| Author |
Message |
pyrOman
Fire Master
Joined: July 21, 2003
Posts: 12409
Location: Over 2002 posts deleted!
|
 Posted: Thu Nov 29, 2018 3:06 pm Post subject: Rear Defroster Glass |
 |
|
How do you test it? 
_________________
Some people are so busy being clever they don't have time enough to be wise. |
|
| Back to top |
|
 |
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24764
Location: Olympia Wash Rinse & Repeat
|
| Posted: Thu Nov 29, 2018 3:14 pm Post subject: Re: Rear Defroster Glass |
|
|
Connect electrical leads to a DC power source and spray the glass with a fine mist of water. If the lines dry of water first, then it works.
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
c21darrel
Samba Member
Joined: January 22, 2009
Posts: 8211
Location: San Dimas
|
|
| Back to top |
|
|
mandraks
Samba Member
Joined: November 28, 2004
Posts: 7050
Location: Lawrenceville, Ga
|
| Posted: Thu Nov 29, 2018 5:56 pm Post subject: Re: Rear Defroster Glass |
|
|
they usually work unless the wire is interrupted somewhere. That can be "fixed" too.
_________________
regards
Uli
----------------------------------------
'53 3-Fold Oval, L35 Metallic Blue, looking for a narrow hatch panel |
|
| Back to top |
|
|
busdaddy
Samba Member
Joined: February 12, 2004
Posts: 51153
Location: Surrey B.C. Canada, but thinking of Ukraine
|
| Posted: Thu Nov 29, 2018 6:51 pm Post subject: Re: Rear Defroster Glass |
|
|
Really?, maybe in a desert climate, around here the conductive stuff has been corroded off from too many years of damp climate, they aren't like modern ones.
A Hanes or Chiltons manual for almost any vehicle from the 70's or 80's will have a section describing how to test and troubleshoot a defroster grid, sadly most VW heated windows from that era are so far gone it's not worth the time to attempt repairs.
Luckily a new one isn't much money at all: http://www.busdepot.com/j13431
_________________
Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
|
| Back to top |
|
|
Clara 
Samba Member
Joined: June 14, 2003
Posts: 12401
|
|
| Back to top |
|
|
mandraks
Samba Member
Joined: November 28, 2004
Posts: 7050
Location: Lawrenceville, Ga
|
| Posted: Thu Nov 29, 2018 7:21 pm Post subject: Re: Rear Defroster Glass |
|
|
| busdaddy wrote: |
Really?, maybe in a desert climate, around here the conductive stuff has been corroded off from too many years of damp climate, they aren't like modern ones.
...
Luckily a new one isn't much money at all: http://www.busdepot.com/j13431 |
for that price i would also get a new one. then again if i already had one that looks good i would give it a shot.
_________________
regards
Uli
----------------------------------------
'53 3-Fold Oval, L35 Metallic Blue, looking for a narrow hatch panel |
|
| Back to top |
|
|
BarryL
Samba Member
Joined: November 01, 2004
Posts: 14271
Location: Casa de Oro, California
|
| Posted: Thu Nov 29, 2018 7:30 pm Post subject: Re: Rear Defroster Glass |
|
|
| pyrOman wrote: |
| How do you test it? |
12 volts negative to one side positive to other side. |
|
| Back to top |
|
|
LAGrunthaner
Samba Member
Joined: March 18, 2007
Posts: 5509
Location: 1st Coast
|
| Posted: Fri Nov 30, 2018 3:51 am Post subject: Re: Rear Defroster Glass |
|
|
Wow only $100. for a new one is pretty cool.
| busdaddy wrote: |
Really?, maybe in a desert climate, around here the conductive stuff has been corroded off from too many years of damp climate, they aren't like modern ones.
A Hanes or Chiltons manual for almost any vehicle from the 70's or 80's will have a section describing how to test and troubleshoot a defroster grid, sadly most VW heated windows from that era are so far gone it's not worth the time to attempt repairs.
Luckily a new one isn't much money at all: http://www.busdepot.com/j13431 |
_________________
American Red Cross Safe And Well:
https://www.redcross.org/about-us/news-and-events/...bsite.html
Maui Roadsters 
www.mauiroadsters.com
http://www.oacdp.org
| Lind wrote: |
| Have you considered simply starting with a nicer bus? I don't know what your skills are, but the race is easier if you can see the finish line. If you are not a runner, don't start off doing a marathon. |
|
|
| Back to top |
|
|
flemcadiddlehopper
Samba Member
Joined: December 05, 2011
Posts: 2332
Location: Kelowna, BC. Canada.
|
| Posted: Fri Nov 30, 2018 7:31 am Post subject: Re: Rear Defroster Glass |
|
|
It can be tested with either an Ohmmeter or a simple low impedance test light. Each line can be tested separately by connecting power to one side and the test light to ground, then gently and carefully pushing the tip of the test light onto each line. The same process with the ohmmeter without the use of power, just testing for continuity. Which actually works better as the resistance of each line can be measured and possibly detect a fault before it fails.
The repair kits are pretty cheap and easy to use, just tape it off and paint it on.
Gordo.
_________________
Everybody Dies....Some Never Live.
Retrograde Garage. Vintage Aircooled, and others. |
|
| Back to top |
|
|
Bruce Amacker
Samba Member
Joined: December 26, 2007
Posts: 1786
Location: Cleveland, Ohio
|
| Posted: Fri Nov 30, 2018 7:55 am Post subject: Re: Rear Defroster Glass |
|
|
| flemcadiddlehopper wrote: |
| Each line can be tested separately by connecting power to one side and the test light to ground, then gently and carefully pushing the tip of the test light onto each line. The same process with the ohmmeter without the use of power, just testing for continuity. Which actually works better as the resistance of each line can be measured and possibly detect a fault before it fails. |
I don't agree, this goes against the basics of electrical theory. You'll be measuring the resistance of the entire grid, not one line (unless many/every line is broken).
The best way to test any electrical heating device is using amperage, but the "hook it up and spray water" procedure is quick, dirty, and works. I remember being taught in class to fog the glass by breathing heavy on it while connected. Same idea.
_________________
'66 Deluxe Bus
'65 Standard Bus
Build threads:
'66- http://www.leakoil.net/forum/viewtopic.php?f=23&t=2888&sid=54d8dedfb3822f99c7f2ea430cb4e856
'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263 |
|
| Back to top |
|
|
hitest
Samba Member
Joined: September 30, 2008
Posts: 10296
Location: Prime Meridian, ID
|
| Posted: Fri Nov 30, 2018 10:21 am Post subject: Re: Rear Defroster Glass |
|
|
Ohms can be read very sensitively using Gordo's method- because they will read simply a stark difference on the lines that are broken in the absence of power. Ohm comparisons are the simplest way of dealing with conductivity testing on multiple, similar circuits. The guys who save money at swap meets are the guys with an ohmmeter in their pocket. 
_________________
| EverettB wrote: |
I wonder what the nut looks like.
|
'62 L390 151, '62 L469 117, '63 L380 113, '64 L87 311, '65 L512 265, '65 L31 SO-42, '66 L360 251, '68 L30k 141, '71 L12 113, '74 ORG 181
FU#5 |
|
| Back to top |
|
|
OB Bus
Samba Member
Joined: February 09, 2003
Posts: 2541
Location: Ocean Beach in Beautiful BLUE California
|
| Posted: Fri Nov 30, 2018 3:14 pm Post subject: Re: Rear Defroster Glass |
|
|
I had a glass like that until recently. The heat never worked. I have only met about 2 people who have a functioning Bus rear defogger. (Unless they got the new glass..)
_________________
Larry in OB
Stop dead photo links! Post your photos to The Samba Gallery!
69 Westfalia and 2002 Eurovan Camper. |
|
| Back to top |
|
|
flemcadiddlehopper
Samba Member
Joined: December 05, 2011
Posts: 2332
Location: Kelowna, BC. Canada.
|
| Posted: Sat Dec 01, 2018 10:05 pm Post subject: Re: Rear Defroster Glass |
|
|
| Bruce Amacker wrote: |
| flemcadiddlehopper wrote: |
| Each line can be tested separately by connecting power to one side and the test light to ground, then gently and carefully pushing the tip of the test light onto each line. The same process with the ohmmeter without the use of power, just testing for continuity. Which actually works better as the resistance of each line can be measured and possibly detect a fault before it fails. |
I don't agree, this goes against the basics of electrical theory. You'll be measuring the resistance of the entire grid, not one line (unless many/every line is broken).
|
I think you misunderstood the process. Each line is being tested in this method.
The water method does show that a line does not work, but it does not show where the break in the line is.
With my method, if you have a bad line you simply work the neg. test lead towards the positive end until power (or continuity) is restored. You just found where you need to repair the grid.
There are many ways to test a grid. This is what to do if you want to fix it.
Gordo.
_________________
Everybody Dies....Some Never Live.
Retrograde Garage. Vintage Aircooled, and others. |
|
| Back to top |
|
|
|
