1999 Chevy Blazer 4 wd Problems

Beth

1999 Chevy Blazer 4 wd Problems

Unread post by Beth » Sun Dec 13, 2009 11:20 pm

1999 Chevy Blazer
4.3 vortech
My Blazer has push-button 4WD. During normal driving the 2-Hi indicator is lit. However in recent weeks I've noticed that this light is going off for short periods of time. It eventually comes back on, but I'm worried there may be a problem with my transmission. Any ideas what might be causing this? Thanks so much for your help!

Meccboy

Re: 1999 Chevy Blazer 4 wd Problems

Unread post by Meccboy » Sun Dec 13, 2009 11:22 pm

Well, first off. This would not be atransmission problem. This is only related to the 4 wd. transfer case.
There are three common failures. Listed from most common and inepensive, to most expensive...

1. The actual 4 wheel drive switch in the dash. If the lights are acting up but no change in the truck actually being in 2 or 4 wd, most times it is a faulty switch.
2. The tranfer case control module is acting up. This can also cause this lighting problem. It is located under the pasenger side of then dash. Have had a few go bad, and also a few go bad becasue they got water in the electrical connector. Unplug the module and look for green corrosion on the terminals.
3. The "Encoder Motor" This usually causes problem when trying to shift in and out of 4 wheel high or low. A faulty encoder would casue it to not change gears, and would also set computer codes in the module.

Beth

Re: 1999 Chevy Blazer 4 wd Problems

Unread post by Beth » Sun Dec 13, 2009 11:22 pm

How would I be able to tell if the truck is in 2-wheel or 4-wheel drive to know if it is a faulty switch? I just go off the indicator lights so I’m not sure how to tell without them.

I tried shifting into the various gears in my driveway a few nights ago and I could hear and feel things switching so would that indicate that the Encoder Motor is ok? I used 4-WD about a week ago to get out of some mudd and it appeared to be working then too, I think I used the auto button though and not the 4-hi or low buttons. The light was going out prior to that.

jimmy01

4wheel drive

Unread post by jimmy01 » Wed Dec 23, 2009 1:01 pm

my 2000 chevy blazer doesnot go in to 4wheel drive,4hi light blinks,it willnot go in 4lo or auto4wd. thank you

Guest

Re: 4wheel drive

Unread post by Guest » Wed Dec 23, 2009 8:21 pm

With the lights blinking, it could could be a problem with a few things.
Could just be a switch problem, could be the actuator, or possibly the 4wd control module.
Have seen a few of these modules get corroded connectors from water getting into them.
The module is located at the passenger side floor board in the truck. behind that side panel down by your feet.
just unplug it and look for green terminals.

MeMo

Re: 4wheel drive

Unread post by MeMo » Wed Feb 17, 2010 10:12 pm

Guest wrote:With the lights blinking, it could could be a problem with a few things.
Could just be a switch problem, could be the actuator, or possibly the 4wd control module.
Have seen a few of these modules get corroded connectors from water getting into them.
The module is located at the passenger side floor board in the truck. behind that side panel down by your feet.
just unplug it and look for green terminals.
Have had several modules like that.
Also the actuator on the front differential or encoder motor on the transfer case if you have that style.

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