Defroster Problems

[DaN]

Hey Guys, need some help with the rear defroster on my 90 325i coupe.

The switch works, it has continuity through the correct terminals when depressed.

I measured the resistance to ground, through the defroster grid, it was about 23 ohms. Anyone ever check that on their car? Whats the resistance supposed to be?
If my calculations are correct, with a 12v source, it will only pull about .5A, and its supposed to draw about 25A, no?

I get ~12v at one side of the grid, and ground at the other.
There doesn't appear to be any break in the lines.
Why doesnt it work? lol

[DaN]

I just checked amperage draw, and it's only .43 amps. And upon closer inspection, only one of the lines is working. Damn.

There are no visible breaks, can I just repaint all the lines>? Lol

[kowalski]

I just checked amperage draw, and it's only .43 amps. And upon closer inspection, only one of the lines is working. Damn.

There are no visible breaks, can I just repaint all the lines>? Lol

i duno, im suffering the same problem, my defrost is super super slow... like for just foggy windows it will take 25 min + but somtimes it will take 5...?

[ak96ss]

I just checked amperage draw, and it's only .43 amps. And upon closer inspection, only one of the lines is working. Damn.

There are no visible breaks, can I just repaint all the lines>? Lol

You can certainly try, but in the long run it is easier to replace the rear window - like $200, less if you install it yourself.

I tried the self-repair, it was a PITA, time-consuming, looked like crap, and when it was done, still only half the grid worked. Then the rear window exploded one cold morning...

[DaN]

I guess I won't do anything. lol

[DaN]

Maybe I'll get one of these. http://www.frostfighter.com/ff_pdt_2600.htm

[Garageaholic]

that looks pretty cool. i saw it and scrolled down thinking the price would be a couple hundred,, but not bad for the price at all..... i hope it doesn't look too tacky though....

[ak96ss]

Maybe I'll get one of these. http://www.frostfighter.com/ff_pdt_2600.htm

IMHO (or not-so-humble), it is well worth it to just spend the bucks on a new rear window. The glass, with defroster, was about $207, but that was the inflated, your-insurance-company-called-us price - I'm sure you could save a few bucks by just sourcing one from your local Safetlite or something.

The new glass not only has a functioning defroster, it is CLEAN - you'd be surprised at the difference the minute, almost invisible scratches make.

It is well worth the money, and I regret having spent the 2+ hours I did trying to patch the grid.

Plus, to quote from the FrostFighter website FAQ:

Damage from window tint or removal
[SNIP] Unfortunately replacing an existing grid with the Clear View defroster can be problematic. It can be difficult or impossible to fully remove the existing defroster from your vehicle. We recommend using an single blade industrial razor blade to scrape the old defroster off the glass and even this technique can come up short on some vehicles. Often some evidence of the old defroster lines will remain even after scraping, the use of a cleaner like Comet or rubbing with a solvent. Normally the large side vertical side bars of the old defroster do not need to be removed.



Seems like an awful lot of work for this, whereas when you replace it, the back window is in and out in like 10 minutes.

Just my two cents.

[DaN]

Yea, I'll look into window replacement.

[DaN]

did some quotes online, about $226 installed. I don't have glass coverage.

[TwoJ's]

dude... get back glass from a wrecking yard. may not be brand new, but mine cost me $45. it was very easy to install too. do it.
________
buy vapir vaporizer

[ak96ss]

did some quotes online, about $226 installed. I don't have glass coverage.

I would call them in person - the glass will be cheaper and you definitely don't need someone to install it. They typically quote an exorbitant installation fee, plus they are including the price of a new rubber molding in that. Unless yours is dry-rotted or ripped, you more than likely won't need a new one. They wanted like $80 just for that.

The glass itself isn't too much, comparatively speaking.

Pull the lock strip out (carefully) of the rubber trim. Pop the window out from the inside (you don't want to have it come shooting out, though, so take it easy). Pull the rubber molding out, clean it and the window channel carefully. Put the rubber molding back in the channel on the car, and put the new glass on to it, starting at one corner. You'll need to lube the channel where the glass goes with foaming window cleaner or something like that. Then just carefully work your way around the glass, pushing the molding back in to place over the glass. The 'special tool' they used looked just like a plastic dinner knife - go to the dollar store and get a big package of them. Reinsert lock strip. Done.

I'm positive it will take you longer than it would them, but it is NOT hard.

As far as getting used back glass, if you are replacing the glass to get a functioning rear defroster, I'd say you're better off buying new - then you will know that it will work. Why go through the effort with the chances that your 'new' back glass is worse than the old? Not to knock putting used glass in - it's certainly cheaper, but it is used...

Here's what it looks like with no glass: :D

[DaN]

Oh, so it doesn't use adhesive on the back glass? It just slides into the rubber groove and the lockstrip covers it?

Sounds easy. I thought I would have to deal with cutting the adhesive and shit, I hate that stuff.

[asubimmer]

dood its sooooo easy to change the rear window...mine broke a few weeks ago and I just changed it this weekend w/ the help of a friend and it was to easy.

[ak96ss]

Oh, so it doesn't use adhesive on the back glass? It just slides into the rubber groove and the lockstrip covers it?

Sounds easy. I thought I would have to deal with cutting the adhesive and shit, I hate that stuff.

Nope, no adhesive - very easy. After watching the guy install it, I felt like kicking myself for actually paying someone to install it. Particularly since, as you can see from the picture, I had no back glass to take out. Half the job was already done.