A couple of weeks ago I bought a Sony Ericssson car kit from someone I
know.
First time I connected it up it worked for 10 minutes then when I turned the
car off and restarted it - nothing.
Thinking I might have pulled a wire loose somehow I removed the whole thing
and retested it and it's been refusing to play nicely ever since.
To power it , there are three wires - Black for earth - Red for permanent
12v and Blue for ignition sense that needs to be connected to a switched 12v
supply.
I reconnected the power wires to the fuse box (once fuse for switched 12v
and another for permanent 12v plus a handy earth) and checked that I was
getting the correct voltages at the connector where it goes into the car
kit.
Plugged it together , switched on the ignition and nothing happened - no
signs of life. Rechecked everything - definitely getting 12v at the
connector where it goes into the car kit but it won't work.
I removed it all as I'd run out of time and then tried again a couple of
days later with the same results. Thinking this was very odd I got my
multimeter out again and measured the volatage that I was getting at the
fuse with it connected to the car kit , and with the ignition off I was
getting 12v. If I turned the ignition on so that the ingition sense has a
12v feed but didn't start the engine , the voltage on both switched and
permanent 12v lines dropped to just 5v. When I started the engine the
voltage went back up to 12v and everything started working. I've fitted a
fair few stereos in the past and never seen anything like this before - I
can't understand why the voltage should drop that much.
I didn't have time to finish off so once again I disconnected everything and
I've just come back to look at it today. I've reconnected to the fusebox and
checked that I have the correct voltages where the cable plugs into the car
kit - all good.
This is wired exactly as it was last time , but now it won't power up at all
with the engine running or not. Thinking I may be going mad I've connected
the permanent and switched 12v wires directly to the 12v feed going into the
back of the fusebox - nothing. I definitely have the power going into it but
there's no life.
That would suggest that the car kit is faulty , but just wanting to confirm
things I popped the bonnet and connected it directly to the battery and it
works just fine.
Back to the fusebox - no life , back to the battery direct - working.
Now this is a total mystery to me. It seems to vary from week to week the
situations in which it will and won't power up and I'm checking all the
connections with a multimeter and it *is* getting power. Why should it be
happy with 12v in one place and not in another?
--
Alex
"I laugh in the face of danger. Then I hide until it goes away"
www.drzoidberg.co.uk www.ebayfaq.co.uk
Hands free car kit not powering up
Hybrid Mode
