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Discussion Starter #1 (Edited)
Bought the car end of summer and the one contact was hanging off on the rear window. I bought a repair kit and fixed it and everything except 1 line worked.

Today, went to defrost and nadda. Light on the button comes on that's all.

Checked the manual and seems that on the passenger side there is a relay, a breaker, and for whatever reason, the fuse is located under the hood (lower) as part of a 'maxi fuse'?

The fuse says rear defogger/audio system and my radio/cd works fine, so assuming the fuse is fine(?).

I have no idea how to test relays/breakers, I do have a multimeter though. Any advice what/where to start?
 

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Testing them can be a pain in the ass, easier to test for power on either side. If power goes into a breaker, but doesn't come out, bad breaker. Relay requires a trigger, so it's not as simple. Luckily these cars use the same relay part number for multiple things, so you can swap one from a circuit you know to be good. Wiring diagram should show you where to start. I would check for power at the grid contacts first, check between both contacts, and to an external ground. If no power there, move down the line towards the source till you find power, then you've found the problem.
 

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Testing relays

Most relays are real easy to test. They simply have a coil that pull in when voltage is applied allowing the contacts to close and let the higher voltage go through. Most will work like this. They will have 4 or 5 connectors on the back. Usually labeled 85,86,87,87a, and 30. The 85 is almost always the ground for the coil and the 86 is the power. Lets just say it's for your lights. So you turn on the light switch which applies 12v's at about 10 amps to the 86 pin. It charges the coil inside the relay pulling in the connection between the 87 and 30 pins. The 87 pin will be a heavier wire to supply a higher amperage to the lights, lets just say 50amps. When the 86 gets power and using the 85 ground to pull in the coil and completing the connection between the 87 and 30 pin the 50amps goes to the lights. So make sure your ground on the 85 is good. Check for 12v's at the 86 when the switch is one, and check continuity accross the 87 to 30 pins. You can pull the relay and put it on the bench and just put positive to 86 and ground to 85 and check continuity accross the 87 and 30 pins. The 87a is usually for stuff like accessories, radio etc. The relay rest in the closed position on the 87a and to feed those accessories. When you crank your car, it will pull away from that position to feed all power straight to the 87-30 pins. I may have over confused that, and of course not are exactly the same. That is a general setup for lots of bosch's and others. If you need me to be a little more straight forward with how to test it, let me or others here know and we will help.

Jeff
 

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Discussion Starter #4
I looked online before posting for relay testing and seemed a pain in the arse, since most videos showed them pulling the relay out and using a spare 12v battery to test with... which I don't have.

I'll test contacts then try relay swapping. If I get power to the contacts, then I guess the repair I did must've broke. It's still attached to the glass (used that special conductive glass glue) but with the snow/cold maybe it cracked and I can't see it.
 

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Battery

You don't need an extra battery. If you have a couple of jumpers that will work fine. Just pull the relay, connect one to ground on the car and the other side to the 85 pin. Then connect your meter accross the 87 and 30 pins and take the other jumper and connect one side to the 86, then the other side to the positive side of the battery and watch your meter. Put it on ohms. It should close in. If you need more help just ask. You will be better off learning this as it will help you with so much more in the future. If your unsure about reading your meter, here is the place to ask. No pressure, no condemnation, no nothing but helping a fellow car guy. We all have had it, and get it. So come on, lets go.

Jeff
 

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Discussion Starter #6
Well, tested a few things, power does get to the rear, noticed that the left plug was half off, sadly not the issue. The repair kit, although still affixed, no longer seems to be making any electrical connection.

Stuck a piece of metal from the plug to a piece of the strip and seems to work, also learned that tin foil heats up fast and burns your fingers. :D

So... just use some solder? the repair kit (Permatex 21351) did work until the snow came, I guess maybe expansion/retraction lost the connectivity? Too bad because attached fine and gave it an extra drop or two afterwards to make sure it stuck and had a good connection. :S
 
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