I need some help figuring out some issues with a C3
Hello everyone. Someone asked me to take a look at their convertible Corvette C3, saying the windows are not closing fully and the windshield wiper cover and wipers don't work at all. They also mentioned that it works absolutely fine sometimes whilst driving, but only from time to time. I'm not a mechanic, just a car enthusiast with some experience working on my BMW E46. With Corvettes, and especially old ones being extremely rare in Europe, I took the chance and agreed to help. It turned out however, that it's not as easy to find the sources as I thought.
With the info I had from the owner, I was 99% sure it's an electrical fault since neither the cover nor the wipers showed any sign of life when toggling the switch. I found somewhere online that the black wire between the 2 blue ones going to the switch, is the ground, so I went ahead and tested the voltages. When comparing between either blue wire and the black wire, there was 0 voltage. But when compared with the battery negative it showed 12 volts. Also, there was no continuity between the black wire and the battery. This led to me assuming the ground is interrupted, so I bridged that wire directly to the negative of the battery and tried again. Nothing changed and the system was still not working, so I went ahead and started looking in the engine bay, where I did a few bizarre discoveries. First of all, there is a disconnect wire just hanging around and I can't find out where it belongs (see fotos). 2nd of all, there is this hose going out of what seems to be the wiper motor and into nowhere (see fotos). I've red online that the cover is vacuum actuated so it might have something to do with this.
I'd like to ask for some advice where too look next, or maybe someone here knows what could be causing this. Also, where should I look first when checking out the windows not closing fully?
Thanks a lot in advance!