rear defroster not working
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
rear defroster not working
Turn the switch on, defroster idiot light comes on, no increased electric load.
Checked defrost circuit breaker, it works. 12 volts to one leg of the CB.
Disconnected both wires at the rear glass, no voltage to either wire with the key on and defroster switch on.
Checked connectors on glass with ohmmeter, .03 or something, so at least some lines are intact.
FSM references a defroster relay, where is this? Drivers side fuse panel didn't have it, not did the engine fuse panel.
Checked defrost circuit breaker, it works. 12 volts to one leg of the CB.
Disconnected both wires at the rear glass, no voltage to either wire with the key on and defroster switch on.
Checked connectors on glass with ohmmeter, .03 or something, so at least some lines are intact.
FSM references a defroster relay, where is this? Drivers side fuse panel didn't have it, not did the engine fuse panel.
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- Petros
- Highest Ranking Member
- Posts: 11941
- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: rear defroster not working
it is probably behind the kick panel above the passengers feet area. if you remove the glove box you can see a small panel with electrical components on the right side next to the heater blower motor. there are several relays there, one is for the starter, and several others for other systems, it is likely one of these.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
- dlb
- Highest Ranking Member
- Posts: 7447
- Joined: Mon Jul 06, 2009 9:03 pm
- My tercel:: '87 sr5, '83 dlx parts car
- Location: bc, canada
Re: rear defroster not working
peter is right, the rear defroster relay is behind the passenger side kick panel. check page 657 (BE-7) in the FSM for a pic.
- marlinh
- Highest Ranking Member
- Posts: 1586
- Joined: Sun Apr 08, 2012 9:15 am
- My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
- Location: Kootenays
Re: rear defroster not working
The wiring for everything that goes to the rear of the vehicle travels along the passenger side of the car. I have found broken wires in the flex tube at the top of the door before. Also, the connector for the rear hatch is under the side panel below the right rear tail light. You could check if you are getting power there. I have seen problems there too but it is usually due to rusted out rear quarter panels and moisture getting in. You shouldn't have that problem.
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
Re: rear defroster not working
Peter / David: thanks, my 1st gen only has the fuse panel, driver's kick panel and engine fuses! I was looking for exactly that sort of picture, but couldn't figure out where it was in the FSM. The rear defogger part of "body electrical" will also be very useful!
Marlene: ah ha! I was thinking I needed to take the entire panel apart to find the connector, thank you!
Marlene: ah ha! I was thinking I needed to take the entire panel apart to find the connector, thank you!
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- marlinh
- Highest Ranking Member
- Posts: 1586
- Joined: Sun Apr 08, 2012 9:15 am
- My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
- Location: Kootenays
Re: rear defroster not working
I have a factory electrical manual I photocopied from the dealer. It gives all the locations of connectors etc. It is more detailed than the wiring diagram in the FSM. If you have any specific questions maybe I can help. The manual is for an 86, but most of it is the same for other years.
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
Re: rear defroster not working
Okay, I'll let you know!
I just printed out the wiring diagrams from the FSM and taped them together to try and sort out a few wiring messes.
I just printed out the wiring diagrams from the FSM and taped them together to try and sort out a few wiring messes.
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- Petros
- Highest Ranking Member
- Posts: 11941
- Joined: Sun Jan 28, 2007 6:31 pm
- My tercel:: '84 Tercel4wd w/extensive mods
- Location: Arlington WA USA
Re: rear defroster not working
another important place to look is where the wire bundle passes from the body to the door itself. It is always flexing there and eventually the wire itself can fatigue and break inside the insulation so you can not see it by inspecting the wires. If you have power at the connector, but no power at the contact on the defroster, you two sewing type push pins and stab the wire and check for continuity. try it on either side of the bend where it passes from body to door first, this will help you isolate it if indeed it is an internal break in the wire.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
- marlinh
- Highest Ranking Member
- Posts: 1586
- Joined: Sun Apr 08, 2012 9:15 am
- My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
- Location: Kootenays
Re: rear defroster not working
Did you figure out your defrost problem yet?
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
Re: rear defroster not working
No, was preoccupied this weekend getting the rust out of Pokey's cooling system and getting good stuff back in. I was just pondering it last night, because it is bugging me!
It's on the list of things to do which includes but isn't limited to replacing the carb on the sedan and hooking up all the vacuum emissions systems (ugh), tilling up all the garden areas, planting a bunch of tulips, get the house heater working, find out why the fast idle on the wagon isn't working, install external AT cooler and remove towing stuff from the wagon, clean SR5 seats and install, install a bunch of trim pieces in the sedan, and of course try and fix the defroster!

Somewhat on topic though, before picture of rear window. The clear film came off, leaving the tint gunk which was dryrotted and only flaked off.

After a lot of scraping by myself and the wife, here's the result:

Not sure how to get it off the wires themselves, ideas?
It's on the list of things to do which includes but isn't limited to replacing the carb on the sedan and hooking up all the vacuum emissions systems (ugh), tilling up all the garden areas, planting a bunch of tulips, get the house heater working, find out why the fast idle on the wagon isn't working, install external AT cooler and remove towing stuff from the wagon, clean SR5 seats and install, install a bunch of trim pieces in the sedan, and of course try and fix the defroster!


Somewhat on topic though, before picture of rear window. The clear film came off, leaving the tint gunk which was dryrotted and only flaked off.

After a lot of scraping by myself and the wife, here's the result:

Not sure how to get it off the wires themselves, ideas?
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- marlinh
- Highest Ranking Member
- Posts: 1586
- Joined: Sun Apr 08, 2012 9:15 am
- My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
- Location: Kootenays
Re: rear defroster not working
None, those wires are delicate. Patience with a razor blade perhaps?
- dlb
- Highest Ranking Member
- Posts: 7447
- Joined: Mon Jul 06, 2009 9:03 pm
- My tercel:: '87 sr5, '83 dlx parts car
- Location: bc, canada
Re: rear defroster not working
jeez, i'm not sure what you can do there. when i removed tint, i used a hair dryer to heat the tint glue up a lot and peel it off slowly in large chunks. after that, i just had to rub all the remaining glue residue off using my fingers. it never flaked off.
i guess if i were you, i would just use my fingers to carefully work all the tint and glue off, if that's possible. good luck, paul.
i guess if i were you, i would just use my fingers to carefully work all the tint and glue off, if that's possible. good luck, paul.
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
Re: rear defroster not working
This stuff was weird, I heated it up good with the hair dryer, and the film came off leaving the tint crap behind. The top right of the before picture was apparently done before the tint crap had a chance to dry rot, it was clean!
I'm hoping if the defroster actually works, the heat from that might help me!
At this point I'm wondering if I should just source new rear glass, is it a pain to replace? Better to do the whole hatch?
I'm hoping if the defroster actually works, the heat from that might help me!
At this point I'm wondering if I should just source new rear glass, is it a pain to replace? Better to do the whole hatch?
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
- marlinh
- Highest Ranking Member
- Posts: 1586
- Joined: Sun Apr 08, 2012 9:15 am
- My tercel:: 'Everett' Blue 87 4WD Wagon (Rocky 86, recently retired)
- Location: Kootenays
Re: rear defroster not working
According to the manual, the glass pops out of the seal. I think Petros has experience with these. The chances of having a leak afterwards is always a possibility I guess. I guess it depends on what you can find. If you are coming up my way, I am getting two cars towed away soon. I have one rotten hatch with excellent glass.
- irowiki
- Highest Ranking Member
- Posts: 3469
- Joined: Tue Apr 02, 2013 10:02 am
- Location: Farmington, NM
Re: rear defroster not working
Unfortunately I'm not going up there anytime soon, most likely. If I was I'd totally snag your A/T and the rear glass!
I can imagine freight shipping from canada to the US is probably way too much.
I've been part searching and apparently there was a "Standard" defroster and a "heavy duty" defroster.

I've been part searching and apparently there was a "Standard" defroster and a "heavy duty" defroster.
Former Tercel Enthusiast (not a practical family car anymore but they still have a place in my heart)
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k
Site administrator, if something is broken, PM me!
87 Corolla FX16, 105k
94 Jamboree RV (Ford E-350), 90k
95 Camry Wagon, 197k
05 Avalon, 199k