That bulb won't get hot enough to melt anything let alone a circuit board.

Do yourself a favor and buy a replacement switch panel and put it in. It will save you time, $ and frustration in the long run.

 

Well, it appears the plastic tab that pushes on the button has melted so they won't push the buttons far enough to activate.

It is working fine now. I will save myself 100$ until I get frustrated.

Thank you

 

I have a somewhat similar issue, BUT my normal 60/40 AWD is working but when I try 4 hi lock the button does not blink, nor does 4 hi lock engage. No CEL on or anything. Any thread suggestions or advice on any of our issues? 4 Lo works just fine. 4 hi is the only one not working. No idea. If the transfer case motor is bad would it still make it to 4 Lo just fine? I may try what IllusionX did. Way to go finding the problem. I hope that is what happened to mine, instead of something more serious.

 

Translation: you are on your own.

 

Tainter is right and replacing that board is good advice... there is no way those bulbs are capable of melting anything unless there is a larger electrical problem occurring. As far as the functionality of the different 4WD Lock modes, I suspect that your control panel looks like this (or at least it did before you took it apart... ):






If this is the case, then head over to Hummerdotcom and go to the Owner Resources page (Vehicle Owner?s Manuals | HUMMER). Grab a copy of the Owners Manual and the Getting To Know Guide. That button you were asking about on the right hand side is your rear differential lock... it can only be engaged once the vehicle is in 4 Lo Lock. As far as what state of motion the vehicle needs to be in prior to engaging any of those modes, it is detailed in both the Manual and the Guide:

 

You, sir, are a useless addition to this forum. Please sell your hummer, and then move along to another forum.

@ the OP: as has been stated, those tiny LEDs dont get hot enough to melt anything. If your circuit board/buttons have melted then you have an electrical problem elsewhere in that circuit. If your dash is still taken apart, try tracing all the wires going into that circuit board and see if you can find a short or frayed/damaged wire that might be causing a problem. Could be something you can fix with some electrical tape.

Good luck, let us know what happens.

 

I would guess (and I emphasize GUESS) that your problem is somewhere in the circuit board or button for the 4HI Lock...I would think that if you had the plastic shift fork failure that you wouldn't be able to get into 4Lo. Since you can get into 4Lo and back to 4Hi (if I understood your post correctly) then obviously your Tcase is shifing properly. I would begin by looking at the circuit board like the OP did, perhaps the button for the 4Hi lock isnt engaging the circuit board properly.

Good Luck

 

Actually, the circuit board lights are NOT LEDs. When I took that apart, they were actual incandescent bulbs that get pretty hot when lit for a period of time. So my plastic keys indeed melt and are not actually pushing the buttons on the board.
Eitherway, it is fixed for me, and works.

For the record, if anyone having issues with any of their buttons, either the button on the board has broken down, or the plastic keys are not able to push far down anymore to push the button on the circuit board. Testing it taken apart like I did will confirm the problem.