rear wiper phantom sweep

Derski

New Member
Have a '06 TB Ext that has a weird problem. The rear wiper will do a phantom sweep engine off key out of the ignition. At first motor stopped, replaced it. Work for a day or two then stopped and the phantom sweeps started. Replaced the the LGM and programmed, wiper worked of several days then stopped again. I have checked the wiring and ground. As I am tugging on the liftgate harness I hear the lock actuator unlock but I can't find a break in the wiring. There are 2 blk ground wires I believe that go into a weird splice and one heavier wire turns into to 2 smaller gauge. At least I think it is a splice, I might be wrong as I have never seen one like this before. At one point the rear defrost wouldn't time out but that resolved with the new LGM Any help would be greatly appreciated. It is hell when you can't see out the back glass in the rain.
 

MRRSM

Lifetime VIP Supporter
Welcome to GMT Nation...

The Roof-Top to Lift Gate Tunnel (conduit) is the weak point where the Wiring to and from the LGM & Harness leading to the Wiper Motor will Short-Circuit. The Wiring inside 'work hardens' over time and can break either completely or inside of the various Class 2 and Power Wiring insulation unseen and give such sketchy behavior.

Use Automotive Quality Wire and Auto Wire Heat Shrink (Weather-Proof) to insulate the repair using Solder... NOT the Acorn and Wire-Twisting method for this repair. The attached images come courtesy GMTN Member... @jsheahawk:

jsheahawk-liftgate2.jpgjsheahawk-liftgate1.jpg
 
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Derski

New Member
Thanks for the info. I had checked the pass through harness and all of the seem fine but you are right there are a couple of hardened wires there. In moving the harness around I did find that there a odd connection 2 14 gauge wires go into a odd "tube" and one comes out the same gauge but the other is split into 2 16 gauge wires. I believe these are grounds as they are black or they could be a dark color I have tried to trace back to the module or motor but it was getting too late last night. I will see about repairing the pass through hardened wires.
 

MRRSM

Lifetime VIP Supporter
Yeah... it will be a PITA to have to Probe the Wire Harness for Continuity (Scope On A Rope)...but have a look at these images so you can isolate which wires need investigation to and from the LGM & Wiper. I'm throwing in the Databus Class 2 Network Schematics along with a BCM version, too:

LGM.jpgLGMCONNECTORSCOLORWIRES.jpgLGMTHRUTHEBOOTWIRING.jpgLGMTHRUTHEBOOTWIRING2.jpgLGMTHRUTHEBOOTWIRING3.jpgTBCLASS2NETWORK1.jpgTBCLASS2NETWORK2.jpgBCM2004DIAGRAM.jpegs-l1600E.jpg
 

Mooseman

Moderator
And there have been cases of wires broken inside the insulation and not visible until you give it a good tug or check continuity.
 
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Derski

New Member
Great thanks for the pictures and the schematics, that will really help me with this one.
 

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