Have an 02 GMC 2500 Crew Short box Duramax/Allison, completely stock except high idle to ECM installed, and I have a problem. The shift indicator/odometer will go blank on occassion. Mostly at morning startup, sometimes when traveling. It'll come on after a while and go out after a while, no bumps on road, no shifts, cruise set or not. It ALWAYS shifts correctly when the display is blank, and when the display is lite up. It puts up a code "U1000", data link failure.....? Dealer checked, replaced park/neutrel positon switch, checked grounds, plugs, connectors, continuity, wire resistance. Now GM Tech says replace TCM - $1500 Cdn. No gaurentees.....,thats a problem. Out of warranty, etc.


Any helpfull ideas? Is there jobber TCMs?


Thx;


Turnpike.

dont see the TCM as fault, if all external checks ok, I would even suspect a faulty cluster.


Intermittants are tough though.... guessing is sometimes a last resort... educated guesses of course


http://www.dieselplace.com/forum/smileys/Embarrased.gif

My 2001 D/A does the exact same thing. I thought it might be related to the wire that is soldered to the back of the cluster, for my ats co-pilot. that's why I have not taken it in to the dealer. All I do to make the light come back on is push the trip reset a few times and it works.

My '03 does the same thing. Normally on start up (does not matter if the engine is warm or cold, it will go blank on start at a fuel stop after an hour run as easily as it will 1st thing in the AM. So far, it an intermittent problem that I can't quite pin down. My truck is well pas the 36K warranty, so I am expecting the dash to fall off at any time. http://www.dieselplace.com/forum/smileys/Ermm.gif


As a side note, my fan speed control on the A/C works intermintently also. Some time when I press the switch, nothing happens, after I release the switch & re-press it, the fan will switch speeds. . . .weird. Of course, when I took it in to the dealer, I played with the fan for 15 min & could not replicate. Was out or the road for 10 miles . . . & faulted out twice! http://www.dieselplace.com/forum/smileys/Clap.gif


Oh well.

Hi Again,


On again, off again all week-end. This morning it went blank on way to work. Parked, flipped up tilt steering and saw it blink. Pounded on steering wheel and it lite up, again and it went out. Also when I started it this PM. Took to dealer and asked them to check for loose connection in the dash or cluster.


Up-dates later;


Turnpike

Sounds like a burned up ignition switch to me. We've seen the identical complaint on quite a few Suburbans at my repair shop.

End of story....hopefully.


Dealer was able to tease the lite by a slight twist, so they put in a re-manufactured cluster, and all seems to work good now.


Thanks for the help


later


turnpike

I'd be surprised if it wasn't the ignition switch. If all is well now then I guess you found your problem. If the problem arises again, PM me. I'd like to offer up a few suggestions.

As part of the process of trying to find the problem I worked the ignition switch alot, with out changing the lite situation. Will watch and advise.


Turnpike.