I can't figure these things out yet! The only way to open the wiper door on my '71 is to pull the manual switch under the steering column. The wiper switch clicks at the wiper motor, but it won't open the door. Once the door is opened manually, the only way to engage the wipers is to push and hold the wiper/washer switch. Any experts out there who understand these things?

 

You have touched upon one of the most troublesome areas of the Corvette world the dreaded Headlight / wiper vaccum system. If you goggle Corvette headlight and wiper system you will come accross endless conversation and article on troubleshooting. Here is one which should help your particular problem-http://www.corvettefaq.com/c3/wiperdoor.htm

This system is complicated but once you figure it out it is relatively easy to diagnose problems.

 

Thanks! This should keep me busy for a while.

 

had similar problems with my early '71,learned a lot the hard way.if you can open door with pull down switch,it means you have at least some vacuum to system,i strongly suspect the little vacuum switch in wiper compartment located on pass.side.if this is defective,wipers won't operate.the reason they work when you hold wash position is a different function of wiper motor itself..good luck jc