Those actuators do not take much vacum to work shown when I had the battery tray out to look at it and could make it work by dissconnecting it at the first T and sucking on the line. Old school yes and keep the filth in your heads

 

Yes when i bypassed the vacuum switch I pressed the 4 hi button and it kept flashing. But I backed up 1-2 feet and it went solid and stayed solid..and I got the new switch yesterday and installed it and everything works fine!!

 

Where is the switch exactly ive been working on mine and i couldnt find the lines everyone keeps talking about next to the windshield wiper motor, if someone doesnt mind could yall post a picture of it please?

 

It's rite in the middle of the firewall. I'll try to take a pic later or I'm sure some else will post it

 

95SlS, your truck may not have that switch. Charder has a blazer with the 4 button switch in the dash (NP8 transfer case). If you have only 3 buttons (NP1 transfer case) on your 4x4 selector switch in the dash, I dont think you will find this switch on the firewall; however, since you have had 4x4 issues have you noticed that your heat or AC will only blow through the dash vents? If so, there is vacuum switch located on top of the transfer case at the front of the truck and it has three vacuum lines that run to it. Often times the seal on these fail and allow transfer case fluid to be drawn into the vacuum which disables the 4x4 and vacuum operated hvac controls. Also, there is a vacuum actuator located under the battery, but if you have already checked that and you are leaning towards a vacuum related issue, I would pull the switch on the transfer case and check for fluid in those three lines. Just a thought, hope this helps.

 

Yes i did actually notice that right when i got my uncle to take a look at mine. there was a GIANT hole in the vacuum line so i replaced all the brittle dry rotted ones so everything is good now

 

hello,

#1. my tcase switch went bad.. that was replaced along with the acuator and it seems like my 4wd works now however the heat/air only blows through the windshield defrost or the dash vents (wont blow towards feet only, even if the vent switch is set to feet)... how can i fix this so that the air will blow towards my feet as well?

#2. i have the 4wd push button switch in the center of the dash... sometimes when im in any of the settings (2w, 4wh, 4wl) and the circle light is on it will turn off completely... does this mean anything or is it just the light turning on/off bad contact or something? it doesnt blink... it will just turn off... sometimes if i bang it hard enough it will turn back on for some time.

thanks.

 

so where is this vacuum at cuz i hit the button (3 buttons it has i guess) and it does nothing but i can do 4 lo

 

Well I know I am a little late to the playing field but I spent the better part of an hour for the 3rd day and was considering acquiring the by-pass kit for the 4wd when I was attempting to disconnect the actuator cable from the actuator bracket below the battery when I noticed a "Whooshing" sound from the back of the block. It just did not sound like that was supposed to be that way. I traced the line back from the switch on the firewall and found there was a rub through to the top hose and replaced it and it worked. Just to let you guys and gals know the line necks down with the line from the actuator and you have to be careful of pulling it apart or put a 3/16 line inside a 3/8 line to make it work.

 

Ditto on mine, always same place with everone, or so it seems. If I knew how and it was OK in forum rules I would like to drop that tidbit it in one of the threads like "4x4 no worky".