99 Blazer 4x4 problem

[axendo80]

I reviewed all of the messages on this forum and have some hints as to what my problem is. But I just wanted to see if any there are any other ideas. When I hit the 4hi or 4lo button it continues to blink w/o becoming solid. I can hear a clicking sound and when I switch back to 2hi, I can hear and feel the 4x4 disengaging. I did try the idea of disconnecting the battery for a half hour, but it did not resolve the issue. I only use 4hi 3-5 times per year and have only switched to 4lo a couple of times to ensure it is still working. From reading other postings, it sounds like it may be the encoder motor. Is this a correct assessment? If so, what is the difficulty replacing it for a novice? I bought a Chilton book, but it does not mention the encoder motor anywhere.

Thanks in advance for any advise!

[BlazerLT]

So the problem has gone away now?

[Mudsock]

Shift to 2wd - jack up the front end (both tires off the ground) turn one of the front tires by hand - does the other tire turn? It may be that the 4wd is not fully disengaging.

Next, look for the transfer vacuum switch, it's on top of the xfer case just behind the front driveshaft with 3 vacuum hoses attached to the top. Pull the hoses off. Do you hear a vacuum release? You may also hear the front diff. disengaging. If so, it's probably the vacuum switch. Very easy to change (7/8 wrench is all you need) and MUCH less expensive than an encoder motor.

[axendo80]

No, when I press the 4hi or 4lo, the light still continues to blink. I rode around on the snow last week with the 4hi blinking and the truck appeared to be handling as if I was still in 2wd.

I now am afraid to engage the 4x4 after reading a posting that driveline could be damaged if the 2wd is not being re-engage properly. I would like to get this fixed before the next snow hits. We got hit hard last week with ice and snow and driving in 2wd really sucked.

Any thoughts?

[axendo80]

Thanks for the suggestions. I'll give them a try tomorrow and let you know.