So I went to pick n pull and found not only a '93 Custom but a '93 Limited like mine as well. So I removed the glove box and the wood trim below it. Then the bottom black piece. You can remove the padded center trim, but that involves more removal of bezels. It isn't necessary. I did remove it at the yard but did not on my car. There are 2 screws holding in the controller. One electrical connection at the top behind the glove box area, and one on the bottom. Remove the arm from the bottom as well. It comes out through the bottom with some wiggling. At the yard I cut the colored vac lines that go to the unit 6" away from it. At home on mine I undid the neg battery cable and started in. I verified that I had vac at the connection behind the glov box where the black line connects to the pink line. I opened up the new controller and removed the colored vac line unit from the controller. Inside is a strip of the vac lines that slide onto solenoids. That goes to the circle of vac lines on the outside. I could not detach the lines on the outer portion from the inner portion on the one from the one I just got so I opened up the old one from my car and detached the lines from the solenoid and attached it to the usd one. I put it all back together and no luck blowing through the dash. So I looked and the vac line bundle I removed and blew through the pink line and could easily feel it go out the end that attaches to the solenoid side. Next I detached my car'* black to pink line higher in the dash and tried blowing through and no air came out. So I cut the pink line below the connector that joins the black and pink lines to get the connector out of the equation and still no air flow. That meant it was clogged at the round portion that is r gained by the nut or in the bar that connects to the solenoid. So I cut the pink line between the bar and the round connector and I could blow through the bar portion of the pink line but not the circular portion. I undid the nut that retains the rubber unit on and pried it apart. (Interesting note, the piece from my car had a slit where I could fit in a flat head to help push the clear rubber side away from the rest of the connector but the yard piece did not) once apart I took a large sewing needle and reamed out the black rubber nipple for the pink line. Eventually I could blow through it from the bar side of the pink vac line. So I connected it all back together after checking the other black nipples while I was at it and hooked it all back up and still no luck through the dash. So I bypassed that whole connector/ black nipple and clear rubber stuff and went from my cut by the bar straight to the glove box connector. I used a short piece of the pink line to slide into the glove box transition where it goes to the black line, and used 7/64" from autozone for the rest. Luckily there is a place by the upper connection in the controller'* box to fit the larger black tube through. I put it at together after checking that I had a vac to the bar with the car running and it all worked like it is supposed to. $5 worth of tubing. No glue, no heat shrink...just a troubleshooting mind and about 3 hours of time at home. To do it all again would be 10 min to take the dash apart, 3 to get the controller out, 10 to verify and cut and patch, and then 20 to test and put it back together.