SVX Rear Defroster

[Chaos Fluffy]

Okay I've recently picked up a 1992 Subaru SVX LS-L in rough shape. We've (My father and I) already put a lot of work into it to get it back into a good condition, but it runs and has a clean title in my name. =D But we've run into and issue with the rear window. The wires and spade tab that connect to the opposing tab on the rear glass is broken off; the tab is in one piece, but we're not sure how best to reattach the tab. I'm thinking of using solder, but my dad ensures me that we won't be able to get the solder to work well enough to adhere both ends together.

 

Does anyone have an idea of how to repair this? I can provide pics later on if need be. And I'd really like to get this fixed before we put the headliner in.

[Caboobaroo]

Most auto part stores have a conductive adhesive that is made exactly for this issue. I've used it before in the past with good results.

[Fairtax4me]

I've repaired this a few times on my 95 and have learned a few things on how to deal with it.

 

It can be soldered back on, but its tricky to do properly.

Make sure the area where the tab sits is clean. Window cleaner is generally good enough to remove any dirt/oils from the area. Use a very fine sand paper (1500- 2000 grit) to lightly scuff the surface. Just enough to make it bright.

You need rosin core solder and a 60-100 watt soldering gun. A little 30 watt pencil iron isn't going to get the tab hot enough to hold.

 

The glass needs to be HOT. I'm talking sitting outside in direct sunlight on a 90° summer day hot. If the glass is cold you'll never get enough heat in that area to get solder to properly adhere to the metallic strip on the glass, and you run the risk of shattering the window by applying high heat to one small area on cold glass.

 

If its cold out, put the car inside a garage and point some heaters at the rear window to get it heated up. If you can't get it out of the cold, you should just wait until you have warmer weather to try this.

 

Hold the tab with a small pair of pliers to hold the tab, pre-tin both side of both pads on the tab. Tinning the top side of the tab increases the heat transfer capacity so the heat travels from the soldering iron tip into the pad faster. With the tab still hot from tinning quickly apply it to the strip on the glass and apply the soldering iron to one of the pads until it melts the solder and you see the solder flow out and the pad seats against the glass. Now do the same to the other pad. You'll have to swap back and forth to each pad several times to get the tab to sit flat on the glass, and it can be very tricky to hold the tab still the whole time. You need to tab to sit perfectly flat on the glass. It may take a few tries to get it right.

 

If you don't have any experience using a soldering iron, soldering on glass isn't where you want to start. Get some wire and some solder and practice for a while before you try it. Lots of resources online that can show you how to solder properly. Be sure you know how to tell what a cold solder joint looks like. A cold joint will not adhere properly, and the tab will just fall off again.

[naru]

A conductive epoxy like Permatex 21351 is probably a better solution.

[Chaos Fluffy]

Thanks guys. I'll look into the Permatex 21351. Both my dad and I are good solders, though he has some experience soldering to a window and I don't (I mostly deal with soldering wires and old aircraft cannon plugs/connectors. He deals with circuit boards, wires, connectors, etc; just not everyday.). Like I said before, he's not comfortable with attempting to solder, and neither am I. But the I'll be sure to post if we get it working and how.

[Fairtax4me]

I'm sure you could handle it, but like I said, the window has to be hot for it to work.

 

The conductive epoxy could work as long as the resistance isn't excessively high. The defogger grids on these cars don't work that well to begin with, and any extra resistance between the tab and the grid can cause a hot spot on the glass.

I tired one that seemed to function well electrically, but when the weather got very cold the tabs broke free from the grid again.

[Chaos Fluffy]

Sorry for the long time getting to the update. Had a lot of other things come up and forgot to post about it.

 

Anyways, IT WORKS! Pretty well, considering the model, too. My dad gave one shot at trying to solder it, but that didn't work. After that we got the Permatex kit for the job. It took us a couple of times to get it right, as when we got it on the first time all it took was a slight tap to make it come off. But that was before the epoxy set, and it made it a bit more of a pain to get it back up and set again.

 

Still, once we got it set finally, give it 4 hours to harden, and then we took what was left of the Permatex epoxy and mixed it with some J.B. Weld Minute-Weld. We put that mixture over the top of the tab to make it more secure. But it's working really good now. Roughly takes about 5-10 minutes to clear the back window, and I'm not seeing any signs of breaks in the grid lines on the window itself. So I'm really lucky there. lol Now we'll have to see how the extreme heat of Mobile, AL will take it's toll on the connect when it's not in use come August.

 

So with that, thank you guys for all the help!