First off I have a 94 S10 blazer with the 4.3 vortec and I have 193k on it. The problem that I am having is that when I attempt to put the vehicle in 4wd HI (push button) both the lights flash, I can hear the noise of it engaging but then both lights stay on (4hi and 4lo) I only use the 4wd to get through the snow and to get to the main road. I disengage it at the first stop light by shifting into nuteral (don't know if that's required but it's what I've always done). Sometimes it takes several attempts for the 4wd to even work and I am unclear if I am in 4hi or 4lo. It always disengages without a problem. How can I check if I'm in 4hi or 4lo? and does anybody have an idea on what i can do to fix this problem??

Thank you
Andre

 

You will know if you are in 4lo as your engine RPM will be much higher. 4hi will have the same RPM as when you are in 2wd for the same speed.

 

You need to replace your transfer case motor. There are several threads on here about it. The board is going bad and not working properly, i just had same problem on a 96 took about twenty min to change. Here is what i just changed mine with works like a charm now
http://shop.advanceautoparts.com/web...NAMS_754956202___


There are a few write ups on how to change it here is one i found on zr2usa another great site for info

http://www.zr2usa.com/mboard/index.p...=encoder+motor

 

Well there is no tachometer but I could just listen to the motor huh. I was playing around with it more the yesterday and when I hit the 4LO button it seems to always work but not the 4HI. Think that will still mean it's the transfer case motor? Thanks

 

The reason both lights are on is cause there is a little board inside the motor, that goes bad. It cant tell what gear (4hi or 4lo) it is really in. So it could very well be changing gears and the motor be fine but the little board in there is bad so it lights up both lights. I hope this make sence to you.

your truck should only go into 4lo when it is in newtral you could defently tell when your in 4lo cause u cant go very fast

 

ok great thank you for all the help.

 

had the same problem with my 94. Went to the junk yard to get another t-case and the guy told me my problem happens alot with these vehicles. he advised me to remove the main connecter going to the t-case and spray both ends with WD-40. Did this and no more problems with both lights being on and also it engages perfect each time. hope this helps

 

What if I take neg. post off battery and 4wheel hi works for half a day then stops?