2 days ago, my dash lights went off and my headunit wouldn't turn on. If i had my lights off, the guages would light up, and headunit would turn on, but when you tried to play a cd, it said "error 2".
With the sidemarkers and headlights on, the headunit loses all power(wont even turn on) and guages wont light up. I checked all fuses and the only blown one i could find was the cig lighter. I replaced that and there was no change. When i hooked a voltmeter to the constant 12v on my headunit(First thought was bad connection) it would stay at 13.9 volts(normal) but when i would put a cd in, it would drop down to 3v and jump around like crazy. This has happened to a number of my friends eclipses, and were all stumped. Any help is greatly appreciated.

bump

come guys.. i know some of you have some answers

you have a backfeed situation. You lost a ground somewhere or you have a wire shorted to ground between the two circuits.

Terry

Thats what i figured.
The other day i replaced the cig. lighter fuse, disconnected my illumination wire from the remote wire on the hd cause i wasnt thinking and it worked but as soon as i hit a rough bump the guage lights went out and the hd turned off and now it refuses to work so im completely stumped. It's nice today so ill whip out the volt meter and probe till i faint and see if i can locate the promblem. If it helps any, I have no air conditioning or heat so i disconnected those connecters. I dont know but my friends guage lights wouldnt work and we located the promblem to be his rear windshield wiper cause he disconnected it so we ran a power wire to it and it works now.

Well...after spending this night searching for the promblem i have come up with nothing again. I had my lights on and molested every wire i could find and no change. One thing i did notice is when i have my lights off the guages light(as said before) but when i turn my head unit on, they get brighter...much brighter, but everything still turns off when i turn the lights on. Im fed up with this and have no idea what to do. Could someone tell me where the grounds are for the guages? thanks in advance.

Im thinking...could it be the dimmer? Im thinking mabey but what would that have to do with the headunit??

Originally posted by Slimyjr.
Im thinking...could it be the dimmer? Im thinking mabey but what would that have to do with the headunit??

Trouble shooting an electrical problem on a car that is no longer in OEM stock condition is a nightmare to do over the internet. Who knows how much has been spliced by alarm installers, stereo installers, previous owners and the like. It certainly sounds like some type of open gound condition but where, I can't easily tell you. You should find the wiring schematic for your vehicle year and print it out.

The OEM dimmer circuit is a pulse width modulated low-side switched design. Simply stated, it creates the effect of dimming the lights by very rapidly connecting and disconnecting the ground wire for every light on the instrument dimmer circuit. I'll have to check my schematics for the correct wire color but there is a simple way to test the dimmer by grounding the low side wire and seeing if all the lights come on at full brightness.

Does your dimmer knob still adjust brightness as usual?

EDIT: To test your dimmer circuit find any convenient bulb that is on the dimmer circuit and look for a black wire with a yellow stripe. I used a wire I found behind the pop out panel on the left of the gauge cluster (cruise/fog/mirror adjust). Behind that panel you will likely find an empty plug with a black/yellow stripe wire. Turn on your marker lights and then take a small test lead and a safety pin and ground out that wire to the car frame. Regardless of where the dimmer knob is set, your gauge lights should turn on at full brightness whenever that wire is grounded. If the lights work when the wire is grounded but not with the dimmer then the dimmer is either disconnected or non-functional.

Sorry azdave but i fixed it before i read your post.(pionts to you for your ounstanding knowleadge though) What i did was trace the wires to the ground which is ground number 5 for the 2g's. This ground is located just behind the guage cluster. I cleaned it up good with sandpaper and regrounded it. I also took the two dimmer switch black wires and spliced them and ran a new ground from the head unit to the chasis just to be safe and everything works great now.

I have seen something like that but what had happened is that the person wired his stereo ground wire into the illumination feed for the stereo. When ever his lights weren't on his stereo worked (weak backfed ground) and when he turned his lights on the illum feed turned positve and the stereo lost its ground and stopped working and would blow the fuse for the running lights. sorry can't be much more help than that without a testlight and dvom.