Rear Defroster Fuse Location
- Thread starter huntin5L
- Start date
You didn't answer about the mirrors but in theory the idle should increase even if the relay is bad because the defogger idle up input to the ECU is on the control side of the circuit and not the power side. It implies the internal circuit in the defogger switch is bad or you have open wiring somewhere just after it.
The defogger is more than a simple switch. It's also an electronic timer. Check the relay or check the mirrors for heating (same thing) anyway. If they don't work jump the defogger switch and see if the relay operates. Or jump the relay and see if everything works but the symptoms point to a bad defogger switch or a wiring problem after it on the control side of the circuit. If you look at the schematic you'll see what I'm talking about.
The defogger is more than a simple switch. It's also an electronic timer. Check the relay or check the mirrors for heating (same thing) anyway. If they don't work jump the defogger switch and see if the relay operates. Or jump the relay and see if everything works but the symptoms point to a bad defogger switch or a wiring problem after it on the control side of the circuit. If you look at the schematic you'll see what I'm talking about.
there is also a box located in the hatch for the rear defroster too, and it could be that a 20+ yo car the heater lines have been damaged, question is has the defroster ever worked before this?, is the car new to you?
The car is probably a little over 1.5 years old to me, it never worked, the mirrors never heat up either, and i know this because sometimes i will have snow on them when i forget to brush them off. Yeah the idle never seems to increase when i turn that switch on, so you think it is the switch?
LOL! He presumably means the choke coil. Its a low pass filter to knock out RF signals picked up by the defroster grid on the back window. The opposite of an amplifier really! See here for details....
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=084
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?Section=Main&Page=084
jetjock said:
3p141592654 said:
Yeah I know but I wasn't going to call him on it. Obviously a passive LC network just from looking at the schematic.
To the OP: As I said since the idle doesn't increase it appears the defogger switch isn't supplying the ground required to energize the relay coil or tell the ECU to idle up. Pull the little switch panel off and check it. Beyond that I'm giving up because the circuit is so simple anyone with a 12 volt test light should be able to fix it. Try harder.