I think you will all enjoy this one.

Here goes. I had to change my windscreen due to age (delamination). That all went well, ive been checking all electrics in the car following dash lights etc and some other issues. Went to check the wipers to ensure all was well on the new screen , and nothing. Ive judt started checking this out question. Is there anything comes to mind with anyone, before i progress further. As all was working before i changed the screen. Could be just coincidence. But does seem strange. Thanks in advance for your help. Redborderreivers.

Hi, I assume you have the Electrical Troubleshooting Manual?    I have the '78 version, your '79 may differ slightly as I believe the wiper control module (does it have the pulse-delay option?) may be different?

I've never had a screen out, but I'm guessing some manipulation of the dash, so possibly a wire off behind there from the wiper switch?  Or even in the engine bay, on the motor itself?   

But I suppose fuses first, then earths, then a wire trace ?

Thanks, ii have had a vacuum pipe off the light switch before, resulting in the light front flaps not returning to home as they are power return. Not spring as i had immagined. So thats the sort of issue i was wondering, if a vacuum pipe was off resulting in a switch not being made, holding off the supply to the motor. Anyway, thanks for that ill start checking through this week and update all when i find out what it is, thanks redbordereives

I don't want to sound like Captain Obvious here, but did you check the fuses?  Maybe while you were messing with the screen, something shorted the fuse?

Or, like was said above, maybe you clipped a wire that runs near it?

Maybe the switch itself got knocked around and wires came off that?

Hi, adam. Fuse ok. The guy i use for windscreens is A1. I use him all the time in the trade, windscreen was out and new one in at my premises i about an hour, theres no messing about  remove trims needed top  &side chrome retsining strips. Then back in after fitment of screen. Dash isnt touched.  But i need to look at the back of the switch for connections, but its easier for me to trace from the motor back over to see what supply im missing. To be honest i was hoping there was a vacuum switch related to the wipers, that i was not seeing andbthe supply was being held off. Ill checknout fully this week and updateon the forum, best regards, redbordrreivers

Do they take the dash apart to replace the windshield?

No. The t top chrome tee. The side chrome covers, the internal left and right plastic trim, wiper blades. Roughly thats all, the class sealing glue is then cut using a wire which is fed through using a windscreen tool, ( just like a narrow knife with a t handle on and a hole at the end for the cutting wire. Once the wire is through a back and forward motion cuts the old sealant, so the windscreen can be removed. The surfaces are then cleaned and new glue/sealant bead put around where the windscreen is to seat. The windscrean is then picked up from its stand using two suction cups and placed in postition on the car. The screen is held in place with masking tape for about four hpurs until sealant is cured.   Hope this helos ., best regards brian

First off, no vacuum involved in the wipers by 1979, and even the early car only had vac operated wiper "doors" (covers).

How did the screen fitter remove the wiper blades?   Just the blades or the whole arm?  Could they have dislodged a wire on the motor?  Did they re-fit them correctly?

Just a few things to think about!😄

thanks , ill look through methodically and see if anything has been dislodged, i am a retired time served turbine engineer and also been involved in the autotrade accident damaged repairs and rebuilds of classic cars for many years , although this is my first corvette, ive had it in the uk since 2009, brought it in from kansas,  

i just wanted to see if there was anything obvious that i should initially look for, ill go through the problem solving methodically as i said and when i find the issue no matter how simple it is ill report back to the forum, thanks for everyones help on this , it is greatly appreciated, regads, brian

I would start at the switch and check for 12 volts. If you don't have it at the switch, then you need to trace back to see where you're losing it. If you do have 12 volts at the switch and the switch is not 12 volts when it's closed, then you have a switch problem.  You'll need to check both the high and low speed outputs of the switch. If the switch is letting the 12 volts through, and you need to go to the motor to see if the 12 volts is getting to it.  If 12 volts is at the motor and it's not functioning, then you either have a bad contact at that connector or the motor is bad.