[AnaRki]

wuddup guys, just messed up my car while installing my headunit. So far I am not receiving power to my head unit nor is my alarm working. At first i thought it was my radio fuse because it was blown, but after i replaced it, i was still was not getting any power to my hu. I believe i shorted the multiplex control unit under the dash/fuse box. I searched on these forums, but i cant seem to find where the control unit is located. Any help or advice would be much appreciated. Thanks


problem list
not receiving power to head unit
door locks won't work unless key is in the ignition
car alarm will not activate.

[christmaspie]

MCU is built into the interior fusebox. You might also want to check the "Back Up" fuse under the hood. Factory car alarm? Got a meter?

[AnaRki]

thanks for the info man, the backup fuse it fine. And yes i do have a meter. But as for the MCU, if i need to replace it do i have to go to the dealership? Thanks again for the help.

[electric130]

Originally Posted by AnaRki

But as for the MCU, if i need to replace it do i have to go to the dealership? Thanks again for the help.

i wouldn't want to do it. it would be a nightmare.

[christmaspie]

Originally Posted by AnaRki

the backup fuse it fine. And yes i do have a meter.

Good stuff, let's have you meter both sides of that BackUp fuse so we can figure out whether the problem is before or after the fuse.

Originally Posted by AnaRki

But as for the MCU, if i need to replace it do i have to go to the dealership?

As per electric130, sounds nasty. To be honest I would be surprised if that ended up being what you needed to do to fix the problem. Whether or not power is getting to the BackUp fuse will tell us a lot though.

[Ohiokie]

I just had a very similar problem with my '01 Civic. I also had trouble installing my head unit....shorted the +12V power to the radio to ground. I then checked quite a few fuses (finding none to be at fault). The radio didn't work, plus the power locks, dome light, and the don't-leave-your-headlights-on chime were also out of commission when the key was not in ACC position. My troubleshooting via the Haynes manual led me to believe the Multiplex Control Unit was at fault. I had poked around the interior fuse panel for a while before giving this forum a look, to see if anyone could point me to how to troubleshoot that MCU.

It turned out to be the "Back Up" fuse that was blown. My thanks and appreciation to this thread for saving me any more headaches trying to solve this problem.