Lights won't dim

Could be the instrument cluster .GM had instrument cluster problems for 2003 to 2006 . Wouldn't think BCM reprogramming to be an issue . Having a qualified repair shop or dealer check for DTC'S - diagnostic trouble codes an view data parmeters would be the first place to start .
When the ignition switch is turned to the RUN position, the instrument panel cluster (IPC), radio VF display, and the HVAC control assembly turns ON at maximum brightness. When the headlamp switch is in the PARK or HEADLAMP ON position, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. The dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The BCM supplies a voltage reference through the I/P dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P lamps supply voltage circuits and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.

DTC B2652
Circuit/System Description
The BCM supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the instrument panel lamp supply voltage circuit illuminating the components listed below:
• Headlamp switch
• Instrument panel cluster (IPC)
• Driver and passenger window switches
• Driver and passenger door lock switches
• Outside rearview mirror switch

Circuit/System Testing
Ignition OFF, disconnect the (C2) harness connector at the BCM.
Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
? If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the supply voltage circuits listed below for a short to ground.
• Instrument panel lamp supply voltage circuit terminal 3 C2
• Instrument panel lamp supply voltage circuit terminal 3 C6
Ignition OFF, disconnect all of the instrument panel lamp components fed by the BCM supply voltage circuits listed below.
• Instrument panel supply voltage circuit -terminal 3 C2
• Instrument panel supply voltage circuit -terminal 3 C6
Ignition ON, with a scan tool clear the DTC.
Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset.
? If the DTC resets, test the instrument panel lamp supply voltage circuit for a short to ground. If the circuit test normal, replace the BCM.
Reconnect each component one at a time and verify that the DTC does not reset as current.
? If the DTC resets as current, test or replace the component responsible for setting the DTC.
DTC B3600
DTC B1395 03 : Device Voltage Output 1 Circuit Voltage Below Threshold
DTC B1395 07 : Device Voltage Output 1 Circuit Voltage Above Threshold

Interior Backlighting Malfunction
Diagnostic Fault Information
Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance
I/P Dimming Voltage Reference
B1395 03, B3600 03
B1395 03
1, 2
--
Instrument Panel Lamps Dimmer Switch Signal
B3600 03
B3600 03
1, 2
--
Instrument Panel Lamp Supply Voltage
B2652 00
1
1
--
LED Dimming Supply
B2610 00
2
2
--
Headlamp Switch Ground
--
3
--
--
Instrument Panel Lamps Malfunction
LED Malfunction
Headlamps and Dimmer Switch Malfunction

. The illumination is controlled by the BCM - body control module .
Interior Lamps Dimming
This group includes lamps which may dim. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.
• HVAC control module, head assembly
• Rear HVAC control module, head assembly
• Radio
• Rear seat Audio
• The instrument panel cluster (IPC)
• The PRNDL lamp, with the exception of the current gear select position
• Power window switches
• Various switches
When the ignition switch is turned to the ON position, the 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 instrument panel (I/P) dimmer switch. At the same time all 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 I/P dimmer switch through the I/P dimming lamps control circuit. The setting of the I/P dimmer switch determines the amount of voltage that the I/P dimmer switch supplies to the BCM through the I/P dimming lamps low reference circuit. The BCM then sends a pulse width modulation (PWM) voltage to all the interior lamps. All the VF and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the park lamp or headlamp position, all incandescent back lighting turn ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.


Do you know what DTC'S - diagnostic trouble codes are ? Codes set in the BCM
DTC B2610 00: Passenger Compartment Dimming 1 Circuit
DTC B2615 00: Passenger Compartment Dimming 2 Circuit
DTC B2652 00: Passenger Compartment Dimming 3
Circuit/System Description
The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. Ground for the I/P dimmer switch is provided at G201.

sunroof fuse 1 20amp / power windows - circuit breaker 25 amp
both of these are located in the instrument panel fuse box .

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 ?

The sensor is usually located on the top of your dashboard. You might see it if you look into your vehicle through your windshield at your dash.
I have seen( one time ) that a gps was bright enough that it caused the dash lights not to come on because the sensor thought it was light outside.
Or you could have gotten a bad sensor.

Sounds like that dimmer you ruined
You must turn off power when replacing
And test the wires

The Leviton 6681 is a push-button rotary-type incandescent dimmer with 600Watt capacity

If you have incandescent bulbs, the dimmer should work.
If the dimmer has different color wires, try reversing the wires.
If the dimmer replaced a 3-way switch, then this is not the right dimmer.
If you have compact florescent bulbs, you need a dimmer that also dims florescent.

http://www.google.com/products/catalog
Link shows the Leviton 6673 incandescent and florescent dimmer

But you also need dimmable compact florescent bulbs.
http://www.amazon.com/DIMMABLE-COMPACT-FLUORESCENT-LIGHT-SPIRAL/dp/B0014B84ZM

All your wiring looks good. Many times dimmer just have problems and are faulty. You should note that the dimmer can only handle 600 watts. If you have that or more on it, than you have probably fried the dimming mechanism. In either case the dimming mechanism is not working properly and you will have to take it back and get the same dimmer or a different one. Tell the store they sold you a faulty dimmer and you can get a replacement at no cost.

In general practice, you can only install ONE 3-way dimmer switch to control the lights. If you use two regular 3-way dimmer switches, the circuit won't work.

However, newer technology allows for double 3-way dimming from different locations. See this article about how to do this:

http://www.smarthome.com/2494M3/SwitchLinc-3-Way-Dimmer-INSTEON-3-Way-Dimmer-Kit/p.aspx

Questions to answer so I can answer/resolve your problem:

1) Is this a rotary style dimmer?
2) Is it a toggle or slider type?
3) Is this on a 3-way circuit (that has 2 or more switches that can turn the lights on or off)
4) Is this on a single switch circuit?
5) Is this a brand new dimmer switch?
6) Is this an old dimmer switch?
7) Are the light bulbs in the spots regular incandesant or halogen bulbs?
8) Are the light bulbs in the spots CFL (compact flouresent lamps)?

With this information, I can tell you what the problem is:

If you answer "YES" to #1, and or #6 then the dimmer is faulty and should be replaced.

If you answer "YES" to #8, then you have the wrong dimmer for the bulb type, as CFL's require a specific dimmer type in order to dim them.

Please provide some more info and maybe we can help you figure out what's wrong.

Hope you find this Very Helpful and best regards!

florecent bulbs wont dim unless they are dimmable.