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On my '70 the windshield wipers wait about 30 seconds before the windshield wiper door opens and the wipers come on when you move the windshield wiper switch. If you use the bypass switch under the steering wheel the windshield wiper door opens immediately and if you turn on the windshield wiper switch the windshield wipers come on immediately. My question is what is causing the 30 second delay when you turn the windshield wipers on using the windshield wiper switch?
Not the problem, the wiper door doesn't open for about 30 seconds and then when it does the wipers come on immediately. The wiper door limit switch is working fine.
Vaccum leak. The normal vaccum circuit has a leak in it. If I had to guess I would say the relay right next to the brake master cylinder. Look at the vaccum diagram for the wiper door and follow it through.
That is a new vaccum relay and it seems to be working perfectly. The only part of the system that I haven't checked is the solenoid that is activated by the windshield wiper switch that is up under the dash. The solenoid makes a good strong click when you turn on the windshield wiper switch. The location of the switch is making it difficult to test.
I'd guess that your solenoid is either not shifting properly or you have a kink in the hose from that solenoid. It must be related to this circuit since your manual over ride system responds well.
That is a new vaccum relay and it seems to be working perfectly. The only part of the system that I haven't checked is the solenoid that is activated by the windshield wiper switch that is up under the dash. The solenoid makes a good strong click when you turn on the windshield wiper switch. The location of the switch is making it difficult to test.
I think that since the switch under the steering wheel works well and the one under the dash doesn't, points out that there is probably a problem with the one under the dash. Simply remove the dashboard and check this switch. (As I remember, there is a vacuum hose to this one also, which could be another source of leakage).
Since the wiper door opens when there is no vacuum on the control for the actuator relay, a kinked line would keep the door open all the time, so I don't think that is the problem. My guess at this time would be the solenoid is closeing slowly, thus causing the delay. But that solenoid is making a strong click when the windshield wiper switch is turned on. I've got to get the solenoid out of there some how. As Z-man stated I may have to take that side of the dash out, which I have done a few times. Does anyone know where I can get another solenoid if I can't fix this one? I looked in several catalogs and called a few of them and I haven't found anybody that sells them.
... Does anyone know where I can get another solenoid if I can't fix this one? I looked in several catalogs and called a few of them and I haven't found anybody that sells them.
Dr Rebuild used to have them. Is he out now? If you can't find a good one, consider a fan-clutch relay from an 18-wheeler type truck. You can get them at a dealership or NAPA.
The tech tip only mentions that this will cure a non-opening door but it will also cure a door that opens and closes or opens and stays open after you turn off your engine.
Since the wiper door opens when there is no vacuum on the control for the actuator relay, a kinked line would keep the door open all the time, so I don't think that is the problem. My guess at this time would be the solenoid is closeing slowly, thus causing the delay. But that solenoid is making a strong click when the windshield wiper switch is turned on. I've got to get the solenoid out of there some how. As Z-man stated I may have to take that side of the dash out, which I have done a few times. Does anyone know where I can get another solenoid if I can't fix this one? I looked in several catalogs and called a few of them and I haven't found anybody that sells them.
http://www.corvetteparts.com/ or Davies corvette is where I got mine. 49.75 plus shipping
part #331118 1968 - 1972 Solenoid, wiper door vacuum control valve $ 49.75