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View Full Version : Radio wiring mangling = fried ECU? [solved]



timhortons
10-12-2010, 04:59 AM
Alright guys, the other day I posted pictures of the 1999 Legacy I just got hold of... but there's a problem, a big problem, that just happened.

Okay I'm going to rewrite to try and explain better what has happened...

I went out to the car earlier because I was planning on keeping the deck it has in it, so I innocently went out to play with it a little and go through some of it's settings. I probably shouldn't have, and I probably shouldn't have had the key in the ON position *doh*

So I'm playing with the radio, .. with the key on, and then all of a sudden the radio goes out, powers off. Uh oh. So then I check the ignition, i go OFF to back ON and then the radio comes on, but then all on it's own without my touching anything it goes off right away, then on again, then off in this cycle. So I again, I turned the key OFF...

I pulled the radio out, and the wiring is mostly okay, except for a couple wires here and there that aren't connected to anything, and none of them are capped, they come out from the radio but don't go anywhere, there are two gray ones, a couple of white ones and an orange one. They dont have exposed wires, but they've just been snipped and left like that.

So, I d/c the radio all together, took out the fuse to the radio and turn the ignition to ON... the check engine light came on, but then also a new light, the ABS light. Then they both go out, but stay dimly lit. I went to start the car, and nothing, it wouldnt start. All I could hear is the clicking of a relay, no starter motor or anything.

I disconnected the battery for a while and then reconnected it to try the key again, it behaved normally except for dim-lit warning lights, not entirely out, and so I went to start it and then still nothing, but then when releasing the key but still ON the CEL flashed in rapid succession, and I could hear a relay doing the same with the CEL.

Where it is right now: the CEL light and other lights like ABS light dont even come on now, I highly doubt it's the bulbs, the oil light, seatbelt light, door open lights come on (all the stuff not related to the ECU seems to be working right). Turning the key to the START position now yields nothing, no clicks of relays or anything, obvious if the CEL isn't working.

I'm also noticing now that the key door locks dont seem to be locking and releasing very "strongly" and the lights were dim, so I measured the battery and it reads 10v or so, not surprising really since it hasn't been running, and I've had doors open and such, but despite the low battery reading I would expect more action out of the car when trying to start it.

To be honest, I think I already know where this is going, it really seems like the ECU got shorted somehow. I'm leaving the radio fuse out and the deck out of the car now until I get some advice or find out what the problem could be.

I guess I shouldn't have been playing with the radio with the key in the ON position! I guess I missed the ACC position or something that might have saved the ECU as it wouldn't have been initialized.

If i didnt mention before, it was wired up for amps and speakers in the trunk, the only wires that were connected at the time were the audio lines, none of the power lines in the trunk were live, but they're all dead-end wires right now, so I probably should have been more cautious about playing with the radio without checking it more... oh well, hindsight.

Anyways, if you have any other ideas to determine if it is in fact the ECU, which it probably is, or if something else could have shorted along the way to produce these symptoms. I find it hard to believe the ECU is that delicate, but who knows. Like I say, none of the fuses I've checked are blown.. the radio must have caused it because it was all working FINE until the radio went all crazy.

Huffer
10-12-2010, 07:02 AM
Have your battery checked but it sounds like all you did was run it flat.

timhortons
10-12-2010, 07:10 AM
Well after I saw the battery at 10v I thought... hmmmmmm, maybe it is just the battery.

but really? all this weird activity just because the battery is a little low?

if thats all this is then i'll be happy, but i've never seen a low battery make a car act so funny, i'm hoping. we'll see when the battery is back to 12v

timhortons
10-12-2010, 09:32 AM
Heh, alright, battery is back up, and guess what, IT WORKS, lol.

Now I feel silly, I got myself quite worked up over a low battery, but the timing of everything and the behavior made me a little uneasy!

That just goes to show how vital a good battery + charge is to some cars... goodness. I guess I was also a little worried, because, you know, whenever you see wires all over the place and things have been modified and you don't know whos done it or when it was done it can raise additional questions and make you jump to conclusions when it was something obvious to begin with.

Huffer
10-12-2010, 09:45 AM
I pulled the radio out, and the wiring is mostly okay, except for a couple wires here and there that aren't connected to anything, and none of them are capped, they come out from the radio but don't go anywhere, there are two gray ones, a couple of white ones and an orange one. They dont have exposed wires, but they've just been snipped and left like that.

These are likely to be speaker sends and a subwoofer. You should wrap these up in electrical tape to prevent grounding out.

timhortons
10-12-2010, 12:53 PM
I pulled the radio out, and the wiring is mostly okay, except for a couple wires here and there that aren't connected to anything, and none of them are capped, they come out from the radio but don't go anywhere, there are two gray ones, a couple of white ones and an orange one. They dont have exposed wires, but they've just been snipped and left like that.

These are likely to be speaker sends and a subwoofer. You should wrap these up in electrical tape to prevent grounding out.

As it turns out, four of the wires were in fact for speakers, and they were for the door speakers, which the previous owner had re-routed to the system he had in the back. When they removed it I guess they didn't bother wiring back up to work without whatever was in the trunk.

I can tell you right now though whoever did this setup was actually pretty decent with it all, they used heavy gauge wire for the amps and appropriate gauges everywhere else, but it's kind of funny they left the speaker sends snipped off and dangling around in there.

I think I ran the battery down again listening to music in full six speaker glory, it actually is quite a decent system even without the stuff the previous owner had in the back, so I'm going to keep the deck and run it as is, no reason to change it right now! There's still an unused wire coming from the deck, but when i measured it's voltage it was around 2-3v, low in comparison to the 5v the speaker sends put out. None the less I've taped it all up, so I don't have to worry about it now.

I'm relieved, and happy it's working, I can cross one thing of my "todo" list, well, almost, it still needs a new 12v cig lighter put in.

Thanks for the replies and advice!

Huffer
10-12-2010, 04:12 PM
it still needs a new 12v cig lighter put in.

Ah yes, something I need to do also. Am thinking of just installing an inverter and having it put out 110v.

timhortons
10-12-2010, 06:42 PM
it still needs a new 12v cig lighter put in.

Ah yes, something I need to do also. Am thinking of just installing an inverter and having it put out 110v.

I am so tempted to do that too actually, makes more sense in some ways, then you're not limited to stupid adapters designed for the lighter plug, which really was never meant to be used to power devices anyways. They always seem to get warm when powering something, I've noticed the plugs for the cig-lighter have yellowed and look more brittle, in a "heat damaged" sort of way.

It would be kind of interesting to put a 110v fused outlet near or in place of the cig-lighter, but I'm not sure I want a 110v socket that close to a frequently used area, it would be accessible though :\ actually, I'm sure one must exist that is fused and has a "flap" on it which would protect it when something isnt plugged in (one that isn't hideously ugly or could be made to look like it fits in)