I have a 93 4runner and the rear deforster doesn't seem to be working at all. The light on the switch lights up, the fuse is good, there is power at the fuse box, I checked the connectors on the window and there is continuity through the window grid, everything seems like it should be working. Here is my question, is there supposed to be a power and ground coming from the wires that attach to the defroster grid? If so how much power is supposed to be coming through them, on my tester it shows like .1 volts. If you know the correct voltage or if there is something else I should be troubleshooting please let me know. I searched for this and have already gone through most of what everyone else tried but maybe someone has it all figured out.

Thanks!

 

If its similar to mine, i got a first gen, you should get 12 volts with the window up, defrost on, at the terminal leading into the grid. also make sure the grid has a good ground. I've got a wiring diagram for a 1st gen, but i don't know how much different the 2nds are. Lemme know if you want it or have some more questions, i just went through the diagnostic on mine to get it working, so i might be able to help.

 

Ok, I think 1st and 2nd gen are probably about the same as far as the wiring goes, if you can email me the wiring diagram (Baxterfamily@mail.com) I would appreciate it. Like I said I am not getting 12 volts back at the window so it looks like it may be time to do a little more troubleshooting.
Thanks!

 

get your multimeter out and test the defrost bands on the window, if they show continuity then trace it back from there.

 

Did you check the connectors that attach the wires to the glass, I found one of mine was loose before.
And I've just emailed you a 2nd gen wiring diagram.

 

well i wont email the first gen wiring, if you're already getting the 2nd gen.. thanks eric. The relay if i remember correctly is next to the left rear tail light inside the cargo area. I believe you have to take the panelling off to get to it, but you might be able to access it from the compartment door. Check up to it for 12V and go from there. If you need help figuring out the relay, or want to know how to test it, give a shout.

 

You guys are awesome. With the information I have now I should easily be able to figure out the problem. Once I get home tonight I will do a little testing to see where the actual break down is, I will keep you all posted.

Thanks Again!

 

Sounds good, let us know.

 

Well. it seems after doing a bit of testing I found have a short somwhere in the black wire that brings the power to the rear deforster. I have tracked it down to an area between the defroster grid itself and a plug directly behind the storage compartment on the driver's side. From the storage compartment area it basically exits at the bottom of the 4runner, goes back up under the bumper, and into the tailgate area. I am pretty sure that the wire just got kinked a little to much and doesn't conduct anymore. I found continuity no problem in the white/black wire but no such like on the black one. This weekend I will just tap in and run a new wire to replace the problem one. Thank you all for your help. (especially the wiring diagrams!)

 

I got the same problem...would you mind sharin' the wiring schematics? And does anyone know if the wire in the passenger side rear cargo window a defroster or what?

 

Denk,
I will email the wiring diagram to you. The wire on the passenger side window is actually an antenna, the original radio had some kind of switching device and used the antenna that had better reception. When I hooked up my aftermarket stereo I just used the front power antenna and left the rear one unplugged. I though it was some kind of defroster at first too!

 

Colorado4runner...you have pm

 

Hey CO4Runner, I am in the middle of fixing all of my little problems with my '95 and it so happens that I have what looks to be the same defrost issue. Could I get you to forward me a copy of that wiring diagram so I could take a peek? I already broke open my tailgate and found that I had continuity down to the wire connections on the glass, but when I throw the switch, still nothing (although the light on the switch goes on). I had a blown fuse at one point but it is not blown now, so that does not seem to be the immediat issue. I am not getting any power (12V) to the glass with the switch on so I suspect a relay somewhere.
Oh, BTW, it looks as if we reside in the same city!
With my new 05 Tacoma, I have been chatting with the local CoTTORA organization. Have you checked out their association and done any 4-wheeling with them? Just currious.

 

OK, never mind on the need for the circuit (all though I am still interested). I started to trace the wiring myself and quickly found abrasions where the wires to the heating element run near the window lifting arm. Apparently Toyota thought it may be a problem and put a plastic shield there but it was slightly out-of-place and the wires were bent too far. It turns out that the wires were severed in two locations: at the bend and a little farther back at the place where they are mounted (plastic clip) to the tailgate structure.
Some new wire, a little soldering, and shrink tubing/electrical tape and it is working again. If anyone needs some more info, I have a few pictures to go along with.

 

hey gargoyle!

send thos pix! mine has the same malady and i would love to fix it before the snow flies. i had almost given up on finding out how to get it going again.

tia,

lee

 

Ditto for me, if possible.
I gave up on mine ages ago.

 

leebee, Scofco,
I posted the pix to my web site. No documentation at the moment but here are the links:
4RunnerTailgateA.jpg 4RunnerTailgateB.jpg 4RunnerDefrostA.jpg 4RunnerDefrostA.jpg
I have a few more but these seem to show the most. If you need a better description, let me know and I will do a quick writeup.
Looks like I need to make a page or two about my trucks now.

 

hey g!

thanks for the pix, ill be doing some major work on the old girl next week and that will be one i will try and make sure to get done. by all means, do the write-up, it will at least get others to check out their gate and see if anything is abraded and needing some tlc.

thanks again,

lee

 

I will see what I can do over the next few days. I already have a write-up on my fog light mod for the '05 Tacoma. I'll post a link to a new page some time in the next few days. Good luck on the repairs guys.

 

Hey All,

Just to thank everyone who has come before me and written concise "how to " stuff...mine was a victim of the black wire breaking right at the push-on connection at the glass...I merely crimped on another connector and voila...I didn't at first realize I had to affect the repair by sitting in the "way back" but what the hey...it WAS repairable - thank you Toyota

Wes