Heres what happened…removed my ac compressor. installed bypass pulley. drove van around town no problem came home. hour or so later…got in van, started van…pulled light switch on, van died immediately. No lights came on. Van won’t start…did start once but died withing 3 seconds. no visible wires bad that I can see. radio is reset, and the screen is jumbled. I have no lights, even my side mirror adjusting switch wont work. When I turn the key, seems normal…check light comes on, then goes off. I have brake lights, back up lights, no horn. I noticed the dash lights on. Pulled out buzzer from fuse block and lights go out. I replace the headlight switch, and the 5 am cluster fuse. dash lights out now. No start, no headlights. What the F…
Check and see if the battery is dead. Older battery’s can be fine one minute, and give up the ghost the next.
Where are the refrigerant lines that were connected to the compressor? Was the belt tight enough that the power steering pump didn’t squeal when the wheel was turned. It sure sounds like the battery is dead for some reason.
Coincidence is the worst enemy of diagnosis. Tester is either right or has the right idea. You either have a bad battery or a bad battery side positive connection or bad starter connection. You can check for each looking for a loose connection (if you can turn either battery terminal by hand, for example, it is too loose). Also you should look for the formation of a white powder on the positive battery terminal.
The negative battery terminal also needs to be very tight, although if loose it will not accumulate corrosive gas from the battery as will the positive lead.
Using a wire brush, first clean and then tighten both the negative and positive battery terminals. The positive cable that feeds into the positive battery terminal may need cleaning as well. You might find powder on the copper wires that contact the terminal, and this powder must be brushed off to insure a good connection.
The least likely problem is the second thing, that you just have a loose positive connection to the starter. In this case you would just make sure the connection is tight, and tighten it if it is loose.
One of the nastiest vehicles GM ever made in regards to getting things done in the engine compartment.