Results 1 to 3 of 3

Thread: Can I use a 2008 engine harness on a 2009 Silverado?

  1. #1
    Senior Member
    Join Date
    May 2014
    Posts
    119

    Question Can I use a 2008 engine harness on a 2009 Silverado?

    Lets talk 2008 vs. 2009 Transmission Wiring

    My 2009 Silverado LY5 never had a PRNDL switch as it was internal to the trans., which was a pain in the ass when it came to swapping in a 4L80E ... while I had to swap the required blue? wire at the T42 connector, I had to also add a PRNDL switch to the harness, and also run 3 extra wires for fluid pressure switches in the 4L80E. It's all been working fine for over 2 years/12000 miles.

    Now my engine harness, over the years, has been hacked and chopped ... and even though it works perfectly fine, I'm looking to get a new one from GM as they're not that expensive in the grand scheme of things (~$250).
    wholesalegmpartsonline.com customer service wants to know if I have a wire at transmission connector cavity-6 ...

    There are 2 different listings for the vin provided. Need to know with or without wire at cavity 6 on the transmission connector
    20822434 HARNESS, ENG WRG (W/O WIRE AT CAVITY 6 FOR 4SPD TRANS CONN) (FOR 1ST DES SEE 20757824) C1 (03-53) 5.3-0 FLEX FUEL W/CYL DEACTIVATION (LMG),5.3J W/CYLINDER DEACTIVATION (LY5),4-SPD AUTO TRANS (M30), (2ND DES) 2009-2009 01 381.57 12H 3320A
    20757824 HARNESS, ENG WRG (W/WIRE AT CAVITY 6 FOR 4SPD TRANS CONN) (FOR 2ND DES SEE 20822434) C1 (03-53) 5.3-0 FLEX FUEL W/CYL DEACTIVATION (LMG),5.3J W/CYLINDER DEACTIVATION (LY5),4-SPD AUTO TRANS (M30), (1ST DES) 2009-2009 01 340.84 12H 3320A
    Well, at the tranmission, there is a wire at Pin-6(f) and at the T42 connector, there is the Serial BUS + wire at Pin-6

    So, on to the questions...

    Do I go with 20757824?

    Does that mean that the other harness listed probably has the PRNDL switch from the 2008 trucks?

    Can I just go with a harness from a 2008 truck? Has anything with the engine side been changed? I'm assuming only the trans harness was changed to remove the PRNDL switch wiring and incorporate it to the single round plug.

    Or should I just go with the harness listed for my truck and do the required mods again so I can use it?
    Either way, I need to move a few wires around. I've already made the adapter harness (pic), just need to add 3 wires to the main harness for the TFP switches and mode the speed sensor signal at the T42 connector.

    Thanks in advance, I know I'm overthinking this some...
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	trans adapter.jpg 
Views:	23 
Size:	78.6 KB 
ID:	22665  

  2. #2
    Lifetime Member ChipsByAl's Avatar
    Join Date
    Feb 2006
    Posts
    581

    Default

    Well you know what will work for sure! Nowadays harnesses can have subtle differences that need to be checked pin for pin. Since you have the adapter, that's the way I would go.
    Al
    "Trash that carb and get Injected!"

  3. #3
    Senior Member
    Join Date
    May 2014
    Posts
    119

    Default

    Quote Originally Posted by ChipsByAl View Post
    Well you know what will work for sure! Nowadays harnesses can have subtle differences that need to be checked pin for pin. Since you have the adapter, that's the way I would go.
    Al
    Well now when I put that harness on their page, it says is discontinued and replaced by the OTHER part number 20822434 ... haha I guess its a gamble now because I can get the new part cheaper from another site, which also sells the older part number 20757824

Similar Threads

  1. 2009 Silverado 6 cyl Engine swap to 6.0 e-force SC setup issues
    By mowton in forum E37, E38 & E67 PFI ECM's
    Replies: 19
    Last Post: April 21st, 2014, 12:33 PM
  2. 2009 Silverado 4.3l/4l60 to a 6.2/4l80 engine/trans swap = ABS lite
    By mowton in forum Conversions / Aftermarket Parts
    Replies: 0
    Last Post: May 13th, 2012, 03:38 AM
  3. 2008 Silverado 2WD converted to 4 WD
    By GAMEOVER in forum 4speed RWD/FWD Transmission Tuning (incl T42)
    Replies: 8
    Last Post: September 6th, 2011, 02:14 AM
  4. 2008 silverado 4.3 V6 mileage?
    By trashygasman in forum E37, E38 & E67 PFI ECM's
    Replies: 5
    Last Post: May 16th, 2011, 02:54 AM
  5. Tune for a 2008 silverado w/4.8
    By johnj in forum General (Petrol, Gas, Ethanol)
    Replies: 0
    Last Post: March 7th, 2011, 11:28 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •