If the entire grid isn't working, it's obviously a problem somewhere between the grid itself and the car's wiring harness. If portions of the grid aren't working, it's usually due to a break in one or more runs (usually caused by scratching the glass while cleaning it or storing something on the rear parcel shelf). Simple enough to fix... just warm up the glass with a hair dryer, apply Scotch tape to either side of the grid line where the break is, and apply the copper paste compound. Remove tape when fully dry and test.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Randy Ferrill Sent: October-21-09 7:38 AM To: Air-Cooled Volkswagen Discussion List Subject: Re: [vintagvw] Rear window defroster wiring I would think that if it was not an open circuit, that would be my first test. Does the wiring (paint) lose resistance over time? Bert Knupp wrote: > Mike, > > You're right. I found an old German manual showing a photo of the metal-can > relay under the left end of the rear seat. It's a continuous-duty relay > (like headlights use) with an 8-amp continuous capacity to carry the high > wattage that the window defroster draws. > > And to those of you who sent tips about repairing damaged grid wires: > Thanks for the tips. I suspect that comes next! Does anybody know the > correct resistive load that the rear window defroster is supposed to > provide? That way I can test it before the snow comes. > > Thanks, > > Bert > > |__n__ > (_____)? > (È\_|_/È) > ³ ? ? ³ > Polizeikõfer '70 > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Mike > Sent: Saturday, October 17, 2009 5:52 PM > To: Air-Cooled Volkswagen Discussion List > Subject: Re: [vintagvw] Rear window defroster wiring > > I believe that relay was originally located under the rear seat. > ----- Original Message ----- > From: Bert Knupp > To: 'Air-Cooled Volkswagen Discussion List' > Sent: Saturday, October 17, 2009 6:00 PM > Subject: [vintagvw] Rear window defroster wiring > > > Volks, > > The previous owner of my '70- beetle disconnected the rear defroster, > leaving a black wire in black spaghetti tubing dangling under the car, and > no visible connection up front at the fuse box. The little toggle switch > is > under the dash, and it seems to be okay, though not connected to anything. > I'm guessing it's a grounding switch for a relay. > > Who knows the correct factory routing for this wiring circuit? My > schematic > shows a relay, though none is present up front in my car. I'll assume it > draws coil power from a #15/54 circuit somewhere. > > What's the correct original wiring and routing for the rear-window > defroster? I'm guessing I'll need to thread a new front-to-back wire (1.5 > mm?) parallel to the main harness. I need to figure out where my orphan > black wire comes from -- and goes to. Do I pull #30 power from my voltage > regulator's battery terminal? > > The printed wire grid on the glass passes cursory visual inspection -- no > obvious breaks -- but I haven't put a meter to it yet. Does anybody know > what the proper (disconnected) resistance for it ought to be? > > You can send me stuff off-list at [email protected], if you'd like. > > Bert Knupp > > |__n__ > (_____)? > (È\_|_/È) > ³ ? ? ³ > Polizeikõfer '70 > > > __________ Information from ESET Smart Security, version of virus > signature > database 4518 (20091017) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > > _______________________________________________ > vintagvw site list > [email protected] > http://lists.sjsu.edu/mailman/listinfo/vintagvw > _______________________________________________ > vintagvw site list > [email protected] > http://lists.sjsu.edu/mailman/listinfo/vintagvw > > __________ Information from ESET Smart Security, version of virus signature > database 4518 (20091017) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > > > __________ Information from ESET Smart Security, version of virus signature > database 4520 (20091018) __________ > > The message was checked by ESET Smart Security. > > http://www.eset.com > > > > _______________________________________________ > vintagvw site list > [email protected] > http://lists.sjsu.edu/mailman/listinfo/vintagvw > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.422 / Virus Database: 270.14.20/2444 - Release Date: 10/18/09 09:04:00 > > _______________________________________________ vintagvw site list [email protected] http://lists.sjsu.edu/mailman/listinfo/vintagvw __________ Information from ESET Smart Security, version of virus signature database 4530 (20091021) __________ The message was checked by ESET Smart Security. http://www.eset.com __________ Information from ESET Smart Security, version of virus signature database 4530 (20091021) __________ The message was checked by ESET Smart Security. http://www.eset.com _______________________________________________ vintagvw site list [email protected] http://lists.sjsu.edu/mailman/listinfo/vintagvw
