Will a bad transmission transfer case vacuum switch cause a battery parasitic draw ?? also no 4 wheel drive. Plan on changing it & all Vacuum hoses. But curious about battery draw from actuator switch??

 

The switch itself is likely to not be the true source of the draw, rather a symptom, as it should not be powered when the truck is off unless there is a fault in the TCCM (transfer case control module). If the switch does have power when the truck is off, then that would indicate that something is keeping the TCCM active after the key is turned off. There have been some pretty thorough explanations of how to perform parasitic draw testing in other threads in the past that you should be able to find.

As far as the no 4wd, it could be the switch or it could be many other things with the 4-button system I assume your trailblazer trimmed truck has. There are also some pretty in depth diagnostic threads on the NV236 transfer case that can be searched up (tech articles, etc.).

 

Swartikk thanks for the response. have had a parasitic draw on & off like intermittent gremlin's for awhile driving me nut's. I did have a chipmunk habitat going on and changed all my vacuum hoses. working on wires. now..