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Message Center - Battery - AC does not work

irhutch

Full Member
Joined
Mar 31, 2010
Messages
10
Sound familiar to anyone?  Started up and the Battery light come on and the A/C did not work nor does mileage display. Could not find a fuse out, battery seems just fine and voltage shows it is charging. I disconnected the negative battery terminal while running, car still ran fine lights work and all. When I re attached the cable the message cleared. I started up, the A/C would now come on but shut down and battery light came back on.
 
How old is the battery
 
Have it checked by dealership...
could be system or alternator or ??
 
Did you find a fix yet?  My 02 Av is doing the same thing.  A few months ago my A/C controls quit and I found that when I pulled the fuse (not blown) and put it back in, it would come back on.  But now the message center lights, the A/C controls don't work, the 4WD buttons don't function and my mileage display only lights up during startup.  Pulling the fuse out and replacing no longer fixes the problem, but disconnecting the battery for a few minutes does............temporarily.
 
I am having the exact same problem. when i put the key in and turn it one click to ACC, everthing is just dandy. However, as soon as i turn the switch to run, the battery light displaces on the message center, the DIC is completely black, and my HVAC doesnt work at all. Now, with the key out, I can automatic start it and everything works PERFECT, but as soon as I insert the key and turn it to run, the same thing happens. I think this is the dreaded ignition switch problem. what does everyone else think??
 
As an update it never quit doing it, it finally got to the point that it would not re set itself, it is not the alternator or the battery, sometimes I could tap on the dash, work the shifter back and forth or tap on the inside fuse box with a screwdriver, the dash lights would flash off an you would hear some clicking then the system would reset itself and everything would be fine until it did it again.

This time I pulled the lower dash covers loosened then tightened the block behind the fuse panel. Everything reset and it remained working and still works now. However it did on one occasion do the same thing then reset itself without me doing anything so I  am not satisfied it is fixed. I am thinking it could be a bad connection where the block of wires connect to the back of the fuse panel, the ignition switch or the software for the dash panel. I have not been able to find find anything about the dash panel software but have heard that can be a problem.
 
Do you mean the large black connector that plugs into the rear of the left-side fuse panel (LBEC)?

My wife's 2005 Tahoe Z71 is experiencing similar issues. It will be fine, turn it off and then back on and the 'Service 4WD', ABS, BRAKE, indicators are all illuminated and the AC stops working. Upon further inspection the AC works (compressor engages) but the blower motor doesn't get power. The AC head unit is not getting 12vdc+ from the panel to switch the blower, instead I only see 1vdc+ when the truck is running and 0.085vdc+ when the ignition is in ACC. I moved back to the LBEC and found that all of the fuses in that panel were seeing the same sad switched voltage input, while the engine panel and battery were showing a steady 10-11vdc+. That makes me think that my issue (and the many similar ones I see reported on the various GMT800 forums are all the same, wiring or grounding issue with the LBEC. Did you see the same sort of conditions during your testing?

What is weird is the alternator works, start the truck and we get a nice 14.1vdc+ but the circuits don't come right. Without a full wiring diagram and systems operations manual for this damn thing I can only speculate but

During my diagnosis the battery died and had to be replaced, not shocked since it was five years old. After replacing the battery the truck came right -- sadly after a drive it went back to the same issues. At this point I'm certain it must be a wiring issue going into that panel, I looked under the dash and I don't see any worn wiring to cause shorts. I already checked the G110 and other related ground under the chassis -- they were caked with dirt but not corroded at all, cleaned and lightly sanded them just to be safe and re-torqued them to the frame, again to no change. I checked resistance to the engine block ground and alternator grounds to the battery, both read less than .5ohm which should be good.

Anyone have a picture/diagram of all of the grounding locations in these beasts? I'd happily ohm out each one just to clear grounding as an issue.

 
Isolated issue to a harness behind the LBEC. Once I've confirmed the issue, I'll post more, with pictures.
 
OrnyDuck it would be nice to have something else to try. I posted this in 2010 it still does it. Over time I have noticed different things, I have hit the dash with my palm and the dash lights would cycle on and off and something would reset then everything would work. I have lightly tapped on the inside fuse box with something and it reset. Lately neither of those will work but I can move my tilt wheel up and down a few times bumping it against the stop at the raised position and it will cycle back on. I have tried to find a loose connection but to no avail. I would just take it to the dealer but I had a different electrical problem when it was new, they replaced something but that was not it, I returned it and they replaced something else. Same problem came back a third time so I had no interest in being ripped again. 
 
I wonder if bad ignition switch as when it goes bad all sorts of strange things can happen
 
The ignition switch is one of the things I thought about but I hate just being a parts changer till something works. If it ever gets so it will not reset when I do things I guess I might have to do that. It seems to me that if it were the ignition switch was the problem lightly tapping the fuse box would not make it work. I left the column covers off last time I worked on it and tried tapping on the switch when it malfunctioned but that did not get it working.
 
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