It plugs into the vacuum pump motor that attaches on the front of the large brake booster diaphragm housing. If you have vacuum assist option.

 

 

what is this pic of? The plug for vac assist? What are you implying with it? Just did this swap tonight and realized I was going to have to do something about the vac assist plug as well. Thanks OP for doing all the leg work and making this a quickie. Had the PS pump already on the engine I just built and dropped in so it was basically a 1 hour job minus figuring out how to keep the idiot light off. Think I'll just clip the plug where it t's off the harness, crimp and heat shrink the black and blue together then heat shrink the others and tape them up inside the harness loom & stash the plug incase I need to use it in the future. Then no dongle looking **** flopping around under this hood! Also happen to have a set of dual piston suburban calipers and rotors laying around for the swap. Should stop quite well.

 

This was my way of faking out the light. I didn't want to splice or tee into the original wiring so I bought the connector and jumped it that way.

 

Gotta ya. Seams I was having trouble reading and writing last night. I like the idea and it seams like less work. Where did you get the commcector?

 

eBay