Rear Defrost help pls.. it's getting cold in MN LOL - Toyota Nation Forum : Toyota Car and Truck Forums

Toukiee3 · 10-30-2009, 10:37 PM

My defroster doesn't seem to be working. i tested the power with a light tester and also tested the strips on the back windshield. It has power, but when it gets cold out and I need to defrost, it doesn't seem to be defrosting. I have no idea what's going on. The only way I'm defrosting now is idling my car for like 15 minutes so the heater up front circulates the whole interior and defrosts the back.

Any help would be great! I need to get this fixed before it's winter and starts snowing.

TBayToyotaBoy · 11-01-2009, 09:29 AM

Hey Toukiee, I'm not far from you (in Thunder Bay) so I feel your pain. My Camry's rear defroster started losing efficiency about three years ago, and I still don't know why for sure. My best theory is that the aftermarket alternators have voltage regulators that can't keep up as well as the factory Denso units. The defroster draws amps like crazy...

On mine, I never really managed to "fix" it. All I noticed was that idling the car took forever to defrost (like, as in more than 20 minutes). If I just let the engine warm up a bit and then drive, the rear window is defrosted in about 3 minutes...the higher rpms help the alternator to keep up with demand, I guess.

Hope this helps.

--Tim

Toukiee3 · 11-01-2009, 06:47 PM

I see.

Well, I just swapped out my alternator a few weeks ago with a 5sfe one that's a Denso. My old one was a rebuilt one from Autozone. It was only about 2 months old, but my battery light kept coming on. I believe the 5sfe one has a bit more amps than the 3sfe. I don't want to take it to the shop either because they'll probably just test the voltage and say it's working fine.

I'm thinking about getting a replacement kit for the lines, but it might not even work either lol.

TBayToyotaBoy · 11-02-2009, 08:27 AM

Eek, it might be either the fuse (less likely but check it anyways) or the wiring loom where it splices under the rear deck, by the strut tower. Sometimes the old wiring can snap after 20 years of slight movement and drastic temperature variations...grab a flashlight and inspect the wiring before you buy another defroster kit.

--Tim