HELP! Reconnected battery, now horn won't stop blowing constantly and car won't start

[Tunemanjjw]

HELP!

2006 mazdaspeed 6 sport (basic) model

Symptom: When battery terminal is reconnected, Horn blows continuously (no pulsing) and all turn signals are lit solid, instrument panel does not light up, car does not respond to key fob commands or key in the ignition (car does not start consequently), interior lights no go, power windows no go, low beams will not turn on, HIGH BEAMS WILL TURN ON.

Backstory: I removed my battery to tighten up my turbo inlet hose, and when I reconnected the battery there was a lot of constant sparking instead of the usual single spark. I cleaned up the terminal some and when I went to connect it, as soon as the terminal touched, the above symptoms go on until it is unplugged. Also notable, the key was in the ignition in the II position (right before cranking position) the entire time. I've not had any electrical problems with this car EVER. There are no aftermarket alarms or such installed on my car.

What I've tried: I've tried cranking the car with the key in the ignition (this is the normal key, not the valet key), pressing and or holding any combination of buttons on the key fob, the interior light and instrument panel fuses had blown so I tried replacing those, they reblew and no difference.

Curious Angles: did my car think it was getting stolen since the battery was reconnected while the key was in the ignition in the next-to-start position -- is this what is supposed to happen given the circumstances? Did having my key in the ignition II position when I reconnected the battery fry the chip in it making it invalid and henceforth my car does not respond to it?

Is there anything I should try, or does anyone have any light to shed on this? Being my only car, it's going to the dealer sometime tomorrow to address this but I'd love to save some pesos and time if there's a slick fix or suggestion. Thanks

[i8urgti]

holy jebus wtf did you do? that sounds like VW problems. nothing i can offer except good luck

[Tunemanjjw]

Don't I wish I knew! Totally bizarre. All
I can think of is some weird ecu/immobilizer response (since I'm not familiar with the effects of making it seem like I am stealing my own car or how to
Blow the chip inside the fob) or maybe when I was tooling around in the engine bay I jammed a wire or harness or something...I didnt brute force anything or stretch any wires doing the TIH tightening so I have no idea! No major surgery here.

[eppopipe]

It sounds like what would happen if you put the terminals on backwards.
Could have nuked the ECU. Take the battery off and disconnect the ECU harness, Drain the whole system and then try hooking it back up. Report back.

[Sid3wayS]

Your first problem is that you left all the electronics and pumps on while you disconected the battery... Would you just pull the cord mid way threw the boot up of your desktop? Your secound problem is that like @eppopipe said it sounds like you reversed the terminals. Like he said drain the ecu fully and keep your fingers crossed that you didnt fry anything. Good luck and if you figure it out post it on here.

[MZR165]

There is no slick fix...you've shorted something by leaving the key in the next-to-on position while disconnecting and reconnecting the battery and or by possibly crossing the cables on reconnect. Take it to Mazda...this could be expensive. Sorry.

[Spirry]

+1 on the static discharge. Disconnect the battery cables. Touch the two leads together for a few seconds. Wait 10-15 minutes. Reconnect battery cables.

Doubt that will work but give it a try. Just make sure the battery is not connected to anything during the process.

Also, you probably damaged something with a voltage surge...

[Raider]

If reversed terminal syndrome, the main fuse should have popped, and one of the terminals would have been tough to connect to.

The issue was key on when you disco'd, and that fried something up, as everyone ^ has posted. Keep us posted on what the dealer finds out Might need a $100 ECU reflash to fix it, minimum.

[Tunemanjjw]

So the terminals were def not connected backwards. I have distinctly different terminals for - and + but I see how this seems like a similarly resultant scenario.

Where do I disconnect the ECU (I haven't tinkered much with this car)

I have disconnected the battery and pumped the brakes several times to drain system and retried with no difference.

[Sid3wayS]

The ecu is the 2 big plugs write next to the battery. Each one pops off seperatly by lifting the lever. But if u already drained the battery n no result its likely you fried something. Sorry bro

[H3llfir3]

its the BCM located in the drivers side cabin fusebox. You more than likely shorted it out.

[crazyp]

A friend of mine has an RX8 that did this when we jumped his car. turned out to be an alarm feature. was the door open and ignition on when you installed the battery?

close and lock doors
install batteries.
unlock door with remote

[chuckms6]

before you get in too deep check ALL fuses and grounds, no matter if you think they are related to the problem or not. sometimes the way a system is wired may cause voltage to backfeed through another unrelated circuit to find ground if its specific fuse is blown. after that and replacing all the blown fuses if there are any disconnect the battery for a while and let the system drain as previously discussed. if you still have problems, THEN take it to the dealership.

[captain slow]

I wanna be helpful and an asshole all at the same time. I mean come on, why was the key in the ignition and why was it turned to on???? Try all the previously mentioned things. Other than that, I don't think we can help you here....

[Tomas]

you could disconnect the horn for a start. At least you won;t go deaf diagnosing the problem. lol

[3mazdaspeed]

My neighbor had the same problem after her battery died, her husband told her to just drive it around till it stopped. Well she did and it worked out for her.

[superskaterxes]

check your body control module at the drivers footwell. i had the same thing happen to me.

[_riskibus_MS3]

poltergeist

[Mistersix]

Originally Posted by superskaterxes check your body control module at the drivers footwell. i had the same thing happen to me.

I'm having the same issue after installing tail lights after a paint job. I crossed something and got a short and the horn blares and 4 ways blink etc. What ended up being the fix for you? How do you check the bcm?

[teddy]

Hi guys,
I have a similar problem: I just replaced the battery on my 2006 Mazda3 GT and when re-connected, all lights and horn are solid on. Everything else is dead. No dashboard light, nothing... I tried to open the trunk with the key - it didn't work. I tried open-close/open-close sequence on the driver's door with the key. Doesn't work. I tried to put the key in on position and then re-connect the battery: doesn't work either. But, in this case, with the battery still connected, I turn the key to off position and now the wipers stopped.
Can anybody help me with some ideas...?
Kindly appreciated!

[thehead]

to turn off the alarm, you stick your key into the driver's door, and turn the key to the unlock position until it stops.

[teddy]

tried that, it didn't work... ;(

[teddy]

I also found that the "ROOM" fuse is blowing up each time I re-connect the battery.

[hza47]

BUMP

Has anyone had any luck figuring out this issue?

[Say Chi Sin Lo]

Sorry to laugh, but this sounds like something the guys at the (old) Top Gear would do. Hahahahaha

[sh4d0w]

O.K. So obviously something is shorting out that's on the room circuit. Disconnect everything that runs in the room circuit one at a time until the room fuse doesn't blow when you turn the key on. Might cost you a bit in fuses but at least you should end up finding the issue.

Or just disconnect everything that runs on the fuse and just start connecting things one at a time until it blows. This is prolly cheaper lol.

lol i'm answering a 2 year old question nice.