Electrical issues Rev:1

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Mjhowe29
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Electrical issues Rev:1

Post by Mjhowe29 » 13/07/18 22:52

Hi everyone.

Had an issue with a broken wire for drivers door speaker, which I mended, but speaker was very quiet compared to the others after the repair. Still... at least it worked now.
When I was installing a new head unit, I noticed that the brown wire on the stock harness looked a bit... strange. It looked like someone had bodged a splice into it. It turns out it's a splice into a cable that lines the grey sleeve that seals the power related wires for the system; it looked to messy to be factory, but it seems that indeed it is, so I left it alone.
To make this aforementioned discovery that the wire loom was like that from factory, I peeled back the black tape, and tried to move the sleeve to see what was going on, but couldn't move it far enough back, so I dismantled the plug (don't worry, I took pictures to make sure all the wires went back correctly). What I forgot to do though, was disconnect the battery. What's worse is that the key was in the acc position when the wires contacted each other when I removed the sleeve.
The car's antenna started to extend when the wires touched, and then it went back down. I put everything back together, but now my radio won't turn on (antenna doesn't extend either), my gauges work but don't light up (all warning lights etc are working) and my tail lights don't come on when I turn my headlights on. My headlight height adjuster now does nothing as well. Dimmer switch does nothing either, but everything used to work. Everything else works - entry lights, door card lights, clock, ignition barrel light, indicators (dash and exterior), headlights (but not fog, tail lights or number plate lights).
I've been on the forums here, but it seems like my problem is quite a bit different. All fuses look ok, and I replaced my amps, as according to another post on the forum, it seemed like a probable culprit for the radio problem, which was detected before the lighting issues, but no joy.

Any ideas?

I'm thinking about just going out and getting replacement fuses for the whole car - some of them are higher than the specified rating, so I should put that right anyway. I can't believe that it's a wiring fault considering so many things aren't working; I'd almost have to rewire the whole car! It's got to be something else, but I don't understand what!




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Mjhowe29
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Re: Electrical issues Rev:1

Post by Mjhowe29 » 15/07/18 13:29

Hi again everyone.

So today I replaced all of the common fuses in my car; 7.5 amp, 15 Amp, and so on, all the way up to the 30's.

Good news is I now have everything back. Bad news is, when I say everything, I mean everything except the radio system. Going to get a multimeter and start probing.

I'm going to start at the constant, switched and earth, and trace back from there.

My question is, can anyone suggest anything else? Does anyone have any idea why my radio no longer works? What could I have damaged when those wires touched?

Any help would be greatly appreciated.

Thanks :)

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abovetherim
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Re: Electrical issues Rev:1

Post by abovetherim » 15/07/18 19:20

If all the other things are back on including the Illumination circuit that's good.
Aftermarket stereos often have a fuse on the power line.
Also does your car have the active stereo with the amps mounted behind the trim on the passenger side behind the seat. Could be an issue with those.
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!


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Re: Electrical issues Rev:1

Post by Mjhowe29 » 15/07/18 20:06

Yeah, mine has the premium audio, and I have already replaced the amps.

I stupidly forgot to disconnect the battery when I removed the pins from the connector on the car's wiring loom, and all the bare pins contacted each other. The head unit wasn't connected at the time, so that should be fine. I have also tried the stock head unit for the car, and that wont turn on either, but i know both units work.

Thinking it must be a fault somewhere along the constant, switched, or ground (or any combination of these) perhaps melt damage - I don't know, but is there anything else I should try, or is this all it could be Considering i have now replaced the amp, and all fuses in the car?

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abovetherim
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Re: Electrical issues Rev:1

Post by abovetherim » 15/07/18 23:08

Do you have a multimeter?
First thing to do is check the continuity of the earth wire. If this is ok then check the 2 live wires. One is permanent live and the other is switched.
If either is showing 0v then I would check the applicable connections on the back of the fuse box.
Now I'm not sure if the switched live gets its feed from the amps though. You may have to consult a wiring diagram that can be found in a PDF of the manual known as the BGB ( big green book).
I believe shinny has a link in his signature.
1991 rev 1 T Bar n/a 3sge import. A work in progress!!!


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Mjhowe29
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Re: Electrical issues Rev:1

Post by Mjhowe29 » 16/07/18 0:04

Hi again.

Yeah, I do have a multimeter, and found the wiring diagrams easy enough. It seems that both the constant and the switched run to the power amp first via fuses, and then on to the head unit. Thanks for the advice on testing the connections at the fuse box too.

It seems that the logical thing to do, is to see what I'm getting and not getting at the harness, then check the same at the amp, and so on, all the way back to the fuses until I get to the problem.

Well, that's my day planned for tomorrow haha. Hopefully it won't be too hard to find / fix.


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Mjhowe29
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Re: Electrical issues Rev:1

Post by Mjhowe29 » 16/07/18 13:00

Ok, so I am getting 12v constant at the head unit connector, but not getting switched.

Have tested switched at the kick panel fuse, and it's ok. Looks like it's either from kick panel to amp, or amp to HU somewhere.


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Mjhowe29
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Re: Electrical issues Rev:1

Post by Mjhowe29 » 16/07/18 13:32

It appears I have been sold a dodgy amp.

I'm getting 12 constant and 12 switched to the amp, but only 0.5v from the amp (measured at amp connector).


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Mjhowe29
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Re: Electrical issues Rev:1

Post by Mjhowe29 » 16/07/18 14:06

Yep, definitely a dodgy amp. I bypassed the amp by connecting the switched in and out (grey + grey/red wires) and...

BINGO!

12v constant and switched at the HU, and the unit now powers up. I'm also getting sound, but very quiet due to bypassing the amp. The power antenna is now also working properly as well.

Just contacted seller, hopefully I'll get a replacement soon that works, and then I can put my poor car back together.

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