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Intermitant electrical issues

Posted: Tue Oct 06, 2015 7:20 pm
by original89
Have an intermittent electrical issue if anyone is able to help.
Basically the battery runs flat.
Never happened until I installed an SE wind blocker with the stock speakers in, I wired these to the rear speaker outputs of an after market head unit. I have an amp running with the 4 genuine headrest speakers paralleled to an amp, and two door speakers also to the amp.
I had this disconnected for a while due to the battery running flat, and it seemed to stop the issue of the battery running dead, however I'm unsure if this is the cause.
Ever since installing the wind blocker speakers (even when it was disconnected) I have an intermittent parker lights issue, they turn on on their own accord for no reason, but most commonly when indicating.
No idea where to start, open to any advice. It's a 1989 NA.
Thanks in advance...

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:04 pm
by Magpie
Where is the amp getting its power from? It sounds like it is from an always on source, that is direct to the battery and not controlled by the ignition.

Was there any drilling when you installed the SE wind blocker?

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:07 pm
by original89
The amp draws its power directly from the battery. There is a signal wore from the hesdunit to the amp which tells it when to turn on, this signal is only sent when the accessories are on or the car is started. The amp does turn off when the keys are out, so it isn't the issue, supposedly..
I also never had any problems until adding in the wind blocker speakers so it shouldn't be the amp
No drilling

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:12 pm
by bruce
You have obviously wired it wrong. Recheck everything as something is staying on. Like people have said, I'd say the amp is staying on (how can it switch off if wired direct to the battery?)

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:17 pm
by original89
The amp has an on light. that switches off when the car is off, on when it is on, I do imagine it is staying on if the light is off. It turns on and off by the signal wire from the head unit that gives it the direction to be on or off.

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:32 pm
by Nevyn72
original89 wrote:The amp has an on light. that switches off when the car is off, on when it is on, I do imagine it is staying on if the light is off. It turns on and off by the signal wire from the head unit that gives it the direction to be on or off.

I suspect the amp is still drawing some power.

The light is more likely indicating active/inactive rather than fully shut/powered down.
If disconnecting the amp appeared to solve the problem previously, you've got a fairly good indication that's where the issue is.....

Try fitting a relay activated by the ignition circuit for the power supply and use the accessories supply for the on/off trigger. :wink:

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:35 pm
by original89
Thanks mate, I'll give that a shot!

Re: Intermitant electrical issues

Posted: Tue Oct 06, 2015 8:38 pm
by Magpie
Simple test is to get a multimeter and test for voltage when it should be off. The simple fact of disconnecting it and no more parasitic loss says simply it is not powering off.

The issue could also be the head unit being always on and ready to give the signal to wake the amp up. Again when there is no amp there is nothing to signal.

However I'm no auto electrician or car stereo expert. I solved the issue by removing the stereo, speakers, carpet, replacing the battery with a lithium over net 50 kgs of weight removed, that includes adding a roll bar and hardtop!

Re: Intermitant electrical issues

Posted: Wed Oct 07, 2015 3:10 pm
by Roadrunner
original89 wrote: I have an intermittent parker lights issue, they turn on on their own accord for no reason, but most commonly when indicating.


From what you have described the amp is connected properly. I'd also be looking into your parker light issue. What's the chances the parkers are randomly turning on over night/when your away from the car. That will drain your battery in no time (ask me how I know)
But much easier and wiser to first rule out the stereo and amp as others have suggested.

Re: Intermitant electrical issues

Posted: Wed Oct 07, 2015 3:39 pm
by cookie
I had issues with the stalk at the steering wheel causing highbeams to come on randomly. Possibly the parkers switch is a bit funky? Amp sounds like it's connected fine but possibly an internal fault.

Re: Intermitant electrical issues

Posted: Wed Oct 07, 2015 3:49 pm
by Magpie