My 90' Astro EXT is like a deluxe cargo van has power features but not the excess fluff stuff. I have A/C, p/w, p/d, but where is the rear door switch so if the right barn door is opened it will trip my alarm ?

I can't believe that chevy wired up a power door lock but not a domelight switch, it should somewhere be there ?

on my 91 it is the knob that you turn to dim your cluster lights...just turn it to the right all the way. Is that what youre talking about?

Nope I'm referring to the door switch that when you open the RHS Barn door it will trigger the dome light.

I'm not sure about the older rear double door models but the new 3 door "dutch door" models didn't come with a switch to turn on the dome lights! I have no idea why they didn't want the dome light to come on when you open the back hatch or dutch doors, very strange and a pain in the butt.

I checked my 92 Astro with dual barn doors. The switch is located in the passenger side door, lower right side. It's a white, push button switch located within a black rubber grommet. It's pretty easy to find. My Astro is a CL model, not a cargo model.

I believe you are mistaken on the Astro with dutch doors not having a dome light switch. If you look at the left gas support rod you will see 2 wires coming out of it. Thats the dome light switch and it is screwed onto the rod of the gas strut. As far as I know it is not sold seperatly, you have to buy the whole strut. The one on the right is identical and it controls the door locks on the 2 small swing out doors so that you can only open them when the hatch is open. Not hard to replace just pop the plastic panel that holds the rear speaker in and you will see where the wire is plugged into the harness. If you want to verify this just take the 2 wires from the left strut and put them together and the lights should come on. The struts are a dealer item and run about $40.00 each. Hope this helps.