Headunit install- now i have NO dash lights, or taillights at nighttime. confused..
 

hey everyone, i keep searching to fix this but i cant find a thing. im a volkswagen guy that bought a scion as a daily drive 04, xb. so, since i had an old in dash monitor in my garage i decided to install it...after purchasing a harness kit everything seemed to be OK, cause it was day time. that night (which was last night) i got in my car, turned the headlights on and none of my interior lights come on (the heater control knobs and the guage cluster both are pitch black. assuming i missed plugging something in i just drove on route to my girlfriends thinking ill pull the dash tomorrow and plug in the plug i missed., 10 minutes later, i get pulled over. BOTH of my tailights arnt working, except both brakelights do work. :icon_frown: today, i pulled my dash and everything was fine. what could be the problem? i read on another page for a different model toyota that most headunits have thier own power sorce comming from a red wire, which my headunit does in fact have. they also said that a stock toyota uses a blue (idk if that correct in the xb case but ill continue) to power the headunit and when you have both installed you can blow a fuse or something of that nature (it had a strange name) anyway, my headlights work, and my dome light works but none of my dash lights work and my tailights dont turn on and stayon with the headlights at night unless i depress the pedal.

idk what it could be. i apperciate your time and anyone who can help me out is the man. thank you...mark

You popped a fuse. I believe it is one of the under hood ones label ACC. Pull out your owners manual and you will find the correct one.

i checked every single fuse in the car, they are all good. keep in mind, all my dashlights are off AND my taillights dont turn on when i put my headlights on, yet the headlights, blinkers and hazards all work, and the normal brake lights when i depress the pedal.

Ok so on to the next step if the fuses are good. Check your battery connection. Also check to see if maybe your tail light bulbs are shot? They are dual filament so this may be it but I don't think so?

Can your head unit be turned off? If so, try going for a drive but keeping the head unit powered off, and then try the lights and see if they work. I put a head unit in a car one time (although it wasn't a Toyota/Scion) and found out that aftermarket head units draw more power then the stock one, so when the head unit is powered on, there isn't enough power going to your controls for your lights (in my case my head unit would shut off when I turned the signal lights on). So it's just a suggestion that perhaps something like this could be the case for you. If it is, you'll need to wire in a Single Pole Double Throw relay that will distribute the power properly. You can find diagrams online somewhere of exactly how to wire it in, if this is what you need.

Sounds like a problem with the tail lights. As a safety feature when the tail lights go out the dash lights do too so that way the driver notices there's a problem. Double check your fuses, bulbs and grounds. Have a feeling it maybe a ground issue if fuses are good.

Theres another fuse box on the driver side foot well area. The little pocket just above your left shin, pull it out, more fuses in there. Might be one of those.

what kind of in-dash monitor is it? does it have a dimmer option on it? on a lot of the "big name" brands like pioneer, kenwood or alpine will have an orange and orange w/ white wire coming out of the harness that goes to you monitor. if you hooked these up try disconnecting them and tape them off. then power up the vehicle and run tests on all your lights. some wiring harnesses (for the car side) that you buy have those same colors but they are "backwards" and when you turn you headlights on and your radio dims, then you will open or ground out the factory wiring which may in turn, turn them off as if the headlights are turned off.
* if not that put the OG radio back in and see if the problem stays then work from there with the methods above.

Taillight fuse popping
 

Hey there,
I recently updated my headlight units, came with all bulbs. I had to put my old units bulbs back into new units. Fuse no longer popping, all lights now working. Hope this helps. Shawn