where dose the vacuum under the battery come from
Check the gasket between the throttle body and the intake manifold. It may be blown out and creating a large vacuum leak causing the fast idle.
You can find a diagram for the vacuum system in a 1995 Blazer 4x4 will be located in the Blazer service manual. The manual can be purchased in most auto parts.
Mazdatruckin.com has a schematic for the B2600i vacuum lines in their tech section, it includes 4wd and cruise control devices. See the attached links below.
Haynes repair manuals have good vacuum diagrams
The 2001 Chevy Blazer vacuum switch solenoid can be found on the firewall in the engine compartment. The vacuum switch solenoid will be on the passenger side of the firewall.
It does not have one.
You can find a detailed vacuum hose schematic for a 1984 Oldsmobile Cutlass Supreme in the car's owner's manual. You can also check with local auto stores.
Need to know the location of the vacuum leak in order to answer this.
If the vacuum line diagram is not on a decal under the hood, or, if you don't know anyone with a similar vehicle that you can compare with, try your local public library's reference section on vehicle repair. Reference books are not available for checkout, but you can make copies to take home with you for reference.
Get manual specific to that vehicle and follow vacuum routings
Vacuum pump? Is this a diesel?
Start with a visual, inspect all vacuum lines for problems.
Yes as long as its free
It is important to have a diagram when making any changes to a car. For this car a free vacuum diagram can be obtained through asking an auto part store technician for a print out of the schematic.
The vacuum actuator is either in the fender or under the battery. The actually diff actuator is on the back/bottom of the front diff. Mine (2000 blazer) is under the battery. It sucks to get to. If you check the actuator and it doesn't move at all, check the vacuum, if it's not getting vacuum, check the switch on the top driver's side of the transfer case. It sends vacuum to the actuator. It has three vacuum hoses coming off of it. It costs fifteen dollars at autozone and usually greatly improves the performance of the acuator.
Under your battery tray
on the front axel
Need more information.
The engine's vacuum is mostly controlled by the cam. You can use a milder cam to increase vacuum, or purchase an inexpensive vacuum reservoir to make better use of the vacuum you have.
Check for vacuum leaks.
Check the 96 Blazer for any vacuum leaks in the system. A vacuum leak can cause the air flow to only come out of the heat vent.