Soo, I was boonie bouncing yesterday and when I went to shift to 4HI, the the little light just flashed and never shifted, I eventually, after about 5 minutes or so, just clicked 2HI.

Any ideas?

P.S.
2001 GMC JIMMY

 

Quick update, fluids topped off still not shifting.
What's my next step, do I check the electric shift or the transfer case itself?

 

Need to know what transfer case you have, 3 or 4 button as they are different.

 

Four

 

Four.

 

Is it more likely to be the switch, the transfer case control module, or the transfer case itself?

 

My suggestion would be to remove the switch, carefully separate the two halves to expose the small circuit board and then reflow all the solder joints, especially on the connector pins. This worked for the 4 button TC in my '02; would not switch, lite would just flash. Takes all of 20 minutes and does not cost anything.

Second suggestion is to check and clean the contacts of the Transfer Control Module (TCM). Also quick to do and does not cost anything.

Third would be the check all the vacuum lines under the hood. If you have not replaced these, then they are leaking. Takes a bit longer to do and does cost a few $$ to buy the hose. Also helps if there is any HVAC problems.

Let me know.

 

Thank you LannyL81, I'll check those and get back.
I appreciate the starting point, my other blazer, the 96, has the the shifter on the hump so the electronic shift is new to me

 

Odd....your '96 has the shifter on the hump? I had a '95 and it had the three button electronic or "shift on the fly" feature. I thought all of the '95 to '04 Blazers had this.

Anyways just be careful of the plastic switch housing, rather fragile.

 

LannyL81, yeah found that out, Thankfully summit has the switch for 20 bucks from dorman.

Yup, from what I've heard the floor shift and the large factory flares are rare