98 Z71 4WD Problems - button lights

[98Z]

My truck started messing up on me today. I noticed that the amber LED in the buttons for the 4WD weren't on. So I pressed the 2WD button. Nothing happened. I pressed the 4WD button, nothing happens. I put it in nuetral and press a button and the two LEDs on the 4HI/4LO button both flash for a few seconds and then they go out.

What went wrong with my truck? Anyone?
Is this going to be expensive?

Please help me.

[Blue Bowtie]

With the engine off and transmission in PARK, turn the ignition ON while monitoring the indicator lights. Do they all flash once? They should all blink once to indicate a power-up test completion of the TCCM. The ignition has to be off for 6-10 seconds between cycles to force the TCCM to run the self test again.

After blinking once, one of the lamps should turn on and remain on, indicating the current range/position of the transfer case.

[MT-2500]

Does it have a 243 or 246 transfer case?
Does the shift buttons have a auto button or just 2W -4W high - and 4W low?
Is 4 wheel still working?
Does it shift to 4W low and 4w high?

[98Z]

Blue Bowtie:
It does just as you describe (like always), but then NONE of the lights stay on after that. Everything is off.

MT-2500:
Does it have a 243 or 246 transfer case?
I really have no clue on this one

Does the shift buttons have a auto button or just 2W -4W high - and 4W low?
2W, 4Hi & 4Lo

Is 4 wheel still working?
It was in 4 wheel when it messed up. I was able to shift it to 2 wheel by putting the truck in nuetral and playing around with the buttons.

Does it shift to 4W low and 4w high?
Not anymore. When I press a button, nothing happens. If I put the truck in nuetral and push the 4Hi button, both LEDs for the 4Hi & 4Lo will blink a few times, and then they go out again. None of the three LEDs on the buttons are staying on under normal operation, but they do blink during self test at startup.

I was doing some searching (I know, wonderful tool) after I had posted this and found this thread...

http://www.automotiveforums.com/vbul...d.php?t=692443

Think this is the same problem I'm having? If so, it sounds like a simple fix.

Thanks for the responses guys.

[MT-2500]

That TSB is for a 246 transfer case.
Check your tag on transfer case but I think you have a 243 case.
If so you can ground pin 13 on your diagnostic connector and get codes.
Watch shift lights and count flashes.
Post back any codes you get.

[skipr]

Originally Posted by MT-2500

That TSB is for a 246 transfer case.
Check your tag on transfer case but I think you have a 243 case.
If so you can ground pin 13 on your diagnostic connector and get codes.
Watch shift lights and count flashes.
Post back any codes you get.

I don't believe that works on 1996 and newer Generation 2 ECM's. Must have a scan tool. It may be useless unless the on board computer indicates a problem (SES light or service 4wd light). Have someone switch the 4wd in neutal while you tapp on the actuator with something fairly heavy (like a hammer) but don't beat the hell out of it.

[MT-2500]

skipr
You need to get the good book out and read it.
On a 243 transfer case you can pull transfer codes by grounding pin 13.
On a 246 transfer case you need a scan tool to pull codes.

[JaVeRo]

I found this out on my wifes S10 with the 233 transfer case. I checked the Haynes book on my 96 and it works similar on the 243 transfer case.

The Transfer case control module has an error counter that is increased by 4 each time something doesn't work right and decreased by one each time something does work right. If it reaches 32 then it sets Diagnostic Trouble Code 2 and reverts to a "default rail to rail shift pattern in which only shifts into 2HI and 4LO are possible" (quoted from the book, I have no idea what it's talking about).

To clear the code you can pull the 20 amp Tranfer Case fuse for a minimum of 2 1/2 minutes. Cycle the key on and off 5 times. This doesn't solve your problem but may get you out of a bind.

Grounding pin 13 on the Data Link Connector (DLC) does give you the codes on a 96. I would think the 98 would be similar. The pins are top row left to right 1 - 8, bottom row left to right 9 - 16.

I'm just glad my 96 has a floor shifter.

James

[highhopesforcars]

I have had this problem before on my 2000 and 99. Ith the 2000 the lights worked but it would not shift that was the acuator on the case sticking . On the 99 the Lights would just go out and not work with out much playing around. Had to change the whole swith panel one the dash