elchinoloco

I just recently installed an aftermarket head unit, so I know I musta done something. Ive searched and read similar threads, but they all pertain to either an '07 tC or an LED swap problem..

-I have an 05' tC
-When headlights are off, HVAC is ON... wtf? But when headlights are on, HVAC goes off.. would the fuse still be the problem?

If it is the fuse, is it the fuse box on the drivers side under the dash? What is it labeled?

After installing a buncha electrical mods, this is the first big problem Ive run in to.

Any help is appreciated.

imagin

Check your dimmer switch

elchinoloco

Yep checked that, no luck.. =/

Gonna call the dealer tomorrow, if anyone has experience with this problem, how long would it take for them to look at it and determine the problem? If it isnt too long I could go on my lunch.

amdforever

This is what a blown mini blade fuse would look like...which is what the tC uses http://www.societyofrobots.com/image...fuse_blown.jpg

However, if it lights with the headlights on...it strikes me as not likely being a fuse...possibly bad wiring done with the HU? If you haven't found the interior fuses yet you have to look up under the driver side of the dash, down where the brakes and stuff are. Its a black strip of plastic on mine, has a print out of where the fuses are and stuff. I think the one your needing to check is 17 but I'd check all of htem to be sure.

elchinoloco

Yeah that got me thinking it might not be a fuse, since it does turn on.

What stumps me is that they are ON to begin with, when I put the key in the On position, they turn on, but when I put my headlights on, they turn OFF, which is the exact opposite of what its supposed to do.. hmm. Could it be coincidental that the HVAC is bad, or is it the wiring,

Ill see if I can have it checked out tomorrow (head unit wiring) by the installers at my work to see if I did something wrong.

Also, when I pull out the fuse, the key shouldnt be in right, or would I have to disconnect the battery?

engifineer

Did you tie into that harness for anything you installed?

Amoxaphobic

You mean that all lights on the HVAC are on? Not just the clock? What about the gauges? Do they light up when you turn the headlights on?

If everything else is working correctly, but some how the HVAC is not, then I would have to go with engifineers question - did you tie into the HVAC harness when you installed the HU?

My first guess would be the illumination wire (usually an orange wire from the HU). You might have that messed up.

equinox2355

I say try putting in the stock HU or at least plugging it in to see if that fixes it.

engifineer

Yep, if you in some way tied a wire into the illumination circuit from the car that should not be, it may be messing with you a bit. Take the stereo out, or unplug it, and see if the problem is still there. If so, try reversing that part of the wiring you did and see if that makes the issue dissapear.

elchinoloco

Well so far;

Headlights off:
-LCD display (clock) light is on
-Small square lights on the buttons turn on
-The back light on the button themselves that indicate what they are (A/C, OFF, MODE, OUTSIDE TEMP, etc etc) are off
-Gauges are off (of course)

Headlights on:
-LCD Display (clock) turns OFF
-Small square button dims down, but still on
-Button names still arent illuminated
-Gauges turn on normally

About the dimmer wire aka orange wire, at first I had that connected together, but I asked some installers at my work and they said that shouldnt be connected so I just chopped that off. No luck.

As far as tapping into the HVAC harness, as far as I know I have never tapped into any of those wires. This problem didnt occur till I installed my headunit. There might have been a POP sound, so it couldve been the fuse, what fuse is it for the HVAC?

Also, I called the dealer and Im still under warranty (3 years 30,000 miles), but the representative said that they would do a diagnosis, find out what is causing the problem, then call the warranty company and see if the problem itself was covered, and if it is, the diagnostics would be free, but if it isnt covered, it would be like $129 for the service... damn. So Im just going through every angle possible to find out what the frick I did wrong. Thanks for the help guys, appreciate it.

PS going to disconnect headunit completely right now.

kileil

Yeah, double check your dimmer wire is capped off and not connected to anything before you take it in.

If you haven't bought a wiring harness, do that to make sure your connections are correct.

elchinoloco

Yeah thats what I bought a wiring harness specifically for Toyota.

Amoxaphobic

It sounds to me like you are applying voltage when it's not needed, (when the lights are off), and maybe applying too much when it is (lights are on). Make sure that the wire you connected it to (not the one from the HU) is connected properly and not touching anything else. Cap off the HU wire as well.

You should really try to undo your install and see if that corrects the problem. If it does, then try to do your install again slowly and make sure you don't tap into the HVAC harness.

sciontc_mich

dealer calling a warranty company? um.. that company is TOYOTA! duh! (insult applied in dealer's direction for telling you something so dumb!) you're covered 3yrs/36k miles from Toyota themselves!!

and if you didn't install the HU, then I'd say someone did tap something and isn't telling you. Obviously a drain on the power somewhere.

engifineer

I would look for sure at all the wires that change levels when you power up the HU. For example, the power antenna or amp remote wire. Make good and sure where they are connected. Also, if the dimmer control input on the HU (if equipped) is connected right now, disconnect it to see what happens. If you start the car and turn on the lights... then power off the HU, does anyting change? (amp remote and power ant wire will be powered down when you power down the HU)

blazeplacid

some harness have 2 orange wires. i forget which is which but one is dimmer. you dont NEED it ,just take it off and switch em

Amoxaphobic

I don't know what the two orange wires would be... if there are two then I think one is a dimmer and the other is illumination. I think the only difference between the two is that the dimmer wire will allow you to adjust your lights with the rest of the lights like the gauges, but I could be way off with that one because I don't think I have seen two orange wires... not doubting you, blaze, I just haven't seen it.

Usually, there is a red, yellow and orange wire. Red will be ACC (Memory), Yellow is battery and Orange is illumination or dimmer. Then there is a black - ground and blue - remote. Most other wires will be in pairs... one as a solid color and the other with a line. These are usually your speakers.

Blaze is right that you don't need the orange wire. Just disconnect it. Again, I can't stress enough that nothing for and ordinary stereo should be plugged into the HVAC harness. You may run into situations where you might need to use something on the HVAC harness, but for those jobs, you will def know it.

Elchinoloco - If you can, take a pic of the wiring job making sure that you can clearly identify the wires. If you don't want to post pics of your work on an open forum, you can PM me with them. Don't be shy about your work, I won't criticize it. It can't be worse than when I was starting out. :D
Also, please keep us posted on the problem so we can continue to provide help.

LiquidFX

im having the same problem, going to go check it out some more today
I just had to get a NAV system....lol

LiquidFX

im still having this problem, anybody know how to fix it?

LiquidFX

im wondering if anybody has figured out whats up with this yet?