Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

- - - - -

Rear window defrost


  • Please log in to reply
25 replies to this topic

#1 Guest_Kickerz_*

Guest_Kickerz_*
  • Guests

Posted 11 January 2002 - 01:41 PM

My rear window defrost in my 99' SUS seems to get warm at best and takes awhile to get there. Any ideas to why it takes so long to get warm and why it doesn't get hot enough?

Thanx in advance

#2 Guest_OutbackKY_*

Guest_OutbackKY_*
  • Guests

Posted 11 January 2002 - 02:39 PM

Can you explain in a little more detail? Can it clear a simple fog? How about snow? Ice?

Bryan

#3 Guest_Kickerz_*

Guest_Kickerz_*
  • Guests

Posted 11 January 2002 - 02:44 PM

It does clear fog or condensation nicely but IMHO not fast enough in comparision of past vehicles that I've had with RWD. When it comes to colder temps and ice formed on the back window it will take an honest 20minutes before a thin layer of ice is melted to where the driver can see clearly through the rear view mirrow.

#4 Guest_OutbackKY_*

Guest_OutbackKY_*
  • Guests

Posted 11 January 2002 - 06:28 PM

Not trying to be a smartass (honest!), but have you ever considered using an ice scraper when there's ice on the windows? My guess is the defogger/defroster on the window was not designed to thaw out ice. 10 seconds of scraping ice goes much faster than 20 minutes of aggravation while looking into the rear-view mirror.

Bryan

#5 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 11 January 2002 - 10:09 PM

FWIW the rear window defrost on my 95 isn't particuarly impressive. It won't clear much if there's buildup of anything (you know, like a coating of mist) on the outside. Pretty much need the wipers and need to heat up the inside of the car with the blower to get that stuff off.

I think the 95-99 setups are pretty much identical on this.

#6 Guest_Torch n Hammer auto repair_*

Guest_Torch n Hammer auto repair_*
  • Guests

Posted 11 January 2002 - 11:18 PM

Did you check the fuse. Perhaps it isn't seated well or the amperage is wrong. It does sound like 20 min is too long. My OB wagon clears ice and snow pretty quick. If I keep the RWD on snow or ice will not accumulate while driving it will melt (15 to 20 degrees, moderate snowfall). On a good thick frost the RWD burns through the frost so the "wires" are clear in about 3 to 4 minutes.

Bryan,
Why scrape? That whole clear vision thing is way overrated! :-)
Greg

#7 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 12 January 2002 - 10:38 AM

Torch,

What year is your OB?

#8 Guest_Torch n Hammer auto repair_*

Guest_Torch n Hammer auto repair_*
  • Guests

Posted 12 January 2002 - 12:38 PM

Russ,
I should have been more clear. My wife HAS a 96 OB and I get stuck with the 91 Legacy Wagon. Both 2.2, 5 speed AWD. So understand when I say "I have an OB" that means I wash it, wax it, change the oil in it, clean the interior, put tires on it and drive it when she lets me!
Greg

BTW the 91 Legacy RWD cleans off pretty quick too.

#9 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 12 January 2002 - 03:56 PM

Heh...

Guess I'll go check the fuses on my '95. Any idea which specific one it is? :)

#10 Guest_Torch n Hammer auto repair_*

Guest_Torch n Hammer auto repair_*
  • Guests

Posted 12 January 2002 - 04:32 PM

Russ,
It is fuse #7 under the dash on the drivers side. 20 amp.
Greg

#11 Guest_mrtoyou7747_*

Guest_mrtoyou7747_*
  • Guests

Posted 13 January 2002 - 01:52 PM

Cleanliness of the rear window does have an effect on the efficiency of the RWD. Thing's don't stick well to clean surfaces.

The heat produced by the RWD is proportional to the square of the voltage applied to the heater grid. So small decreases in the voltage at the RWD terminals will have a significant effect on the "heating" of the window. In the winter when you first start the car (recharge battery) run with the lights and heater blower "on" you will have a lower voltage at the RWD as the battery is being recharged. Todays cars with all the electronics and accessories running will draw a lot of current

#12 Guest_canajun2eh_*

Guest_canajun2eh_*
  • Guests

Posted 13 January 2002 - 09:05 PM

I had that "slow defrost" problem with my 92 Legacy wagon.

It turned out that I had *3* bad electrical connections in the defroster circuit. One was inside the tailgate (bad ground), and two were in the wiring run from the rear to the front. There was a fair bit of corrosion in two of the connectors inside the passenger compartment (right side).

When I fixed these bad connections by making permanent soldered connections instead of the plugs, the functioning of that defroster improved dramatically. The defroster will now melt 1/4" ice within 5 minutes to the point where the rear wiper will clear it off easily.

#13 Guest_Sam_*

Guest_Sam_*
  • Guests

Posted 13 January 2002 - 11:29 PM

I agree that you ought to clean the connections on the rear window. Be carefull as the metal tabs can brake off easily.

#14 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 14 January 2002 - 12:14 AM

Hmm guess I'm going to be doing some defroster 'tune up.' :)

#15 Guest_NV Zeno_*

Guest_NV Zeno_*
  • Guests

Posted 14 January 2002 - 12:22 AM

Hmmm...me too.:)

#16 Guest_Bagheera85_*

Guest_Bagheera85_*
  • Guests

Posted 14 January 2002 - 08:19 AM

There's kits you can buy that can find the lines that have a break in them.. sometimes, if you look closely, you can actually see them yerself.

#17 Guest_Kickerz_*

Guest_Kickerz_*
  • Guests

Posted 14 January 2002 - 08:45 AM

Thanx for all the replies! I guess I was looking for an easy fix but unfortunately I think I'll have to go through and see what type of amperage I have at the fuse box and compare that to the connections in the back of the car. If the amperage drop is significant I probably have the same problem as Gerry. I'll keep the board posted as repairs are under way.

Oh, and yes scraping does help alot Bryan but if you have the RWD option why scrap just hit the button. Like Gerry's OB, the ice should melt off in no more than 5 minutes. Me just being lazy I guess.....

#18 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 05 February 2002 - 02:57 AM

I stuck this thread to the top because it's on its way to the archives, if you want to add stuff then do so now, going, going... :)

And oh, can anyone tell me where those contact plugs are on a 92 sedan? Haven't exactly ripped things apart at the rear window just yet, but in spite of having 5 volts at the centerpoint of each element 'line', there is very little heat being generated.

#19 Guest_mrtoyou7747_*

Guest_mrtoyou7747_*
  • Guests

Posted 05 February 2002 - 04:55 PM

5 volts is low to me means you have some significant series resistance in the contacts or the wiring.

Remember P=Vsquared/R so 5 volts wil give you 25/36 of the power (=heat)

#20 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 05 February 2002 - 05:51 PM

Ok, so where are the contacts? :)

#21 Guest_keenr_*

Guest_keenr_*
  • Guests

Posted 06 February 2002 - 12:54 AM

"My wife HAS a 96 OB..." "I wash it, wax it, change the oil in it, clean the interior, put tires on it and drive it when she lets me!" :lol: :lol: :lol: I know THAT story! At my house it went, "I need a mini van." Got one. Now I hear, "It's too big and too hard to park. I'll just take YOUR car." :lol: :lol:

#22 Guest_mrtoyou7747_*

Guest_mrtoyou7747_*
  • Guests

Posted 06 February 2002 - 09:22 AM

The contacts are the metal "tabs" which are bonded to the metallization on the window (where the traces start) to which the wires are attached.

Make sure that they are tight and not corroded from water etc.

Be carefull they are only "glued" on. If you break them off you can replair them with some special goup you can buy at the auto parts place

#23 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 06 February 2002 - 05:39 PM

Hm. Well, since I seem to be talking something different I guess I'll have to just pry open the panel behind the back seat.

On the 92 Legacy sedan these contacts aren't visible. Yeah, they're back there, somewhere, but since they have to be there and they can't be seen they must be under the panel the high stop light and speakers are sitting in/on. Will figure out how to pry it up and see, and then I'll tell you guys and we can archive this thread for posterity :)

#24 Guest_SmashPDX_*

Guest_SmashPDX_*
  • Guests

Posted 11 February 2002 - 12:43 AM

Ok, I went after the defroster contacts. Didn't get to 'em but I think I know where they are. On our 92 sedan the wires disappear behind some internal body panels and the contacts are probably there. Trouble is, those body panels are wedged in place by the back seat, which doesn't fold down. I'm sure there's a proper way to get those panels off but I don't know what it is, and from what I gather from the Mrs. the defroster works great so long as you're moving (or the engine is running, I suppose).

So I'm done a-chasin.' Thread is heading to the archives. Going, going...

#25 Guest_Legacy777_*

Guest_Legacy777_*
  • Guests

Posted 11 February 2002 - 08:45 AM

Getting the back seat off is pretty easy if you wanted to get it off to do some more looking.

There are two bolts that hold the bottom cushion on. Then you have to lift the front part of the bottom cushion up, so the back side drops down and unhooks from the top portion. Slide it out, take out the three bolts that hold the top cushion in, and then lift the top cushion upwards and unhook it from the car.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users