Electrical problem... resolved. by calibrax

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Had a bit of a nightmare today, which COULD have ruined my Christmas! (it's a happy ending though!)

For the last week or so, my stereo in the car has switched itself off and on momentarily, just once in a while, while driving. Which I assumed was probably one of the plugs behind the stereo not seated properly. No big deal. Added to my list of 'jobs to do'.

Then, the day before yesterday while leaving work I stopped at a roundabout, and the car cut out completely. I thought it had stalled, restarted it and everything seemed fine. I just put it down to the cold weather.

Today I left work at lunchtime to head home, got about half a mile, and the car died. No power at all. Got onto the hard shoulder of the M23 spur road, and my first thought was to check plenums. Had a look... dry as a bone. Nothing looked out of place. Got back in the car and called the AA. While I was waiting, suddenly the power came back! Started the car and let it run for a bit. Ran fine, but the display would flicker slightly whenever I pressed any switches, as if there was a lack of power. Scangauge was showing 14.2v though, so alternator was fine, and the battery is only a few months old. Then suddenly the message centre flashed up low oil pressure, and low battery... [EP] appeared on the display... then the engine died again!

This went on for a bit... it kept coming back to life, and dying again.

The AA bloke turns up, and I'm behind the wheel while he's fiddling with the underbonnet fusebox checking the relays and fuses. Suddenly, power returns, then goes again, then returns... ah ha!! the problem is definitely in that area.

Anyway... it turned out to be a bad connection on the wire which runs directly between the battery and the underbonnet fusebox. Confirmed this by wiggling the wire! He cleaned up the connections and bolted it back on, and now it's running perfectly.

I have breakdown repair cover with the AA, so if it had been something expensive it wouldn't have been a problem, but obviously with Christmas so near the timing was awful... especially as I have a 230 mile trip up to my parents to do tomorrow! I'm very, very relieved it was a nice simple problem and easy to fix.

Merry Xmas everyone! :mrgreen:

2004 MG ZT+ CDTi 135


Posted 23 Dec 2010, 20:28 #1 

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Thanks for posting this.

It's always useful to have explanations to these odd ones, as it can save a lot of head scratching if it ever happens again.

Posted 24 Dec 2010, 10:43 #2