Need wiring diagram of rear-window defogger circuit for 2008 Chevy Impala LT

System Description NEEL0216 MODELS WITHOUT POWER DOOR LOCKS NEEL0216S01 The rear window defogger system is controlled by the rear window defogger timer. The rear window defogger operates only for approximately 15 minutes. The rear window defogger switch is integral to the air control. Power is supplied at all times
to rear window defogger relay terminal 5
through 20A fuse [No. 25, located in the fuse block (J/B)]. With the ignition switch in the ON or START position, power is supplied
through 10A fuse [No. 5, located in the fuse block (J/B)]
to rear window defogger relay terminal 1, and
to rear window defogger timer terminal 1. Ground is supplied to air control (rear window defogger switch) terminal 8 and rear window defogger timer terminal 4 through body grounds M14 and M68. With the rear window defogger switch (located in air control) ON, ground is supplied
to rear window defogger timer terminal 3
through air control (rear window defogger switch) terminal 8. Rear window defogger timer terminal 2 then supplies ground to the rear window defogger relay terminal 2. With power and ground supplied, the rear window defogger relay is energized. Power is supplied
through terminal 3 of the rear window defogger relay
to rear window defogger terminal +. Rear window defogger terminal - is grounded through body ground R102. With power and ground supplied, the rear window defogger filaments heat and defog the rear window. When the system is activated, the rear window defogger indicator illuminates in the air control. Power is supplied
from rear window defogger relay terminal 3
to air control (rear window defogger switch) terminal 4. Air control terminal 8 is grounded through body grounds M14 and M68. MODELS WITH POWER DOOR LOCKS NEEL0216S02 The rear window defogger system is controlled by the smart entrance control unit. The rear window defogger operates only for approximately 15 minutes. The rear window defogger switch is integral to the air control. Power is supplied at all times
to rear window defogger relay terminal 5
through 20A fuse [No. 25, located in the fuse block (J/B)] and
to smart entrance control unit terminal 49
through 7.5A fuse [No. 28, located in the fuse block (J/B)]. With the ignition switch in the ON or START position, power is supplied
through 10A fuse [No. 5, located in the fuse block (J/B)]
to rear window defogger relay terminal 1 and
to smart entrance control unit terminal 27. Ground is supplied to air control (rear window defogger switch) terminal 8 and smart entrance control unit terminals 43 and 64 through body grounds M14 and M68. With the rear window defogger switch (located in air control) ON, ground is supplied
to smart entrance control unit terminal 14
through air control (rear window defogger switch) terminal 1. Smart entrance control unit terminal 37 then supplies ground to the rear window defogger relay terminal 2. With power and ground supplied, the rear window defogger relay is energized. Power is supplied
through terminal 3 of the rear window defogger relay
to rear window defogger terminal +.
Rear window defogger terminal - is grounded through body ground R102. With power and ground supplied, the rear window defogger filaments heat and defog the rear window. When the system is activated, the rear window defogger indicator illuminates in the air control. Power is supplied
from rear window defogger relay terminal 3
to air control (rear window defogger switch) terminal 4. Air control (rear window defogger switch) terminal 8 is grounded through body grounds M14 and M68

You can see fuse, correct. With rear defogger turned on, use test light, see if any voltage at fuse or if fuse is blown? Also, check continuity on defogger grid, if no continuity, there is a break in the grid. If you can find the break, hopefully your local auto store has continuity paint that you can paint over the break to restore continuity.

Doesn't use a relay , controlled by lift gate control module . Your best bet , take it to a qualified repair shop .
Rear Window Defogger System Components
The rear window defogger system consist of the following components:
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HVAC control module

?€¢
Liftgate module (LGM)/endgate module (EGM)

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Rear window defogger grid

Rear Window Defogger Operation (With LGM)
Battery positive voltage is supplied through the LGM 2 fuse to the LGM for the rear window defogger system. When the rear window defogger switch is depressed, the HVAC control module illuminates the rear window defogger indicator, and sends a class 2 message to the LGM to enable the rear window defogger. The LGM enables the rear window defogger by allowing battery positive voltage to the rear window defogger.
When the rear window defogger switch is pressed for the first time, the defogger cycle lasts 10 minutes. Further operation results in 10 minute defogger cycles.
DTC B0283 Electric Rear Defrost Circuit - do you know what DTC'S - diagnostic trouble code's are ?
Circuit Description
The liftgate module (LGM)/endgate module (EGM) monitors the voltage level on the supply voltage circuit of the rear window defogger. The LGM/EGM test the supply voltage circuit of the rear window defogger every 160 milliseconds. With the rear window defogger inactive, the supply voltage circuit of the rear window defogger will have no voltage present. With the rear window defogger active, the supply voltage circuit of the rear window defogger will be near system voltage.

Fuse box rear , fuse #23 30 amp ! Do you know where this is located ? There is also a relay for the Rear window defogger , located in the same rear fuse box .
Fuse Block - Rear
Left side of the luggage compartment, behind the left rear wheel well . But you really need to know how it works , you can check fuse an relay .
Rear Window Defogger Operation
Battery positive voltage is supplied through the BATT 1 fuse in the underhood fuse block to the rear defog relay switched input. When the rear defog switch button is pressed, the body control module (BCM) energizes the rear defog relay by providing a B+ to the control circuit of the rear defog relay. This allows battery positive voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger grid. The HVAC control module houses the rear defog switch and also illuminates the rear defog indicator on the switch button, upon this request. Ground for the rear window defogger grid is provided by G301 for the Sedan or G302 For the Extended Sedan.

Rear Window Defogger System Components
The rear window defogger system consist of the following components:
• HVAC control module
• Body control module (BCM)
• DEFOG relay
• Rear window defogger grid
Rear Window Defogger Operation
When you turn the ignition to the ON position, ignition voltage is supplied to the DEFOG relay coil. Battery positive voltage is supplied at all times to the DEFOG relay switched input. When the rear window defogger switch is depressed, the HVAC control module illuminates the rear window defogger indicator and sends a class 2 message to the BCM. The BCM energizes the DEFOG relay by grounding the control circuit of the relay. This allows battery positive voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger. Ground for the rear window defogger is provided by G306 or G390 (crew cab).
When you turn ON the ignition and press the rear window defogger switch for the first time, the defogger cycle lasts 10 minutes. Further operation results in 5 minute defogger cycles.

Do you know what your messing with ? What's the problem ?

[PDF]Wiring Diagram.pdf - Ken Gilbert

ken-gilbert.com/wrx/mans/99.../Wiring%20Diagram.pdf

Each connector number shown in the wiring dia- ... Rear defogger cord (Ground). Fuel tank cord,. Roof cord, ... circuit. Then check the switch, relay, fuse, ground, etc. 4. .....Rear wiper motor. Rear wiper ... License plate light RH. Tail light LH.

#? license plate light - Circuit Wiring Diagrams

circuitswiring.com/tag/license-plate-light/

2008 Volkswagen Newbeetle Main Fuse Box Diagram 2008 Volkswagen Newbeetle ...Parts: rear window defogger, shift lock, battery positive voltage, interior light, A/C clutch, ... brake light, daytime driving light, wiper and washer system, vacan, fuel pump, central ... 1997 Suzuki Geo Tracker Left Dash Fuse Box Diagram.

#? license plate light - Circuit Wiring Diagrams - Page 3

circuitswiring.com/tag/license-plate-light/page/3/

Audi A4 Engine Fuse Box Diagram Audi A4 Engine Fuse Box Map Fuse Panel ... mirror control, wiper, washer, horn, brake light, cruise control, heated rear window, ... 2003Suzuki Aerio Dash Fuse Box Diagram 2003 Suzuki Aerio Dash Fuse Box ... rear defroster, fuel injection controller, radio, A/T controller, hazard light, ...

Switch, fuse or maybe the wiring to the window has come loose or off, happens alot, kits are available at local auto parts stores...
I hope that helps...

There may be a fuse in the fuse panel under dash, but defoggers are often found with a circuit breaker rather than a fuse. There may also be a relay in the circuit to the rear window. You could pull off the connector at the window, and with key on and defogger switch on, check for power at the connector. If you have power, one of the grid wires on the window may be broken. Kits are available to fix that.
If no power at the window, IDK, may have to find a wiring diagram, or have an electrician or mechanic start looking into it. Good luck.

i just fixed my car to the exact question above, it took 20 minutes total. yes I\'m good with a wrench, but this fix doesn\'t reqire you to be.

Problem: Rear defroster doesn\'t work, but the fuse is good and the little light comes on on the button.

Answer: Go to front passenger kick panel where the "other" fise box is and remove the pastic panel, it just pops straight up. Under the fuse block is a white plug that connects front wire harness to the rear harness. this is where the problem is. pull the connector off the body, my plugslide straight back. Now flip the whole connector over, there you\'ll see the burnt spot on the plug. losse, corroded connection causes melt down. this stuff happens. my car has a purple wire going into the plug and a black one coming out, this is the rear defroster wire. cut the purple wire aleast a half inch before the plug and cut the black one coming out of the plug the same, always leave a little wire incase you ever want to reuse that terminal, standard rule. now take two butt connectoers and a four inch piece of ten gauge and splice the purple and black wires back together. lots of current so DO NOT use 12-14 gauage wire, it will melt. and Wa-La, its fixed!! since you dont have to do the trouble shooting and chase down the wires like i did, should take you ten minutes to fix.

Now if this doesn\'t fix your car, then don\'t pay me!!

If this DOES fix your car, then take your wife out to dinner with the $150.00 i just saved you from having to take it to the dealer,

(they would sale you new connectors and harness)

Rear Defogger Inoperative, But Heated Mirrors Operate Correctly
1. Connect scan tool. Turn ignition switch to RUN position. Turn rear defogger on. Using scan tool, display BCM
outputs. If rear defogger is being requested on, go to next step. If rear defogger is not being requested on, go to
step 10).
2. Ensure ignition switch is in RUN position. Remove rear defogger relay from rear junction block, located on center
right rear of passenger compartment, under rear seat. Connect test light between ground and defogger relay
harness connector terminal F3 (Brown wire). If test light illuminates, go to next step. If test light does not
illuminate, go to step 11).
3. Connect test light between ground and defogger relay harness connector terminal A2 (Red wire). If test light
illuminates, go to next step. If test light does not illuminate, go to step 12).
4. Connect test light between defogger relay harness connector terminals A2 (Red wire) and B3 (Purple wire). If test
light illuminates, go to step 13). If light does not illuminate, go to next step.
5. Disconnect rear defogger positive and negative feed bus connectors. Connect a jumper wire between defogger
relay harness connector terminals F3 (Brown wire) and A4 (White wire). Connect test light between ground and
positive feed bus connector terminal "A" (Black wire). If test light illuminates, go to next step. If test light does not
illuminate, go to step 8).
6. Connect test light between positive feed bus connector terminal "A" (Black wire) and negative feed bus connector
terminal "B" (Black wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 9).
7. Repair open in Black wire between rear defogger and ground. Recheck system operation.
8. Repair open in Purple wire between rear junction block and heated backlight antenna module. Recheck system
operation.
9. Check for proper terminal contact at rear defogger connectors. Repair as necessary. Recheck system operation.
10. Check for proper terminal contact at BCM. If terminal contact is okay, replace BCM. Recheck system operation.
11. Repair open in Brown wire between rear junction block and instrument panel junction block. Recheck system
operation.
12. Repair open in Red wire between rear junction block and underhood junction block (located in right front corner of
engine compartment, between battery and strut tower). Recheck system operation.
13. Connect test light between defogger relay harness connector terminals F3 (Brown wire) and A4 (White wire). If
test light illuminates, go to next step. If test light does not illuminate, go to step 16).
14. Reinstall defogger relay. Disconnect BCM 32-pin Pink connector C2. BCM is located behind right side of instrument
panel, near rear of glove box. Using DVOM, check voltage between ground and BCM harness connector C2
terminal A3 (White wire). If any voltage is present, go to next step. If no voltage is present, go to step 17).
15. Repair open or short to ground in White wire between rear junction block and BCM. Recheck system operation.
16. Check for poor connection at defogger relay terminals. If connections are okay, replace defogger relay. Recheck
system operation.
17. Check for proper terminal contact at BCM. If terminal contact is okay, replace BCM. Recheck system operation.