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Thread: Lb7 gauge cluster question

  1. #1
    Join Date
    Aug 2014
    Location
    Orleans,IN
    Posts
    6

    Default Lb7 gauge cluster question

    The gauge cluster in my 02lb7 has been going crazy lately. It will shut off while I'm driving, the battery light will pop on and the airbag light will pop on. The truck is running fine. The gauges just start going crazy while driving. Any idea what the issue could be? Thanks for the help

  2. #2
    Join Date
    Feb 2000
    Location
    Montana
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    11,382

  3. #3

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    Threads kind of old but in case you are still having issues thought I'd hop on. I had issues with my dash a few years ago. Specifically the DIC and PRNDL would sometimes go dim/dark. I pulled the board and started poking around to debug, checking for shorts, etc. Through lots of messing around I noticed that if I pushed on part of the board the PRNDL would get bright again. I was slightly bending the board and causing it to flex. Figured out that some of the solder connections had cracked over time, probably from vibration and just aging. The flex on the board was making some cracked solder joints connect better. Took a soldering iron and reheated the connections, especially around the connector. That was almost 2 years ago and the dash has worked like a champ since then.

    I think with the lights coming and going it may be easier to debug (at least if you can reproduce). The DIC, PRNDL, and stepper gauges are all controlled over the serial bus but I think the idiot lights are direct 12V connections over the connector (at least on my LB7). You can easily check with a multi-meter if you are getting signal at the pins. Then you can start to trace if it's a problem with the board or what is sending the signals. If you need a pin-out or a wiring diagram I can probably dig one up (the 02 should be the same as my 03). I seem to recall it's a 2 layer PCB so I could visually follow the circuit, makes it easier to check for shorts and to see what components could be at fault.

    Good luck

  4. #4
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

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    Good advice Todd!

    There was a problem with the wiper motor control circuit board in the 1990s GM trucks that could also be solved by re-heating/soldering the connections for the electrical connector. Maybe this is a problem that affects automotive circuits more so than home electronics...

    Happy New Year!

  5. #5
    Join Date
    Mar 2000
    Location
    Owego, NY
    Posts
    1,929

    Thumbs up

    Quote Originally Posted by todd.walter View Post
    ... I had issues with my dash a few years ago. Specifically the DIC and PRNDL would sometimes go dim/dark...Figured out that some of the solder connections had cracked over time ... Took a soldering iron and reheated the connections, especially around the connector. That was almost 2 years ago and the dash has worked like a champ since then.
    Todd, thanks for sharing.. I've had the same issue going on with my 03 for a while .. The DIC/PRNDL display is very DIM at start up but comes up to normal brightness after a few minutes. Now I know the fix .. Thanks, Bill
    Bill
    03 2500HD D/A CC/SB/4WD,OilGuard, MegaFilter,LiftPump/PreFilter, Bilsteins,RetraxRollTop,J&J Boards,Coolant Filter,AlliDeepPan,FastIdle,AllHeadLightsOn,
    98 K3500 6.5,SOLD

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