displays. All modules with VF displays then adjust the dimming level of their VF display in order to match the level of the incandescent lamps.

I'd think maybe a failing rheostat in the instrument panel.


Engine Performance Products

Usually a problem with the mini-lights inside the cluster, the circuit board or the dash light dimmer switch.
You can take the cluster out and see if the bulbs can be replaced or check the dimmer.
Not connected to automatic dimmer headlights.

CHECK THE CLUSTER ELECTRICAL WIRES.COULD HAVE KNOCK THEM LOOSE WHILE REMOVING THE RADIO.

Check the FLASHER, also can review the Fuses, located inside the passenger compartment, under the drivers-side of the instrument panel.

Both the turn signal flasher and the hazard warning flasher are mounted on the fuse panel on the truck. To gain access to the fuse panel, remove the cover from the lower edge of the instrument panel below the steering column. First remove the two fasteners from the lower edge of the cover. Then pull the cover downward until the spring clips disengage from the instrument panel.

The turn signal flasher unit is mounted on the front of the fuse panel, and the hazard warning flasher is mounted on the rear of the fuse panel.




To access the fuses, remove the fuse panel cover. Note the spare fuses (A) and provided fuse puller tool




Fuse panel and power distribution box identification for 1995-99 Explorer/Mountaineer models-Part 1




Fuse panel and power distribution box identification for 1995-99 Explorer/Mountaineer models-Part 2




Fuse panel and power distribution box identification for 1995-99 Explorer/Mountaineer models-Part 3


Power Distribution Box
Located under the hood, in the engine compartment. It houses the fuses and relays for most of the under hood components which are not controlled by a dash mounted switch (such as the alternator, fuel pump, ECM, etc.). The fuses and relays are replaced in the same manner as the fuse panel inside the vehicle. The power distribution box cover is hinged on one end and utilizes a retaining latch on the other. Simply release the latch and lift the cover up to gain access to the fuses and relays.

Hope helped with this; remember rated this help. Good luck.

Soldering the new bulbs in may have done something to the LH DIMMER MODULE ! The 10amp INT LPS fuse located in the I/P fuse box is good ? Is the dimmer switch at full bright ?
When the park lamps are on, battery positive voltage (B+) is supplied through the instrument panel (IP) fuse block INT LPS fuse via CKT 32 (YEL) to the dimming switch. The dimming switch supplies a variably controlled voltage to the dimmer module(s). The potentiometer in the panel dimming control cannot provide enough current in order to operate the panel lamps. The dimmer module(s) amplifies the current, supplying the variable voltage to the panel lights. As the amount of the current increases, the lamps become brighter. As the amount of the current decreases, the lamps become dimmer.
Buick
There is only 1 dimmer module that supplies current to the panel lights. The left dimmer module supplies current via CKT 8 (GRY) to the following components:
• The headlamp switch
• The door switch flood lamps
• The heater and A/C control
• The door handle flood lamps
• The passenger temperature control
• The ashtray lamp
• The shift select switch lamp
• The instrument cluster
• The steering wheel controls
• The reset switch
• The trip odometer
• The radio
Parade Dimming
The parade dimming feature prevents the dimming of the VF displays when daylight is sensed by the lamp control module (LCM) and the park lamps are turned on manually. If the LCM senses night time conditions and the park lamps are on, the LCM allows the VF displays to be dimmed.
All of the modules with the VF displays receive the dimming level from an input on CKT 8 (GRY) or CKT 1244 (BRN). When the LCM determines that the above conditions are met, the LCM sends a signal to the instrument cluster and the radio via CKT 390 (YEL). For Buick, the radio then relays this information to the heater and A/C programmer and passenger temperature control via CKT 724 (PPL/WHT). The modules with the VF displays then adjust the dimming level of their VF displays to match the level of the incandescent lights.
LH Dimmer Module
Under the left side of the IP, on the left side of the steering column brace

you need specail radio removal tools. they spread 4 spring clips.

1. Remove the radio chassis.
2. Insert Radio Removing Tool into the radio face plate and release the radio retaining clips.
3. Pull outward on Radio Removing Tool to remove the radio chassis from the instrument panel.

Special Tool(s)

Radio Removing Tool
415-001 (T87P-19061-A)

Does it go completely black or just dim? Most displays dim when you turn the lights on to make the display darker so its not too bright. GPS and other displays do this. Do you have any problems with any other of the car's electronics?