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Rear window defroster problem?


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My defroster doesnt work on my 93 loyale the button lights up like normal on the dash when i push it, i checked for scratches on the inside of the rear window and everything looks fine. has anyone else had this problem and solved it? winter is coming and i really need this to work.

 

:-\

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first check the contacts that the rear defroster plugs into on the window to see if they're getting voltage... then you'll know if it's electrical or the window...

 

 

 

My defroster doesnt work on my 93 loyale the button lights up like normal on the dash when i push it, i checked for scratches on the inside of the rear window and everything looks fine. has anyone else had this problem and solved it? winter is coming and i really need this to work.

 

:-\

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Like spiffy said, check to make sure not only you have voltage to the rear window, but that all connections are solid to the glass.

 

The way to check the glass is this. Take a volt meter. Vehicle power off. You want to place one connection on the drivers side and one on the passenger side. You can place them anywhere along the vertical part of the electrical system ON the glass. When you do this, the voltage should drop to 0 (zero). If this does not happen, you have a break in the lines somewhere. A single cut from a razor that is nearly invisible to the eye can be enough to cause a break!

 

Give this a try and shout back your results along with the amount of voltage coming to the window.

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Like spiffy said, check to make sure not only you have voltage to the rear window, but that all connections are solid to the glass.

 

The way to check the glass is this. Take a volt meter. Vehicle power off. You want to place one connection on the drivers side and one on the passenger side. You can place them anywhere along the vertical part of the electrical system ON the glass. When you do this, the voltage should drop to 0 (zero). If this does not happen, you have a break in the lines somewhere. A single cut from a razor that is nearly invisible to the eye can be enough to cause a break!

 

Give this a try and shout back your results along with the amount of voltage coming to the window.

check with the car turned off?

or do you have someone turn the car on when you are at the back testing?:confused:

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You can actually do this test with the glass outside of the vehicle which is how we normally do it in the auto glass biz. No power needed.

 

All this test does is to check continuity, making sure that current can pass from one side to the other. If you take the volt meter and hold the 2 ends together, it should zero out. All you are doing is to put one end on each side of the glass to see if it does the same thing. If it zeros out, no breaks in the heating grid.

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I tested voltage drop at the grid, it zero's out which means no problems there, fuses are fine, what else is there?. I doubt that the wiring is bad, it is a 93 with 80k any other ideas?:confused:

 

i also checked drop in between each line across the window, they all check out ok.

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Not really, you'll find 5 or 6 under there and they all look the same (actually two diff part#s as I remember), wire color is the only diff, big black with white stripe are head lights (right/left) and I think the heater blower is green something, thats all I remember. A FSM wiring diagram would really help, all I have is a Chiltons and I've found it less than reliable on wire color.

 

Gary

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can you check for continuity between the wires at the glass and the relay or fuse box or wiring harness up front?

 

i'd like to know if any power is even getting to the rear window. can you trace the wires to the window and give them 12 volts, see what happens?

 

do you have a defroster light in the dash? if so, does it come on when you turn the rear defroster on?

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can you check for continuity between the wires at the glass and the relay or fuse box or wiring harness up front?

 

i'd like to know if any power is even getting to the rear window. can you trace the wires to the window and give them 12 volts, see what happens?

 

do you have a defroster light in the dash? if so, does it come on when you turn the rear defroster on?

I cant get out right now and test voltage on the wires but i can tell you that the relay, switch and dash light are fine.

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i'm not real familiar with the rear defrost, so pardon the lack of details. can you test continuity between the relay and the rear wiring?

 

or test for voltage at the rear when the defrost is turned on? (i know i already said that, just trying to consolidate).

 

is it possible for a relay to be compromised in some way that it still clicks but doesn't actually transfer power properly? have another relay you can swap in? if you verify voltage at the rear, then this suggestion is pointless obviously.

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Refer back to my prev post about tailgate wiring/connector. The way it is routed and supported, it is easy for damage to occur to the wiring there.

 

After the fuse, that would be the first place that *I* would check.

 

No FSM wiring diagram, sorry.

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I tested for voltage at the back today, no voltage which narrows it down to either a shorted wire or a bad output side of the relay. do i have to remove the headliner to trace the wires, or does anyone know where they actually run?
Where "at the back" did you test? At the window? Under trim panel in tailgate? (Sorry for sounding like a broken record. :) )

 

Not sure where the wiring runs through the body, but it (obviously) pops out at the top and enters the tailgate. Seriously doubt that you are looking for a short... that would blow a fuse. You are looking for an open circuit; broken wire or connector issue. Since the wire is part of a fair sized bundle, and you haven't said that your car suffered mid-body trauma recently, I would suspect that the bundled wire through the body is probably least likely to be the fault. Relay end or tailgate end where the wire comes unbundled sounds more likely.

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Thanks everyone for the help:grin: I finally fixed it! It was the right side connector

in the hatch that looked ok, but i looked a little closer and it was melted and caused the contacts to seperate. So i just cut it out of there and replaced it with a bell cap and it works.

 

Thanks Again!

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