Tail lights stay on...strange electrical issue

[pgarland]

Ok, never before in my life have I ever encountered an electrical issue as strange as this.

The car shuts down randomly while I am driving...I mean completely shuts itself off (motor, radio, everything). It has been immediately cutting itself back on up until lately (like it will shut completely off, then start back up a fraction of a second later, and everything will be fine again). Today it decided to shut itself off completely and NOT cut back on...I had to pull to the side of the road, pop the hood, disconnect and then immediately reconnect the positive battery cable (as soon as I did this I heard a click, like a relay resetting itself or something...disconnecting and reconnecting the negative terminal did not produce a click, and did nothing to restore power to the car). Once I did that, the car started back up immediately, and ran fine for the rest of the way home (about 6 miles).

So I park the car in the driveway, and go off to help my neighbor fix his Firebird (had promised to help him all week...rear main seal...but that's all besides the point). Had to run back across the street to my house to get some tools, and when I walked by my car, I noticed my tail lights were on (just the tail lights...not the headlights or parking lights or even the interior lights for that matter). Thing is, the car was off, the head light switch was turned off, and the keys were nowhere near the car (they were in my house). First thing I did was open the driver's door, and step on the brakes really hard, then put my foot under the brake pedal and pull up on it to make sure the brake pedal was as far up as possible (thinking maybe for some reason the pedal was sticking...although only the tail lights were on, NOT the brake lights as far as I could tell). Anyways, I couldn't get the tail lights to turn off after turning the head light switch a bunch of times off and on and stepping on, releasing, and pulling up on the brake pedal. So I popped the hood, disconnected the positive battery terminal (and left it disconnected), closed the hood, and left it (by this time the battery was already pretty run down...didn't want to drain it any further).

Now I have a Sony 1200 watt amp pushing 2 Sony Xplod 12" subs (mind you, this has been installed in the car for well over 12 months and I have NEVER had a problem with my setup...installed it myself and I definitely know what I am doing)...but just to be sure it wasn't the system, I pulled the inline fuse out of my amp power cable when the car started having these power surges a month ago. The amp is NOT currently pulling ANY power from the battery at all (no fuse = no complete path for the 12v to run = no power to the amp...I'm rocking factory sounds for the time being)...and a quick check with the multimeter shows proper voltage at the hot side of the fuse when I connect it to ground...although strangely enough when I put the 30 amp fuse back in to the inline fuse connector and measure voltage at the positive terminal at the amp it drops to around 7 volts...does the same with different fuses (I have tried a bunch of brand new 25 and 30 amp fuses) and I even replaced the section of power wire running from the 12v+ amp input to the inline fuse as well (also checked and re-checked my ground, cleaned it up even more than it already was, and ran a new ground cable...and yes, my ground cable is as short as I could make it - less than a foot - and is properly grounded to the chassis)...I put this information here in case it may help, but I am at the point where I don't believe my sound system has anything to do with this craziness.

The power surges seem to happen completely randomly (sometimes with the radio and A/C on, sometimes with the radio and A/C off...sometimes when the car is warm, sometimes when the car is cold...etc). The only thing I can be sure of is that they seem to happen at the worst possible times (making a left turn across a four lane highway with a 18 wheeler coming the other direction...). The only thing I can compare them to is something like the "hitting a brick wall" feeling of fuel cut (which makes no sense as this is pretty much a bone stock, N/A 420A 2g Eclipse). Also, sometimes I'll get a CEL for my IAC, but it usually goes away within minutes (and besides the IAC is thoroughly clean and brand new). The battery is about a year old, and the positive and negative cables for the battery were installed at the same time the battery was.


Anybody ever come across anything like this before? Or have any ideas just what the hell could be causing this? I was planning to go ahead and do the Saturn alternator swap tomorrow (neighbor owes me for all the help today......he was gonna be sweating in the hot sun helping me do this tomorrow!), but I'm really hesitant to try to upgrade the alternator when I have some crazy unknown electrical goblin running rampant in my system.

Any and all advice is appreciated, and thanks in advance for at least taking the time to read all this. Save me electrical gurus!!!!!

 

[Locke]

The first and biggest thing that pops out at me is the fact that your tail lights are on without your other parking lights, with the ignition switch turned off. This wouldn't be the switch, or your front parking lights would be on as well. This is indicative of a short to hot.

Without me taking the time to look up where the tail light wires are ran, I would suggest you inspect the wiring from the tails forward.

In the mean time, I would suggest driving the vehicle as little as possible, and keeping the battery disconnected while not using it.

 

[pgarland]

Thanks for the quick reply Locke...

Today is the first day the tail light issue happened. All the other times I have experienced the electrical surge, the tail lights acted normal (turned off when I turned off the light switch). While I'm DEFINITELY going to follow your advice and keep the car parked until I get to the bottom of this, do you have any recommendations as to maybe where I should start to look to see about chasing down the possible short to hot? I will certainly do as you suggested and start from the rear of the car checking every wire I can (and I'll post back results tomorrow on that), but I am hesitant to believe that the short to hot is coming from the rear of the car what with all the other electrical craziness that has been happening prior to the tail lights deciding to go on strike.... Is it possible there could be a short in the ECU? Maybe the alternator shorting out somewhere? A relay stuck open in the engine fuse box? Could a bad positive battery cable do this (like maybe my amp power cable is somehow shorting to the positive battery cable)? Could a dying battery do anything like this? I'm no stranger to electronics, but this whole thing has me dazed and confused...

Like I said, I have never in all my years come across something so inexplicable as this...it's tough to figure out just where to really start!

Thanks a ton for the help...it is greatly appreciated. Any other help from anyone else is also extremely welcome, thanks in advance to all who offer up ideas.

 

[VelocitàPaola]

This is indicative of a short to hot.

Hot? Somebody's been doing too much 110VAC wiring recently...

Pat, out of curiosity, what voltage do you measure with the car running? In particular, what voltage do you measure at the battery, at the amp, and at the amp's fuse holder? It may or may not be related to the main problem, but 7V anywhere on the car is not normal.

As for the taillights, Locke pretty much hit the nail on the head. Check all the wiring from the taillights forward. How was the car when you got it? Was the wiring hacked to pieces, or was it basically stock?

Also, there's a relay that controls the taillights. It'd be pretty odd for it to fail closed, but it's still worth investigating. Try removing the relay, then check the taillights. If they're off, the problem is probably the relay or the column switch. Measure the voltage at each of the contacts in the relay socket, referenced to chassis ground.

 

[CODE4]

It is not strange if his brake lights are on without any other lights on - that means his brake light circuit is activating. Common problem on 2Gs - the plunger on the brake light switch under the dash contacts the metal plate on the brake pedal. Now for some weird as reason the exact spot where the plunger makes contact has a hole drilled in the metal plate, plugged by a plastic piece. When this plastic piece ages it will break apart opening the hole allowing the plunger to pass right through. Circuit believes the pedal is depressed regardless of actual pedal position.

Simple fix I have performed on a couple 2Gs - superglue a penny to the metal surface, covering existing hole.

Reference this thread: Team 2GNT Forum - Viewing topic #32874 - Just a heads up on our brakes....

 

[pgarland]

Hot? Somebody's been doing too much 110VAC wiring recently...

Pat, out of curiosity, what voltage do you measure with the car running?

From the battery, I get ~ 13V, and the battery seems to be charging just fine. I don't have a voltmeter gauge in the car (still in the "fix everything" stage of pre-modification for this car...I will NOT spend a dime on upgrades until this thing has proven itself to be a reliable DD!).

In particular, what voltage do you measure at the battery, at the amp, and at the amp's fuse holder? It may or may not be related to the main problem, but 7V anywhere on the car is not normal.

Voltage at the fuse holder (hot side) is ~12 V (placing the negative lead from my multimeter to the ground source for my amp). The moment I put the inline fuse in and try to measure voltage at the amp, it reads ~7V (although it has twice read ~12V, then immediately dropped to between 6 and 7 V). Fuses and that piece of power cable have been replaced (and the wire is of proper gauge), the results are the same.

As for the taillights, Locke pretty much hit the nail on the head. Check all the wiring from the taillights forward. How was the car when you got it? Was the wiring hacked to pieces, or was it basically stock?

This poor DSM was neglected and abused by it's previous owner...since I got it I have had to do a ton of stuff some expected (like timing belt - which was a shocking 4 teeth off when I got the car - amazed the car even ran, water pump, brake rotors and pads, etc), some completely due to lack of care by the previous owner (replace door handle, heater hoses, radiator, gas cap, cam seals, etc). I did have to rewire the driver's side rear brake light, but other than that the wiring in the car seems to be mostly on par with what it should be.

Also, there's a relay that controls the taillights. It'd be pretty odd for it to fail closed, but it's still worth investigating. Try removing the relay, then check the taillights. If they're off, the problem is probably the relay or the column switch. Measure the voltage at each of the contacts in the relay socket, referenced to chassis ground.

This I will definitely do first thing in the morning (along with Locke's recommendation to start chasing wires from back to front...starting with the one I rewired now that I think of it). I'm leaning towards the relay you mentioned though, primarily because of the audible "click" I heard when reconnecting the positive battery terminal today.


You guys are lifesavers...I'll be sure to update this thread as soon as I do some deeper investigating. Thanks again...

 

[VelocitàPaola]

It is not strange if his brake lights are on without any other lights on - that means his brake light circuit is activating.

Dave, I don't think his brake lights are activating, though perhaps he could take a few more steps to confirm...

...only the tail lights were on, NOT the brake lights as far as I could tell

 

[pgarland]

It is not strange if his brake lights are on without any other lights on - that means his brake light circuit is activating. Common problem on 2Gs - the plunger on the brake light switch under the dash contacts the metal plate on the brake pedal. Now for some weird as reason the exact spot where the plunger makes contact has a hole drilled in the metal plate, plugged by a plastic piece. When this plastic piece ages it will break apart opening the hole allowing the plunger to pass right through. Circuit believes the pedal is depressed regardless of actual pedal position.

Simple fix I have performed on a couple 2Gs - superglue a penny to the metal surface, covering existing hole.

Reference this thread: Team 2GNT Forum - Viewing topic #32874 - Just a heads up on our brakes....

Thanks for the heads up on that thread...I'll check it out and see if it helps solve the tail light issue...

 

[CODE4]

Dave, I don't think his brake lights are activating, though perhaps he could take a few more steps to confirm...

Very good - I did not catch that part.

OP- are the inner 4 bulbs on or all 6? Parking lights would be all bulbs, brake lights are inners. Additionally if you have a 3rd brake light that would be another way of confirming.

 

[Locke]

Voltage at the fuse holder (hot side) is ~12 V (placing the negative lead from my multimeter to the ground source for my amp). The moment I put the inline fuse in and try to measure voltage at the amp, it reads ~7V (although it has twice read ~12V, then immediately dropped to between 6 and 7 V). Fuses and That piece of power cable have been replaced (and are of proper gauge), the results are the same.

If you have a very large capacitor on your line feeding the amp, it may be causing a voltage drop at that point while the capacitor initially draws a high current to charge it.

 

[bullettdsm]

Late to the party and a lot has been covered.

I'm leaning way away from the ECU being the problem (if that gives you anypiece of mind ). I'm thinking loss of power is purely that, a line/current break within the wiring of the car (on a wire that carries power. Not a line that grounds).

You've indicated two points that don't really criss cross. The lights and the total loss of power. Like Locke, I didn't search out a schematic, but generally your lights are not intersecting with main power source (i.e. battery power) until way back at the fuse box. And since you had the problem with the lights staying on, I would suspect that something MAY be going where main power can be crossed over to the lights (and lost power can happen due to a wire short, hence checking out the fuse box).

UNLESS sometime along the way, you (or somebody else) tapped into the main power and lights somewhere, thus making another spot for shortage.

MB

 

[pgarland]

Very good - I did not catch that part.

OP- are the inner 4 bulbs on or all 6? Parking lights would be all bulbs, brake lights are inners. Additionally if you have a 3rd brake light that would be another way of confirming.

No, you may be on to something, and I will definitely confirm this morning. Problem is, I don't have the third, rear window mounted brake light, just an open (dangling in the trunk) socket to hold a bulb...for the life of me I can't figure out why, but the previous owner must not have liked having that third brake light (just like he didn't like to do maintenance on the car at all...every time I get in there I feel like I'm saving this car from the graveyard...but the body is in good shape, and it's the Oz edition GS, worth salvaging in my eyes).

Stepping on the brakes didn't change the brightness of the taillights, but my initial assumption was that since the key was out of the ignition and the light switch turned to off, that the brake lights weren't illuminating (some cars will turn their brake lights on if you step on the brake even with the ignition and light switch off, some cars won't...not sure if DSMs are of the first type, but I will definitely have my answer for that question this morning once I finish my coffee...).

I will check thoroughly this morning, and fix it with the penny trick if that is the issue with the lights. So again, thanks a ton for that information and link, I'll let you know if it solves at least the light issue.

If you have a very large capacitor on your line feeding the amp, it may be causing a voltage drop at that point while the capacitor initially draws a high current to charge it.

No capacitor...just a straight power cable from the positive terminal of the battery to the amp (with an inline fuse). Have been considering a capacitor, also why I wanted to do the saturn alternator swap, to be able to decrease load on our already weak alternator. Once I get all this figured out those two items will be next on the list of things for this car.

Late to the party and a lot has been covered.

I'm leaning way away from the ECU being the problem (if that gives you anypiece of mind ). I'm thinking loss of power is purely that, a line/current break within the wiring of the car (on a wire that carries power. Not a line that grounds).

You've indicated two points that don't really criss cross. The lights and the total loss of power. Like Locke, I didn't search out a schematic, but generally your lights are not intersecting with main power source (i.e. battery power) until way back at the fuse box. And since you had the problem with the lights staying on, I would suspect that something MAY be going where main power can be crossed over to the lights (and lost power can happen due to a wire short, hence checking out the fuse box).

UNLESS sometime along the way, you (or somebody else) tapped into the main power and lights somewhere, thus making another spot for shortage.

MB

Exactly, these points do not criss cross at all! Thats why I turned to the pros here......I know when I'm beat. Let me get to work on the lights issue, and if it turns out to be a completely separate issue, I'll update and I guess we can go from there.

Once again, thank you all a TON, I may not have to watch the rest of my hair turn gray today after all...

Will update with more information as soon as I get it.

Update:


The glue the penny trick worked (although, I had to actually superglue a penny to a nickel, then glue them both to the bracket...for some reason the penny alone was causing the brake lights to turn on and off at random...it was the brake lights, and that cheap little plastic piece behind the plunger switch had broken. Code4, many thanks for the heads up on that, it was a huge help!

As for the power surging, well I went ahead and began work re-wiring and rearranging everything that was attached to the positive terminal of my battery. My amp power cable had definitely shorted (and partially burnt up) against one of the other connections on my positive power cable. Couldn't see just how bad it was until I clipped back the amp power cable to put a new connector on the end of it...it had burnt (completely black inside the red wire) about an inch and a half back from the battery terminal...I'm surprised any voltage was getting through it at all. I had one of those short red rubber tubes covering the end of that cable, so everything looked fine until I removed the tubing and looked underneath. I decided to do the smart thing here and reattach my amp power cable to the side terminal of the battery (my battery has both top and side posts...), this way there is no chance of it shorting out on anything else as everything else is attached to the top terminal.

I'm not sure if this has solved my surging issues, but my system is back up and running (no more factory sound ). Tomorrow I plan to finish soldering a new terminal connector on my positive battery cable, then test driving the hell out of the car to see if I can get the problem to duplicate. If the problem seems to be gone, then on goes the saturn alternator, and hopefully this chapter of crazy electrical issues is closed once and for all. Wish me luck!

I will update and/or mark this thread as resolved as soon as I have verified everything. Thanks again everyone for the quick replies and the knowledgeable answers, all your help has been invaluable!

 

[95rs-420a]

I have something to add to this and was wondering if anyone might know the answer. Yesterday, my heater motor stopped working. Never had a problem with it before until now. My problem first started with the blower motor not working, followed by my dash lights cutting in and out. I also have extreme loss of power.(motor bogs) However, my parking lights and tail lights come on when I shut the car off now... Tail lights do not work when car is running nor do the dash or parking lights work anymore. (unless the car is shut off and light switch is turned to off) I too have disconnected my battery, let it sit and reconnected it after time. The problem stops powerwise for a little while and then continues. Heater fan keeps cutting in and out and if I use my rear defroster my headunit flickers on and off... Can anyone please help me or have some sort of advise for me?

 

[drawde520]

guys i also need help my 99 eclipse has problem with the taillight, side lights, and dashboad lights they wont stay on after i turn them on with the switch. when i drive and my car bounces sometimes they flicker i messed around with the switch and they flicker but the just stay off. any ideas