Hi, Ive got a 97 LS with the NON auto transfer case. Here's my dillemma (and yes I did search and read the do-it-yourself topics) 2wd and 4lo work fine but 4hi doesnt work at all. 4lo on occasion will not light the light but still engages. 4hi will not even blink unless you are in nuetral and then reverts back to 2wd. We just got our first dose of snow/sleet I was very disappointed to have to drive in 2wd. I think it may be the encoder motor but really have no clue.

 

This link should tell you all you need to know: https://blazerforum.com/fb.asp?m=56175

 

I had read that already the last paragraph states


Hope this helps, but If the thing is shifting (with or without a clunk) it won't have any codes stored...it disables mode shifting if a code sets...until the battery is disconnected for at least 3 minutes.

Mine is shifting into 4lo but not 4hi, so by that guide it shouldn't have any codes stored. I will run the diagnostic on it to be certain, but if he's right, it won't tell me anything.

 

I'm sorry..I made a mistake when I wrote that..it should sayif it is shifting from 2HI to 4HI then there aren't any codes. The TCCM does NOT disable4LO shifting when a DTC sets...only 4HI. If you continue reading in that paragraph....I did state that it disables MODE shifting (2HI to 4HI) and not RANGE shifting (2 or 4HI to 4LO). You have a DTC set that's why it will shift to and from 4LO and not 4 HI.

 

OK, well thats a little more clear. Any idea which pin is ground on the ALDL? I understand grounding 13 displays the code, but I dont know which is ground. Im going to do it like my Camaro with the paper clip trick, or at least thats I thought I was doing it. I can get a ground, its just easier to get ground from the plug.

 

Here ya go:


[IMG]local://upfiles/667/7131662E663E46E48953096DCDBE01FF.gif[/IMG]

 

Thanks, if I read that right, jumping 13 and the one directly above it will ground it and display the codes, paper clip will work perfectly in this case.

 

Small update, took advantage of the unusally warm weather and grabbed the codes from jumping pin 13. Unfortunatly there were none. Lights all lit, but then went out and did not flash. I tried jumping pin 13 to pin 5 and pin 4 with the same results each time. So for ha-ha's I turned the ignition to run 5 times without the pins jumped and the started the truck. 4hi works now. With the door open, you can hear the xfer case shift into 4hi, 4lo and 2hi. I need to press 4hi twice going from 2hi but it does go on the second press. All other combos only require one press of the button even 4hi->2hi, only 2hi->4hi takes two presses.

Now watch next snowfall we get, it's not going to work again. Im hoping against hope that it isnt temperature related.