sieumai

Car died on the road.
Replaced the battery and alternator on the spot.

1.) The sunroof completely stopped working. Reset doesn't work. Motor does nothing and makes NO sounds. I was able to reset the windows fine.

2.) The locking and unlocking button in the car works fine but NOT while the car is ON. I can hear it lock so that works but the unlock does nothing. When the car is off, unlock works.

Confused. Has this happened to anyone?

sieumai

Found the issue. The ECU-IG fuse kept popping. I had just put in rear TEIN Basis Z coilovers the night before and may have overextended the speed sensor cable (some people call it the skid control/abs sensor). Drove it through the rain and water might have gotten in there and shorted either one of the cables.

That in turn popped the ECU-IG fuse which controls the:
ABS
Air Conditioning
Back Door Opener
Charging
Cruise Control
Door Lock Control
Interior Light
Power Window (w/ Jam Protection)
Radiator Fan and Condenser Fan
Shift Lock
Sliding Roof
Tire Pressure Warning System
Wireless Door Lock Control

I thought it was the alternator and battery and had those replaced but those were not the problem at all. The ECU-IG fuse controls the charging output of the alternator (Red wire that goes into the alternator which is also connected to the ECU-IG fuse that popped cause of the short in the rear speed sensor cable). Looked through a 2007 scion wiring diagram which helped trace the wiring. The ECU-IG is connected to a junction called J1 and J2 and there was a short somewhere within one of those junctions because I still had functions in other parts of the car.

I went ahead and removed my rear seats and panels and disconnected the speed sensor cables from the harness and replaced the 7.5 AMP ECU-IG fuse. Everything started working! The fuse remained intact.

Now I have to figure out which speed sensor cable is shorted...
Going to connect one side and then the other to see which side blows the fuse so I can order the right cable..

bbsciontc

Wow, thanks for posting up the solution and explaining how you did it! So many people pop in here with questions and then disappear. Sounds like you know what you're doing with diagnosing electrical problems. I suspected something with the ignition wiring when you mentioned the door locks not working with the car on , but didn't know where to go from there. Was thinking maybe the key cylinder, but that was pure speculation so I didn't post up. Nice job figuring it out!

sieumai

Haha my first post seemed too broad and looked like there could have been a million things that could be causing the problem.

I should've checked the fuses first. Always check the fuses first!
Now I have a new Duralast alternator from autozone I cant return because its been installed and used.

I didn't know a fuse is in charge of actually telling an alternator to output.
What other mysteries does this car hold...?

bbsciontc

Yea, that is really odd. I guess it powers the voltage regulator, but I assumed those were internal to the alternator itself.

Luckily electrical wise, these cars are pretty solid. Only think I recommend keeping an eye on is for oil consumption. 2007 and up have a piston design (oil return holes) that are more prone to clogging up, leading to burning oil. I do believe that people who have always been running synthetic have fared much better though.