no power to head unit after alarm

I am running a clarion CZ200 HU in a 2000 Acura Integra. I hooked it up with a vehicle specific harness that I spliced to the clarion harness. Unit functioned perfectly until I installed a Viper 5701 alarm. Now ACC power to stereo and cig lighter will not function. In cabin and underhood fuses are intact. Switched power on stereo harness probes 233mv as does each terminal of both the radio and lighter fuses. Constant power to HU probes 12.4v. Alarm functions perfectly. Any ideas?

How did you test the fuse? If you just visually checked it there is a chance it is blown but still looks good. Chances are very good there is a fuse blown somewhere, you just have to find it!Kevin Pierson

could you just bypass the vehicle ACC wire and run a new one? might save a headache?

Find the fuse that is blown.  It will be labeled as radio or lighter.

neither the lighter or radio fuses are blown. I tested the fuses visually and by probing the top contact points. I also swapped the fuses with fresh ones to make sure they weren't partially blown. Yes I could bypass the ACC to another source but that doesn't fix the problem.

I noticed you said each terminal of the fuses read 233mv! Which to me says it isn't the fuse, but something tells me it's still a fuse problem!

Also technically speaking, bypassing the acc with a fresh wire will "fix" the problem, It just doesn't resolve the current issue!

commit your way to jehovah and he will act in your behalf. psalms 37:5

t&t tech wrote: I noticed you said each terminal of the fuses read 233mv! Which to me says it isn't the fuse, but something tells me it's still a fuse problem! Also technically speaking, bypassing the acc with a fresh wire will "fix" the problem, It just doesn't resolve the current issue!

so what would be my next step be? I was assuming that there must be some sort of major resistance on those two lines, but I don't know enough about electronics to know how to check that.

Did you unplug the ignition harness during the installation of the alarm?  I wouldn't be looking for added resistance I would be looking for an open in the wiring.  Either you unplugged something and didn't plug it back in right (ie backed the pins out of the harness) or you have blown a fuse.  If you have checked the correct fuses with an ohm meter and they are 100% verified to be good I would start checking any harness that you may have unplugged.

Also, if the radio and cigarette lighter have seperate fuses and neither of them work then that points to a wiring problem before those two circuts branch off from each other.  That is what got me thinking that a main ignition harness may have been unplugged to install the alarm and something didn't go back together correctly.

Kevin Pierson

KPierson wrote: Did you unplug the ignition harness during the installation of the alarm?  I wouldn't be looking for added resistance I would be looking for an open in the wiring.  Either you unplugged something and didn't plug it back in right (ie backed the pins out of the harness) or you have blown a fuse.  If you have checked the correct fuses with an ohm meter and they are 100% verified to be good I would start checking any harness that you may have unplugged. Also, if the radio and cigarette lighter have seperate fuses and neither of them work then that points to a wiring problem before those two circuts branch off from each other.  That is what got me thinking that a main ignition harness may have been unplugged to install the alarm and something didn't go back together correctly.

I unplugged the ignition harness to wire in the ignition and starter intercept from the alarm, but it was plugged back in and all of the ignition and starter functions work fine. There are only 4 pins on the plug and I have checked them multiple times. The radio and lighter have their own fuses, so it must be something with the wiring pre-fusebox. What exactly is an 'open'? You mean an open wire?

An open is an break in the circuit.  When a fuse blows, that is now an open.