2020 2500 HD work Truck tailgate not dropping

[Gabe montoya]

i’m trying to get some help with my 2020 2500 HD it’s not covered under the recall and I’m getting all three switches on the fob the dash and the tailgate to actuate the relay on the dash but the gate still is not dropping wondering if anybody else has had similar issues and if I could get a little help here, I would appreciate it the dealer stating it’s not covered under the current recalls thank you for any help 

[newdude]

26 minutes ago, Gabe montoya said:

i’m trying to get some help with my 2020 2500 HD it’s not covered under the recall and I’m getting all three switches on the fob the dash and the tailgate to actuate the relay on the dash but the gate still is not dropping wondering if anybody else has had similar issues and if I could get a little help here, I would appreciate it the dealer stating it’s not covered under the current recalls thank you for any help 

 

 

The recall was for the switch in the gate failing causing the gate to open unwanted.  You have a different issue, it won't drop.

 

Needs a tailgate actuator, the piece under the access panel that the latch rods attach to.  Pretty common failure on 19-20 1500s and 2020 HDs.  

[Gabe montoya]

I have used a power probe and it actuates fine. I only get.5 volts to the actuator when any of the buttons are pressed 

[newdude]

11 minutes ago, Gabe montoya said:

I have used a power probe and it actuates fine. I only get.5 volts to the actuator when any of the buttons are pressed 

 

.  

Edited October 8, 2024 by newdude

[newdude]

29 minutes ago, Gabe montoya said:

I have used a power probe and it actuates fine. I only get.5 volts to the actuator when any of the buttons are pressed 

 

 

TSB - 20-NA-40 1..3 (nhtsa.gov)

 

Some customers may comment on the power endgate may not unlatch or drop on first try, or under some conditions, it may not open at all.

 

Cause

The cause of the condition may be a combination of excessive spring force and low available voltage, which may cause the latch actuator to fail to function.

 

Upon verifying the condition, replace the pickup box endgate lock actuator (2) with an improved design service part. Refer to Pickup Box Endgate Lock Actuator Replacement (Power) in SI.

Edited October 8, 2024 by newdude

[Gabe montoya]

Thank you .Do have access to see what the voltage to the end gate actuator from the relay is.the TSB talks about low voltage to the actuator but never stated what it should be.thanks again for your input and time.

[newdude]

15 minutes ago, Gabe montoya said:

Thank you .Do have access to see what the voltage to the end gate actuator from the relay is.the TSB talks about low voltage to the actuator but never stated what it should be.thanks again for your input and time.

 

Endgate Release Operation (Without MutiPro Tailgate Option)

 

Interior Endgate Release Switch

The body control module monitors the voltage level of the endgate unlatch signal circuit so that when the switch is pressed contacts within the switch closes providing a ground path for the endgate unlatch signal circuit, the voltage within the signal circuit is pulled low, the body control module will detect the voltage drop and if the passenger doors are unlocked, will energize the pickup box endgate unlatch relay.

 

Exterior Endgate Release Switch

The body control module monitors the status of the vehicle doors, if the doors are locked the body control module will ignore the request from the exterior pickup box endgate control switch. If the passenger doors have been commanded to unlock, pressing the exterior pickup box endgate control switch will close contacts within the switch and provide a ground path for the endgate unlatch signal circuit, the body control module will detect the voltage drop and will energize the pickup box endgate unlatch relay.

 

If the vehicle has been equipped with the passive keyless entry system and the keyless entry transmitter is within 3 feet (1 meter) of the endgate, pressing the exterior pickup box endgate control switch will also function in the same manner but without unlocking the passenger doors. Refer to Keyless Entry System Description and Operation for more information on the passive keyless entry system.

 

Pickup Box Endgate Unlatch actuator

When body control module receives a endgate release command from the exterior pickup box endgate control switch, the body control module applies brief pulse of voltage to the pickup box endgate unlatch relay control circuit, which energizes the coil side of the relay. The switch side of the pickup box endgate unlatch relay then momentarily closes, supplying a brief pulse of battery positive voltage to the pickup box endgate unlatch actuator. The pickup box endgate unlatch actuator is continuously grounded and when it receives the voltage pulse, it will become energized and the latch will activate releasing the endgate so that it may be manually lowered to an open position.

Circuit/System Verification

1. Ignition » On / Vehicle » In Service Mode
2. Operate the component: S159E Pickup Box Endgate Control Switch - Exterior » Pressed

   Verify the component turns On and Off: E42 Tail Lamp Assembly

   • If the component does not turn On and Off

     Refer to: Circuit/System Testing — Test 1

   • If the component turns On and Off
3. Operate the component: S159E Pickup Box Endgate Control Switch - Exterior » Pressed

   Verify the component produces a clicking sound: A99C Pickup Box Endgate Latch - Center

   • If a click cannot be heard or felt

     Refer to: Circuit/System Testing — Test 2

   • If a click can be heard or felt
4. Operate the component: S157 Pickup Box Endgate Unlatch Switch @ S86 Vehicle Stability Control Switch » Pressed

   Verify the component produces a clicking sound: A99C Pickup Box Endgate Latch - Center

   • If a click cannot be heard or felt

     Refer to: Circuit/System Testing — Test 3

   • If a click can be heard or felt
5. All OK.

Circuit/System Testing

Test 1

Note: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the electrical connector: S159E Pickup Box Endgate Control Switch - Exterior
3. Test for less than 10 Ω between the test points: Ground circuit terminal 2 & Ground
   • If 10 Ω or greater
   1. Ground Connection » Disconnect
   2. Test for less than 2 Ω between the test points: Ground circuit terminal 2 @ Component harness & Ground Connection
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Repair the open/high resistance in the ground connection.
   • If less than 10 Ω
4. Ignition » On / Vehicle » In Service Mode
5. Momentarily connect a 3 A fused jumper wire between the test points: Signal circuit terminal 1 & Ground circuit terminal 2

   Verify the component turns On and Off when connecting and disconnecting the jumper wire: A99C Pickup Box Endgate Latch - Center

   • If the component does not turn On and Off
   1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
   2. Disconnect the electrical connector: K9 Body Control Module
   3. Ignition » On / Vehicle » In Service Mode
   4. Test for less than 1 V between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If 1 V or greater » Repair the short to voltage on the circuit.
      • If less than 1 V
   5. Ignition/Vehicle » Off
   6. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
   7. Test for less than 2 Ω between the test points: Signal circuit terminal 1 @ Component harness & Terminal 14 X6 @ Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Replace the component: K9 Body Control Module
   • If the component turns On and Off
6. Test or replace the component: S159E Pickup Box Endgate Control Switch - Exterior

Test 2

1. Ignition/Vehicle » Off
2. Remove the component: KR191L Pickup Box Endgate Latch Relay - Left & KR191R Pickup Box Endgate Latch Relay - Right
3. Test for less than 10 Ω between the test points:
   • Ground circuit terminal 21 & Ground @ KR191L Pickup Box Endgate Latch Relay - Left
   • Ground circuit terminal 8 & Ground @ KR191R Pickup Box Endgate Latch Relay - Right
   • Ground circuit terminal 17 & Ground @ KR191R Pickup Box Endgate Latch Relay - Right
   • If 10 Ω or greater
   1. Ground Connection » Disconnect
   2. Test for less than 2 Ω between the test points:
      • Ground circuit terminal 21 @ KR191L Pickup Box Endgate Latch Relay - Left & Ground Connection
      • Ground circuit terminal 8 @ KR191R Pickup Box Endgate Latch Relay - Right & Ground Connection
      • Ground circuit terminal 17 @ KR191R Pickup Box Endgate Latch Relay - Right & Ground Connection
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Repair the open/high resistance in the ground connection.
   • If less than 10 Ω
4. Connect a test lamp between the test points:
   • Control circuit terminal 1 & Ground circuit terminal 21 @ KR191L Pickup Box Endgate Latch Relay - Left
   • Control circuit terminal 10 & Ground circuit terminal 17 @ KR191R Pickup Box Endgate Latch Relay - Right
5. Ignition » On / Vehicle » In Service Mode
6. Operate the component: S159E Pickup Box Endgate Control Switch - Exterior » Pressed

   Verify the test lamp turns On and Off.

   • If the test lamp is always Off
   1. Ignition/Vehicle » Off & Remove » Test lamp
   2. Disconnect the electrical connector: K9 Body Control Module
   3. Test for infinite resistance between the test points:
      • Control circuit terminal 1 @ Relay Socket & Ground
      • Control circuit terminal 10 @ Relay Socket & Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
   4. Test for less than 2 Ω between the test points:
      • Control circuit terminal 1 @ Relay Socket & Terminal 11 X5 @ Control module harness
      • Control circuit terminal 10 @ Relay Socket & Terminal 9 X5 @ Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Replace the component: K9 Body Control Module
   • If the test lamp is always On
   1. Ignition/Vehicle » Off & Remove » Test lamp
   2. Disconnect the electrical connector: K9 Body Control Module
   3. Ignition » On / Vehicle » In Service Mode
   4. Test for less than 1 V between the test points:
      • Control circuit terminal 1 @ Relay Socket & Ground
      • Control circuit terminal 10 @ Relay Socket & Ground
      • If 1 V or greater » Repair the short to voltage on the circuit.
      • If less than 1 V » Replace the component: K9 Body Control Module
   • If the test lamp turns On and Off
7. Verify a test lamp turns On between the test points: B+ circuit terminal 20& Ground
   • If the test lamp does not turn On and the circuit fuse is OK
   1. Ignition/Vehicle » Off & Remove » Test lamp
   2. Test for less than 2 Ω between the test points: B+ circuit terminal 20@ Relay Socket & Output terminal @ F17DL Fuse
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Verify the fuse is OK and there is voltage at the fuse.
   • If the test lamp does not turn On and the circuit fuse is open
   1. Ignition/Vehicle » Off & Remove » Test lamp
   2. Test for infinite resistance between the test points: B+ circuit terminal 20& Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
   3. Disconnect the electrical connector: A99C Pickup Box Endgate Latch - Center
   4. Test for infinite resistance between the test points: Control circuit terminal 2 @ Relay Socket & Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
   5. Replace the component: F17DL Fuse
   6. Install the component: KR191L Pickup Box Endgate Latch Relay - Left & KR191R Pickup Box Endgate Latch Relay - Right
   7. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
   8. Ignition » On / Vehicle » In Service Mode
   9. Operate the component: S159E Pickup Box Endgate Control Switch - Exterior » Pressed

      Verify the test lamp turns On and Off.

      • If the test lamp does not turn On and Off » Test or replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right
      • If the test lamp turns On and Off » Test or replace the component: A99C Pickup Box Endgate Latch - Center
   • If the test lamp turns On
8. Ignition/Vehicle & All vehicle systems » Off
9. Install the component: KR191L Pickup Box Endgate Latch Relay - Left & KR191R Pickup Box Endgate Latch Relay - Right
10. Disconnect the electrical connector: A99C Pickup Box Endgate Latch - Center
11. Connect a test lamp between the test points: Control circuit terminal 1 & Control circuit terminal 2
12. Ignition » On / Vehicle » In Service Mode
13. Operate the component: S159E Pickup Box Endgate Control Switch - Exterior » Pressed

    Verify the test lamp state:

    Not Pressed = Test lamp Off

    Pressed = Test lamp On

    • If not the specified state
    1. Ignition/Vehicle » Off & Remove » Test lamp
    2. Remove the component: KR191L Pickup Box Endgate Latch Relay - Left & KR191R Pickup Box Endgate Latch Relay - Right
    3. Ignition » On / Vehicle » In Service Mode
    4. Test for less than 1 V between the test points:
       • Control circuit terminal 1 @ Component harness & Ground
       • Control circuit terminal 2 @ Component harness & Ground
       • If 1 V or greater » Repair the short to voltage on the circuit.
       • If less than 1 V
    5. Ignition/Vehicle » Off
    6. Test for infinite resistance between the test points:
       • Control circuit terminal 1 @ Component harness & Ground
       • Control circuit terminal 2 @ Component harness & Ground
       • If less than infinite resistance » Repair the short to ground on the circuit.
       • If infinite resistance
    7. Test for less than 2 Ω between the test points:
       • Control circuit terminal 1 @ Component harness & Terminal 2 @ Relay Socket
       • Control circuit terminal 2 @ Component harness & Terminal 18 @ Relay Socket
         • If 2 Ω or greater » Repair the open/high resistance in the circuit.
         • If less than 2 Ω » Replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right
    • If the specified state
14. Test or replace the component: A99C Pickup Box Endgate Latch - Center

Test 3

Note: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the electrical connector: S86 Vehicle Stability Control Switch
3. Test for less than 10 Ω between the test points: Ground circuit terminal 6 & Ground
   • If 10 Ω or greater
   1. Ground Connection » Disconnect
   2. Test for less than 2 Ω between the test points: Ground circuit terminal 6 @ Component harness & Ground Connection
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Repair the open/high resistance in the ground connection.
   • If less than 10 Ω
4. Ignition » On / Vehicle » In Service Mode
5. Momentarily connect a 3 A fused jumper wire between the test points: Signal circuit terminal 3 & Ground circuit terminal 6

   Verify the component turns On and Off when connecting and disconnecting the jumper wire: A99C Pickup Box Endgate Latch - Center

   • If the component does not turn On and Off
   1. Ignition/Vehicle » Off & Remove » Jumper wire(s)
   2. Disconnect the electrical connector: K9 Body Control Module
   3. Ignition » On / Vehicle » In Service Mode
   4. Test for less than 1 V between the test points: Signal circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater » Repair the short to voltage on the circuit.
      • If less than 1 V
   5. Ignition/Vehicle » Off
   6. Test for infinite resistance between the test points: Signal circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance » Repair the short to ground on the circuit.
      • If infinite resistance
   7. Test for less than 2 Ω between the test points: Signal circuit terminal 3 @ Component harness & Terminal 5 X6 @ Control module harness
      • If 2 Ω or greater » Repair the open/high resistance in the circuit.
      • If less than 2 Ω » Replace the component: K9 Body Control Module
   • If the component turns On and Off
6. Test or replace the component: S86 Vehicle Stability Control Switch

Component Testing

A99C Pickup Box Endgate Latch - Center

Caution: Complete the testing as quickly as possible in order to prevent overheating and damaging the component.

1. Ignition/Vehicle » Off
2. Disconnect the electrical connector: A99C Pickup Box Endgate Latch - Center
3. Connect a jumper wire between the test points: Control terminal 2 & Ground
4. Momentarily connect a 10 A fused jumper wire between the test points: Control terminal 1 & 12 V

   Verify the component turns On and Off when connecting and disconnecting the jumper wire: A99C Pickup Box Endgate Latch - Center

   • If the component does not turn On and Off

     Replace the component: A99C Pickup Box Endgate Latch - Center

   • If the component turns On and Off
5. All OK.

S159E Pickup Box Endgate Control Switch - Exterior

1. Ignition/Vehicle » Off
2. Disconnect the electrical connector: S159E Pickup Box Endgate Control Switch - Exterior
3. Test for infinite resistance between the test points: Signal terminal 1 & Ground terminal 2 » Not Pressed
   • If less than infinite resistance

     Replace the component: S159E Pickup Box Endgate Control Switch - Exterior

   • If infinite resistance
4. Test for less than 3 Ω between the test points: Signal terminal 1 & Ground terminal 2 » Pressed
   • If 3 Ω or greater

     Replace the component: S159E Pickup Box Endgate Control Switch - Exterior

   • If less than 3 Ω
5. All OK.

S86 Vehicle Stability Control Switch

1. Ignition/Vehicle » Off
2. Disconnect the electrical connector: S86 Vehicle Stability Control Switch
3. Test for infinite resistance between the test points: Signal terminal 3 & Ground terminal 6 » Not Pressed
   • If less than infinite resistance

     Replace the component: S86 Vehicle Stability Control Switch

   • If infinite resistance
4. Test for less than 3 Ω between the test points: Signal terminal 3 & Ground terminal 6 » Pressed
   • If 3 Ω or greater

     Replace the component: S86 Vehicle Stability Control Switch

   • If less than 3 Ω
5. All OK.

Relay Test

1. Ignition/Vehicle » Off
2. Remove the appropriate component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right
3. Test for 70 to 110 Ω between the test points: Component terminal 85 & 86
   • If not between 70 and 110 Ω

     Replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right

   • If between 70 and 110 Ω
4. Test for infinite resistance between the test points:
   • Component terminal 30 & 85
   • Component terminal 30 & 86
   • Component terminal 30 & 87
   • Component terminal 85 & 87
   • Component terminal 87A & 86
   • Component terminal 87A & 87
   • Component terminal 87A & 85
   • Component terminal 87A & 30
   • If less than infinite resistance

     Replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right

   • If infinite resistance
5. Test for less than 2 Ω between the test points: Component terminal 30 & 87A
   • If 2 Ω or greater

     Replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right

   • If less than 2 Ω
6. Connect a 3 A fused jumper wire between the test points: Component terminal 86 & 12 V

   Connect a jumper wire between the test points: Component terminal 85 & Ground

7. Test for less than 2 Ω between the test points: Component terminal 30 & 87
   • If 2 Ω or greater

     Replace the component: KR191L Pickup Box Endgate Latch Relay - Left or KR191R Pickup Box Endgate Latch Relay - Right

   • If less than 2 Ω
8. All OK.

Edited October 8, 2024 by newdude

[Gabe montoya]

Thanks so much I will work on it today after work.