Fried Switches

[Golddeenoh]

not sure how I did it but I just fried my second fog light switch. The only thing I can figure is something funny going on with the grounding. I do have a grounding kit but i removes the cable that shared that ground, the only thing i can figure out is something inside the car isn't as good as I thought it was or something going on with the dash. Any ideas?

[CTScott]

If you wired it using the OEM fog light relay, did you modify the switch before installing it to separate the lighting circuit from the switching of the lights?

[Golddeenoh]

the first switch had both resistors removed from the lights, the second switch only had the constant on light disabled. both switches when engaged would light p the fog light indicator on the instrument panel. before the last one went out the switch light came on but the dash didn't nor did the fog lights themselves. when it did the i turned it off and back on and the switch on indicator light in the switch flickered and went out.

[CTScott]

the first switch had both resistors removed from the lights, the second switch only had the constant on light disabled. both switches when engaged would light p the fog light indicator on the instrument panel. before the last one went out the switch light came on but the dash didn't nor did the fog lights themselves. when it did the i turned it off and back on and the switch on indicator light in the switch flickered and went out.

If you open the switch are the circuit board traces burned through?

[Golddeenoh]

doesn't look all burnt up at all. the switch looks normal, the best i can figure is that it is the button part of the switch that cooked or what ever it did that caused the flicker then failure

[CTScott]

doesn't look all burnt up at all. the switch looks normal, the best i can figure is that it is the button part of the switch that cooked or what ever it did that caused the flicker then failure

It sounds like you have it wired where the switch is switching the bulbs, rather than the relay coil (which in turn switches the bulbs). Those switches are only rated for 2 or 3 Amps.

[Golddeenoh]

that was kind of what I was thinking, plus my auto shop instructor said it sounded like the lights 30 amps was going to the switch instead of through the relay. Is there a wire that would have been close to the one in the instructions that I could have switched and not realized?

[Golddeenoh]

i tested the fog lights in class today and their is only a maximum of 150 mA. since i didn't think it right to ask for another switch I installed a toggle switch, which worked until i had the head lights on, then it broke again... not sure what the hell i did but as far as i can tell the fog lights are wired into the correct places but still I brake it.

anyone got a schematic of the OEM fog light circuit for the 09 Yaris 3 door? maybe i can trace and ponder a solution.

[CTScott]

i tested the fog lights in class today and their is only a maximum of 150 mA. since i didn't think it right to ask for another switch I installed a toggle switch, which worked until i had the head lights on, then it broke again... not sure what the hell i did but as far as i can tell the fog lights are wired into the correct places but still I brake it.

anyone got a schematic of the OEM fog light circuit for the 09 Yaris 3 door? maybe i can trace and ponder a solution.

The 09 fog light schematic is the same as the prior years, so you can grab it from the Yaris Files section of the Micro Image forum. The fog light switch only need to connect the two upper left wires together (the orange and yellow or white and yellow, depending on the package). When those wires are shorted together you are simply providing a path to ground for one side of the coil of the fog light relay (the other side of it has constant power).

The kit fog light switches failing is likely a failure of not the switch itself, but rather the circuit that bridges illumination and that switching to ground of the relay. On an OEM setup the illumination and switching occur via two separate circuits.

Was your toggle switch an illuminated one?

[Golddeenoh]

yes sir, it illuminated until it died.

[CTScott]

yes sir, it illuminated until it died.

Was it a three pin or four pin switch?

[Golddeenoh]

oh 3 pin, red toggle, auto zone special. i'm pretty sure i have mine wired in to be on with the tail/head lights(low beam) but if i flip the switch it would come on either way, head lights on or off.

[CTScott]

oh 3 pin, red toggle, auto zone special. i'm pretty sure i have mine wired in to be on with the tail/head lights(low beam) but if i flip the switch it would come on either way, head lights on or off.

That is at least part of the problem. You want to separate the illumination from the switching, so you really want to use a 4 pin switch where the twain do no meet.

[Golddeenoh]

is that why the kit's switch is split on one of the wires to put the light in the switch in parallel?

[CTScott]

is that why the kit's switch is split on one of the wires to put the light in the switch in parallel?

Yeah - That is why in my DIY for the fog light kits I have people cut out a resistor from the circuit board (to open the internal connection) and also split the four wires.

[Golddeenoh]

well my fog lights work...when they want to. yesterday the came on in the morning but wouldn't that evening, today they turned on every time. seems almost as if the BCU is seeing a different parameter than I was aware I had given it or that it had read.

[CTScott]

well my fog lights work...when they want to. yesterday the came on in the morning but wouldn't that evening, today they turned on every time. seems almost as if the BCU is seeing a different parameter than I was aware I had given it or that it had read.

The body ECU has no control over the fog lights.

[Golddeenoh]

i'm not sure which "brain" is doing the thinking for the fog light, just that it is fickle.

[CTScott]

i'm not sure which "brain" is doing the thinking for the fog light, just that it is fickle.

None. There is just the switch, fog light relay, and if you have DRLs, the DRL relay is in circuit as well.

[UberSilver]

well my fog lights work...when they want to. yesterday the came on in the morning but wouldn't that evening, today they turned on every time. seems almost as if the BCU is seeing a different parameter than I was aware I had given it or that it had read.

Does your Yaris have fog sensors?:biggrin::biggrin:

[Golddeenoh]

this appears to have been the problem it wasn't making a good connection in it and kept wiggling lose. I also moved my ground to better location the other one was questionable. now to see if it keeps working or starts being fickle again.