1995 blazer auto 4 wheel drive won't engage

My four wheel drive won't engage. First the vacuum line to the front actuator had no vacuum, so my mechanic ran a new line to a different location to get vacuum. It worked for a while but now it doesn't, and the 2 wheel hi light doesn't light up either.

Check all vacuum lines.

If one leaks, they all will lose their vacuum.

The 2 wheel drive light doesn't work. Does it go into 2 wheel drive? Could just be the bulb in the switch. Since that one stays on the most, it burns out first.

Right you are, the 2 Hi bulb was out. I replaced it and now I can hear the rear transaxle switch engage. The 4x4 still didn't work so I checked the actuator under the battery. Sure enough, the diaphram is torn. I also found transmission fluid in the actuator; should that be there? My local parts dealer says the actuator is a "dealer only" part, so I have to wait until tomorrow to replace it.

Meanwhile the 1/2 inch vacuum line attached to the "ball" canister is broken off and I can't find where it goes. It's about 2.5 feet long. One thing I know it does is supply vacuum to the hjeater control switch (when it is hooked up properly) It needs to be attached to vacuum supply somewhere; any ideas?

To start, take care of the fluid problem first or the new actuator won't last. This can take out heater controls also. The fluid is coming from the vacuum switch on top of the transfer case (three port). Replace it. Next, all the vacuum lines will have to be flushed or replaced.

I believe that the vacuum hose goes to the rear of the upper intake manifold above the distributor.

Thanks, Rickza.......I found the port right where you suggested! Life is good!

Rickza,

The vacuum connected to my front actuator was not working, so my mechanic tapped into another vacuum line that provides constant vacuum. I'm wondering if that will work. If not, where should the vacuum line from the actuator (under the battery) come from?

From the transfer case vacuum switch, ohh by the way that is where you trans fluid is coming from also. Replace the vacuum switch on the transfer case

Thanks for the "vacuum line" tour. I now have vacuum to the actuator when 4x4 is engaged. This forum is super!

I am happy for you nice to see somthing get fixed