Me and my GMC

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Turbogus, Apr 25, 2016.

  1. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    I can't trust any of the gauges on mine now that I know what the values truly are. The PCM controls them like idiot lights. The PCM adjusts the gauge to what it wants you to see.

    I discovered the coolant temp off one morning sitting in the valet parking line at the Houston VA. I watched it slowly rise and peak at 210° before going back down on my Torque Pro dashboard while the gauge stayed rock steady at 210°. Normally it's steady at 194° on Torque.

    One of the symptoms I noticed before replacing the battery was the gauge always stayed at 14+ indicating the alternator was always at max charge. Fifty years ago I started getting worried if it wasn't putting out at max.

  2. kennythewelder

    kennythewelder Rockstar 3 Years 1000 Posts

    Im not sure that the ECM controls your alt gauge on your 96 Burb. I know on newer cars and trucks, the BCM does control the gauges, but on a 96 IDK if you even have a BCM. Any way, here are pics of what is in my Haynes man. 20160805_143945.jpg 20160805_143908.jpg
    xPosTech likes this.
  3. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    You're right, Kenny. I should have mentioned my truck is a 2010 and my experience was just anecdotal.

  4. Turbogus

    Turbogus Active Member 1 Year 100 Posts

    THANKS Kenny! since I can't pony up for a manual on welfare, thats a great help. Mind you, I'm saving up for the OE manual, been a penchant of mine since I first got my 'go fast' a '78 Kawasaki Z1R TC. Next trip to the wrecking yard I'm going to take a closer look at disassembled gauge binnacles.
    Just this morning the voltmeter for the second time in three months registered 14V, that is, until the ABS light came on then poof it dropped down to the level in my posted pic.
    kennythewelder likes this.
  5. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    You might find a PDF version of the service manual online. Spend a few minutes googling for free or downloadable manuals. You might be surprised. Also check with your local library. Some have complete sets of factory service manuals. And some of the libraries make the manuals available online. You might need to be a member to access them. A 96 Suburban shouldn't be hard to find.

    kennythewelder likes this.
  6. Turbogus

    Turbogus Active Member 1 Year 100 Posts

    Thanks Ted, what with my 7 day working week it's hard for me to get out and about. On a sidebar, this mornings startup the Voltmeter went 5 full minutes before snapping from 14V (indicated) down to 12V. It was almost like a relay had switched in so sudden that it was.
    I may connect an external Volt and Amp meters so I can really judge what's going on. I reckon I should stick to my idiom of always augmenting factory 'idiot gauges' with mechanical (in the case of temp and oil pressure) on all of my rigs since I ran a '66 Malibu with my first pro built 4 bolt main 350 with a 10/10 steel crank and forged rods/pistons and 461 heads. What a great SBC that was, pity I had to let it go during my financial meltdown back in '91
    Last edited: Aug 7, 2016
  7. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Those kind of problems make me suspect bad dash module solder joints.
  8. Turbogus

    Turbogus Active Member 1 Year 100 Posts

    Regarding that dash module, I've been to the boneyard a few times and I've seen GM's with the dash removed and the gauge panel exposed, but with no visible mounting tabs or bolts. Does anyone know how these things come out?
  9. Turbogus

    Turbogus Active Member 1 Year 100 Posts

    I recently purchased the Innova 3020c and plugging it in to the OBD2 port I noticed the voltmeter began reading normally and the ABS light went out. Removing it and the ABS light turned on again after the next startup, subsequently when I leave the dingus plugged in, no ABS light.
  10. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    Flakey grounds can make for some truly strange symptoms. And sometimes unplugging and reinserting connectors can clear high resistance cable connectors. Try the connectors at the ECM.

    RayVoy likes this.

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