Rear defrost doesn't work

bosshog

Member
Joined
Oct 14, 2009
Location
Wild Rose, WI
TDI
2002 Jetta GLS TDI
I drive a 2002 jetta and my rear window defrost does not seem to be working. The indicator light comes on but the window does not defrost. The fuse is ok and the connections on the window are good. I'm guessing its the switch or relay does anybody know where on the panel this relay is located?
 

bosshog

Member
Joined
Oct 14, 2009
Location
Wild Rose, WI
TDI
2002 Jetta GLS TDI
I thank this entire site for all the things I've learned I seem to have a little trouble searching sometimes but not bad. Well back to the car maybe I got some bad info because I don't see a relay for that defroster on the diagram is it controlled entirely by the timed switch in the dash?
 

Herm TDI

Vendor
Joined
Nov 21, 2001
Location
Richmond, Maine...The far side of Witsend
TDI
2002 Golf GLS Malone Stage 3, P+520 nozzles, 11MM Inj pump, Sachs VR6 clutch, Stelth Race Pipe, Immo Deleat, EGR Deleat
The rear defogger is powered by the load reduction relay through the defogger switch.

What I would recommend is pulling the switch and check continuity.
The switch is most often the weak link in this circut.
 

Herm TDI

Vendor
Joined
Nov 21, 2001
Location
Richmond, Maine...The far side of Witsend
TDI
2002 Golf GLS Malone Stage 3, P+520 nozzles, 11MM Inj pump, Sachs VR6 clutch, Stelth Race Pipe, Immo Deleat, EGR Deleat
rear defog switch

I am having a similar issue. The switch lights up, the fuse is fine. Would the switch light up if it was causing the problem as mentioned above?
Yes.
The "switch light" only indicates that there is power to the switch (fuse is good).
You need to take a meter and check for voltage at the window heat element.
With the switch on, then check for voltage at the window heat element.
No voltage at the window heat element = defective switch.
 
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Herm TDI

Vendor
Joined
Nov 21, 2001
Location
Richmond, Maine...The far side of Witsend
TDI
2002 Golf GLS Malone Stage 3, P+520 nozzles, 11MM Inj pump, Sachs VR6 clutch, Stelth Race Pipe, Immo Deleat, EGR Deleat
Switch P/N

Snip....Snip: Do you happen to know the part number for the switch?
The P/N: 1J0-959-621-D-01C {Switch for heated rear window}
This P/N is for the 1999.5 as indicated in your profile.
In the future if you require part # information please provide your full car info. Most perfered is the VIN as this will prevent mistakes and you buying incorrect part/s.
 
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15austin

Well-known member
Joined
Oct 10, 2012
Location
SW Missouri
TDI
2000 Jetta GLS TDI 5spd
Sorry to bring back an old thread, buy where or how do I check it the rear defrost at the window? I have a mulitmeter so where do I put the terminals?
 

Herm TDI

Vendor
Joined
Nov 21, 2001
Location
Richmond, Maine...The far side of Witsend
TDI
2002 Golf GLS Malone Stage 3, P+520 nozzles, 11MM Inj pump, Sachs VR6 clutch, Stelth Race Pipe, Immo Deleat, EGR Deleat
meter

Sorry to bring back an old thread, buy where or how do I check it the rear defrost at the window? I have a mulitmeter so where do I put the terminals?
Place the meter wires at both ends of the window heat element.
Set your meter to 12VDC
 

Was a fordie

Veteran Member
Joined
Mar 20, 2015
Location
Wausau, WI
TDI
2012 Jetta TDI
do u know if theres a part number for a new window defroster element.. looks like a small wire with a grommet. and some broken glass is attached to it yet with what looks like some type of window/mirror glue... I would like to get two that i could easily mount onto the back glass that is on the kit of the project im working on and still have functioning rear defrost.
 

Allen03

New member
Joined
Dec 29, 2016
Location
Iowa
TDI
2003 Jetta Tdi
03 jetta rear defrost not working

Have read down this thread and if I have 12 volts at window connections. Does that mean the heating element in the window is bad? It also has aftermarket tint on it doesn't appear to have been removed.Everything I have checked ahead of the window checks out good has continuity through the switch as well switch is lighting up and know that only means the switch Is getting power but I'm kinda at a loss at this point any help appreciated sorry for bringing back such an old post
 

TDIFan1989

Veteran Member
Joined
Nov 28, 2013
Location
Toronto
TDI
2000 Mk4 Jetta TDI (Black)
Yes.
The "switch light" only indicates that there is power to the switch (fuse is good).
You need to take a meter and check for voltage at the window heat element.
With the switch on, then check for voltage at the window heat element.
No voltage at the window heat element = defective switch.

A warning story for anyone out there looking into this problem, power at the defroster switch (red illumination when the daytime running lights are turned on) doesn't always mean the fuse is 'good'

I had picked up some of these 'Glow when they Blow' fuses from Princess Auto. Didn't think too much to check them at the time. Had the defroster switch prematurely stop operation during a cold night run to the store. Red illumination was still present but the switch was not clicking in to engage. Thought the switch was dead internally somehow. I still had power at the fuse right?

After swapping out the switch with my mechanic, I still saw the same symptoms. At this point I suspected the fuse. Mk4 Jetta lists as Fuse 26. Fuse is one of those 'Blow and Glow' ones I had put in. Testing across the terminals indicated continuity but the fuse portion was clearly showing soot like it had blown.

Tested out other fuses I had around, same deal, the fuse portion would blow but the fuse was still letting trace power past. I reported them to Princess Auto. Word to the wise, check the fuse if you have a specialty type.
 
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