2G *SOLVED* Electrical issues, horn blows when headlights turned on ect

[TurboSpider]

I have a 97 spyder gst which exhibits some odd behavior. The battery cables where they go to the alternator post came out of their ring terminal so I got a new ring terminal and crimped it on. Everything was fine and I drove the car a couple times. Then when parking the car it started acting strange. First thing I noticed is that when I went to lock the doors with the remote, nothing happened. I tried the power door lock switch on either door and nothing worked. When I turned the headlights on the horn blared constantly. Not a beep beep sound like an alarm but just constant blaring. I pulled the battery cable off quickly which admittantly is loose enough to be able to just pull off, but it has been that way for some time. I noticed that when I put the battery cable back on, that the headlights and foglights came on regardless of the headlight switch being in the off position. Futher testing noted my heater wasn't working, I had no interior lights. Once again, everytime I would turn the headlights on or even just quick honk the horn, the horn would just contstantly blare. I pulled the horn fuse in hopes I would make it home.

I was barely even out of the parking lot and I saw the voltage dropping rather quickly on my volt gauge. Sure enough I pulled over and the car died. Had the car towed home and started looking at it. Recharged the battery and it was still doing the same thing, as soon as I hooked the battery terminal up, headlights and foglights came on by themselves.

Tried jiggling wiring around the alternator thinking maybe I knocked something loose when I was down there, seemed to make no difference. Then I noticed the new terminal end I crimped on to the battery was hitting the alternator case. I did have electrical tape wrapped around this connector, however it worn away in one little spot allowing the ring terminal to make contact with the alternator casing in one spot. Further investigation I found a blown 100 amp alternator fuse under the junction box under the hood.

I am assuming it all started with the battery wire shorting out against the alternator casing. This blew the alt fuse which is why the vehicle stopped charging. The question I have, is what else is wrong with the car. I would imagine a blown alternator fuse wouldn't cause the horn to honk constantly when the headlights are turned on, door locks, windows ect to not work. It seems this short took something else out or possibly melted wires somewhere. Any idea where to start looking? My one friend suggested the body control module is now bad. I do have a electric service manual and cannot find any body control module anywhere. Maybe it is part of the ECM and I fried the ECM? I plan on pulling all the fuses under the dash to see if I see anything blown. Any suggestions otherwise where to start looking at what is damaged?

 

[91talonts1]

Sounds like you grounded the power wire from the alt out and melted some wires together. I've never seen a body control module in a dsm and I've been through every harness in my car so I don't think that's what you're looking for.

 

[TurboSpider]

That is a good suggestion, it looks like there is two white wires which go to the alternator which come of a large wiring harness. Guess I will have to pull the tape and protective plastic sheathing off that wiring harness and see where the wires go and see if there is anything melted in there

 

[Kryndon]

I swear these electrical gremlins are so annoying! I literally just closed my electrical manual from reading about another issue, but here's what I can tell you about yours:

I once had the horn get stuck in a constant beeeeeeeeeeep like you're describing. I simply pressed the horn button once and there it went. I changed both the horn fuse in the engine compartment AND the fuse in the footwell, but it didn't fix it. I unplugged the two horn wires (I don't have the plug) for awhile. Later on, I decided to reconnect them. One day, it was really hot and blazing outside, I came to my car and it started flashing the lights, beeping the horn and all that jazz. The alarm was going off from the heat, and the neighbor said it had happened at least 10 times during the past few days. So I disconnected the alarm and horn altogether. By alarm, I mean the little pressure switch which gets triggered by closing the front hood. My (SECURITY) light and module still works and lights up.

Fast forward to today, I was replacing my clock spring (behind the steering wheel), and I reconnected my horn and finally it works whenever I press the button without it going off in a constant blaring.

Additionally, I also experienced the situation where the Security system did not arm after locking the doors, and the central locking also stopped working. That was fixed by fixing a broken wire to the driver side door switch (the little pressure switch where the door meets the chassis), as well as unplugging the security module connector which is located near that pressure switch, behind the rear left interior panel. After unplugging it, you plug it back on, close all doors and use your key fob to lock the car, which should trigger the green (SECURITY) light.

As for your alternator, when I got the car it was actually missing the 4 wire gray connector that goes into it. It took me a day to realize it was missing, which made me almost drain my battery completely. I experienced quite a few weird issues from essentially not having an alternator. So I suggest you trace back the 4 wires and make sure they are intact and properly connected. The reference page for this on the DSM Electrical Manual is "8-102". I can send you a picture of it if you can't find it.

 

[TurboSpider]

Even with the manual, I am having a hard time understanding it. I am leaning towards the melted wires issue, seems to make sense. Also if I am reading and understanding the manual correctly, the alternator fuse under the hook 100 amp also sends power to the door locks and windows at fusible links 2 & 9 which is probably why the door locks, interior lights, windows and everything doesn't work. I can't seem to find which wires run in the harness along with the 2 alternator battery wires. If there is horn and headlights/foglights wiring running through there, it could make sense that there is something melted in there causing the horn to sound with the headlights being turned on ect

 

[Kryndon]

I'm not ruling out the possible melting of two wires, but I'd suggest you focus on the alarm system first. Especially if you still have the factory alarm. The headlights, hazards and horn are all meant to go off simultaneously when the alarm is triggered. Check those pressure switches I was talking about and maybe even try disconnecting them and trying out your horn.

 

[91talonts1]

^ Good point. I didn't even consider the alarm I've never had one. I would definitely check that first before tearing into the harness.

 

[TurboSpider]

Ok guys, I am still at work but I decided to do another search. Basically typed in headlights turn horn on dsm tuners and found about 2 or 3 threads that came up with people having the exact same issue as mine. All problems started after shorting out the batter wire at the alternator, normally with a wrench when replacing it. One guy said that when he turned his headlights on, his horn would blare, also his windows, interior lights ect were not working. Exactly like mine, exact same symptoms. He also stated that he was working on the car and shorted out the alternator battery wire. Someone told him to replace the alternator/choke fuse. He did and all his issues went away. It sounds almost impossible that a blown fuse could cause so many issues but there is multiple threads I just uncovered here at work that all have similar issue with just the fuse repairing the issues.

I anxiously will try replacing the alternator fuse as soon as I get home and see if my problems go away.

Just can't wrap my head around how a fuse could cause these issues. From the door locks, windows, heater, ect not working it makes sense, as apparently that fuse also allows power to get to the fuse block inside the car. If that fuse is blown, the fuse block @ fusible links 2 & 9 are not getting power thus why the windows, door, locks ect don't work. That makes perfect sense there. But why the heck does a blown fuse cause a horn to blare constantly when the headlights are turned on? Only thing I can think of is that the lack of power from the fuse is causing some kind of power disruption at the relay for the horn and headlights and causing them to feed off each other?!? That could be completely wrong also. Either way, I will let everyone else know what I find when I get home and pop that new fuse in.

Here is some old threads I dug up where it looks like the alternator fuse caused issues similar to mine. Hopefully these are of help to someone in a similar situation as mine.

https://www.dsmtuners.com/threads/resolved-headlights-and-horn-wont-turn-off.299976/
https://www.dsmtuners.com/threads/h...ndows-power-seats-fan-not-working-hel.304120/
https://www.dsmtuners.com/threads/headlights-turn-on-horn.182500/

 

[Kryndon]

Actually you just reminded me that I did also had to replace my alternator fuse, TWICE! First time was with a 120 amp unit which was the wrong amperage, the second time with a standard 100 amp one, so that may or may not have helped me with my own similar issues! Many systems can go through the same fuse, but when it comes to electricity I can only just guess what's happening and why. Keep prodding the problem until it gets fixed, I guess

Do let us know after you change that fuse, and make sure it's the 100 Amp one!

 

[TurboSpider]

Solved! replacing the alternator fuse fixed everything. Weird how a blown fuse can cause those strange issues with the headlights and horn but sure enough thats all it was. Put the new 100 amp fuse in and everything is working correctly now.

Thanks everyone who gave suggestions for this thread.