4HI 4LOW switch flashing

I'm a newbie here, so sorry if i didn't do this right.
I have a 96 blazer LS , 4wd, 4.3. I had probs with fuel level sending so I removed the tank, removed and replaced sending unit, and reinstalled tank.
Now the 4HI/4LOW switch on the dash is flashing and 4HI/4LOW does'nt work. Checked fueses, no probs.
What does it mean when the 4HI/4LOW switch flashes, and how could it be related to my replacement of the sending unit?? Any feedback would be much appreciated. Thank you for your time.

Check your vacuum actuator and make it has proper vacuum and check your transfer case encoding motor.

thanks blazerLT for your prompt reply. I took your advice and checked both. after manually working the actuater diaphragm, the switch lights no longer flash and i have 4WD again so i think i need to replace the actuater. thanks again.
While i have your attention i'd like to ask another ?:
How do i replace the No.3 spark plug?!? the steering shaft passes right in front of it, right next to the block. I refuse to believe i have to take the steering assembly apart just to change a plug! I thought changeing the plugs on my 89 jimmy was tough,...this sucks. THANKS AGAIN FOR YOUR TIME BLAZERLT.

thanks blazerLT for your prompt reply. I took your advice and checked both. after manually working the actuater diaphragm, the switch lights no longer flash and i have 4WD again so i think i need to replace the actuater. thanks again.
While i have your attention i'd like to ask another ?:
How do i replace the No.3 spark plug?!? the steering shaft passes right in front of it, right next to the block. I refuse to believe i have to take the steering assembly apart just to change a plug! I thought changeing the plugs on my 89 jimmy was tough,...this sucks. THANKS AGAIN FOR YOUR TIME BLAZERLT.

All you need to do is go through the wheel well with two long extensions a flexible joint and the plug socket.

You will probably have to hand screw the plug in a couple threads first.

And glad to help you, at least someone here appreciates what I try to do for you.

thanks for your advice on changing No3 plug BLAZERLT, I'll have another go at it.

You are very welcome.

eh we all appreciate the time and effort you put into the forums BlazerLT, it's just you come off harsh sometimes and that's frightening to a non blazer expert ;)

eh we all appreciate the time and effort you put into the forums BlazerLT, it's just you come off harsh sometimes and that's frightening to a non blazer expert ;)

I know......

I have been keeping it quiet, but I have quit smoking a month ago and that on top of my mom going into surgery for a brain aneurysm has put me on edge lately.

Ouch BlazerLT... Sorry to hear that man... Hope she pulls through alright!

Ouch BlazerLT... Sorry to hear that man... Hope she pulls through alright!

Thanks for understanding. :)

I am having a similiar problem. My 4x4 lights keep flashing and I can hear the TCCM Clicking off and on at the same speed as the lights. It starts out slow, then speeds up very fast. The TCCM keeps clicking even when the key is off. The only way to get it to stop is by taking out the TCCM fuse. I did the 12-pin test. I only get a code-1 reading. While doing the 12-pin test the TCCM does not click. Do you think I need a new transfer case motor?

Thanks in advance for all of your help!

Shawn

Sorry, just finished reading the rest of the replies from the thread. I hope your mother recovered well and is feeling better. My step father went through the same procedure a few years ago. He is well now, but the recovering can be rough.

I just reset the TCCM by disconnecting the battery for 10 mins. Now when I do the 12-pin test I get a Code- 3. Pretty sure I need to replace the transfer case motor. I just don't want to spend $200 and have it be the wrong part. What do you think?

Thanks Again!

Shawn

Yeppers, code 3 is a motor fault logged by the TCCM. Sorry :(