When I turn the key to run, before starting the truck, all the dash lights come on presumably in a test. I believe the ones in the green circles don't come on because I don't ACE or Leveling but the ones in the red circles don't come on and my 04 does have a diff lock, and of course I have Low gear so the neutral position should have an indicator. Neither of these lights come on when I use those features either. And when I lock the diff I do not get the three beeps. I've confirmed both of these things function, the truck crabs and scrubs the tires during full-lock turns and of course driving in Low is easy to tell. My question is; assuming these lamps are bad, how hard is it to take the cluster out and change them? I think there may also be a switch issue on the diff lock because I don't get the beeping, but are these things I should be worrying about?



Edit: I just did some more reading and the manual states "Illuminates for 3 seconds as a bulb check when the starter switch is turned to position ‘II’." for all the items where this occurs and it does NOT state this for the two lamps in question. So, them not coming on at start up isn't relevant but them not coming on when I use those functions still is.

 

My diff lock lights only come on when I engage diff lock. The gears only come on when you take truck out of hi or low. The side to side light comes on when I turn the key on and then goes off. The other lights don't come on unless your truck is equipped with air bags

 

I like the way your fuel gauge matches the diagram...lol.

 

Spot on! lol

 

You guys are a riot. Bet ya didn't notice the tach and speedo are at zero too! Wait till you see the temp gauge...

So, I went to the yard yesterday and disassembled the binnacle on an 03 to see what made the dash lights tick. It appears there are no replaceable "lamps", but more likely LEDs soldered to the cluster's backplane PCB. I'm now thinking that this must be a switch issue because when in Low the Mode button still illuminates the S in the cluster and not the M. The ECU must not know that it's in Low and therefore no dash lights either. The CDL lever was so stuck that it doesn't surprise me that the switch isn't operating.

 

Old post but I have the exact same issue. What was the fix?

 

In my case the problem was the diff switches. I jumped them out with a manual switch in the console for Low and Diff Lock and the dash lights work correctly whenever I engage the switches.

 

So the switches only turn the lights on?

 

No, the switches are connected to the wiring harness and are providing the same ground signal to the SLABS ECU that the diff switches normally would. Whenever I select Low or lock the diff I press the appropriate switch, this enables HDC and also takes care of illuminating the lights in the cluster. It was easier to make this little adapter out of a parts truck harness and plug it inline to the connector that carries the ground signals to and from the diff switches than it was to change the actual switches in the TC. Plus it was about $200 cheaper than buying all new switches. If I ever drop the TC I may put new switches in it, but for now this kludge is good enough for me. In any event, bad switches were why the dash lights weren't coming on in my truck.

 

Ahh, ok. Pretty cool set up. I am guessing switches are the culprit on mine and have not had the console out to check.