NEED HELP no rear wiper no rear latch release

byteme

Original poster
Member
Jun 21, 2019
14
shado001
05 ive tested for grounds and they appear good rear lic plate lights work fine checked in the one loom ( top of hatch )no breaks in wires .Im getting power to the wiper motor and the actuator but nothing works . Click inside actuator is very faint ive ran a good known ground to each component and still no change ???
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Did you actually tug and pull on the wires in the hatch boot? They have a tendency of breaking inside the insulation.

Is there anything else related to the tailgate module that isn't working, like the key fobs?
 

byteme

Original poster
Member
Jun 21, 2019
14
shado001
Did you actually tug and pull on the wires in the hatch boot? They have a tendency of breaking inside the insulation.

Is there anything else related to the tailgate module that isn't working, like the key fobs?
no everything with the fob is fine locks etc on rest of the vehicle , theres a constant feed to the wiper motor , i tested with a volt meter and ground seems fine on the actuator and the wiper motor
 

budwich

Member
Jun 16, 2013
2,027
kanata
use your meter and meter the resistance (towards the motor) of those points on the connector. There should be some ... but not a short or not "infinite". Go from there.
 

mrrsm

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byteme

Original poster
Member
Jun 21, 2019
14
shado001
Okay so your gonna think this is weird .. I was also gettin a code for clutch fan.. After checking everything grounds etc etc in the mean time i reassembled the year latch assembly and put it in. no click nothing still The battery went low so good time to clean the terminals clear the code .. got that all done, ses is out off to the drive in when i hit the locks at the store that distinctive clank in the hatch went off SOB .. But now the rear access light is one causing issues with alarm and of course the rear wiper will not move if the thing thinks the hatch is open . When i disassembled the back taking the cover off the one switch came off its mount by the glass . I there more then two sensors on the back end ive closed the circuit and still shows access open . The light will randomly go out when i hit a bump .Last night all it wanted to do was chime its head off .
 

byteme

Original poster
Member
Jun 21, 2019
14
shado001
that sounds like the motor pump is getting power so ground should be goo
d
 

mrrsm

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The Problem with the Lift Gate area of any GMT360 Vehicle is that it can be a Tragedy in (4) Acts best described as follows:

(1) As per @Mooseman ... The Wiper Motor Circuitry coming from the LGM (Lift Gate Module) gets routed through a Rubber Boot shielding the harness from the Elements (which includes the Power Circuit and the Class 2 Network Control Circuit). Occasionally… the Wires hidden inside of the “Ribbed Rectangular Elbow” can work-harden and completely break and separate... or make contact and short-circuit the Wiper Motor and separating the LGM Control from it.

(2) The Door Lock Circuitry coming from the LGM can get interrupted if the LGM Plug-Connector develops a “contact breaker” syndrome… essentially frying the mating Logic Board contacts and melting the Plastic Body of the LGM. After the metal tines lose their Cadmium Plating… the flat steel tines inside of the Power Connector to the LGM will Rust and Corrode and make constant electrical contact very sketchy.

(3) The Lift Gate Windows Circuitry can suffer from a loss of Class 2 Network Bi-Directional Communication between the LGM and the BCM… and likewise mess with the behavior of the Remote Key-Fob Alarm activity as well.

(4) The Physical Lock-Work securing the Lift Gate Latch to the Body of the SUV when the Hatch is Closed can become Rusted, Corroded, Jammed and fail to do its job… a Mechanical Failure that needs taking apart and attending to. Likewise the Glass Locking Mechanism is also subject to a Mechanical Failure in a similar manner. Removing the Inner Panel and the Plastic Fascia from around these locations is necessary to investigate and repair anything that has gone physically sideways. You may have a combination of Electrical AND Mechanical issues to deal with.

The problem with this arrangement is also that the Lift Gate Module will occasionally lose communication with the BCM and the odd problem is that failures with the LGM can have a profound negative effect on OTHER Modules on the Class 2 Network. These two Threads have much to say over the entire range of problems with this LGM and Lift Gate menagerie. Some of this information covers the Wiper Motor. Some the Locking Mechanism issues… and of course some covers the Class 2 Network communications problems. Everything herein… is worth knowing from a careful read of these Threads.

The ways that the PCM and the BCM allow for ALL of the Modules to meet along a "single wire" for PWM Communications (Pulse Width Modulation at 0-5 Volts DC) that can make the SUV susceptible to Bizarre Module behavior when any one of these fails to work properly. And so, I’ve included a Color Schematic of the complete Class 2 Network Circuitry so you can compare the subtle wire colors of each Plug connection shown in the other added images against the wire tracings on the schematic if you decide to probe for continuity and physical examination.

https://gmtnation.com/forums/threads/lift-gate-control-module.8883/

https://gmtnation.com/forums/threads/liftgate-control-module.8114/

GMCLASS2NETWORK.jpegLGMDISASSEMBLED.jpgLGMHARNESSWIRECOLORS.jpgLGMHARNESSWIREDAMAGE.jpgLGMHARNESSWIREDAMAGE1.jpgLGMLOGICBOARDAMAGE.jpgLGMTHRUTHEBOOTWIRING.jpgLGMTHRUTHEBOOTWIRING2.jpgLGMTHRUTHEBOOTWIRING3.jpgs-l1600A.jpgLGM.jpgLGMPLASTICASEDAMAGE.jpgLGMHARNESSWIRECOLORS1.jpgs-l1600D.jpgs-l1600.jpg
 
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mrrsm

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Regarding an Inoperative Lift Gate Latch Mechanism covered above as Item (4)… THIS Video shows an intrepid Trailblazer Owner confronted with this Dilemma and How he Solves the Problem with all of the ‘R&R Shenanigans’ he endures on this Roller-Coaster Ride for its Repair:


WOW... @Mooseman... Talk about "Having a Deja Vu"...

MOOSEMANDEJAVU5.jpg
 
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