Dead car - battery polarity reversed

[Dave]

When trying to start the car from another battery having managed to drain the car's battery, I managed to connected the 'donor battery' backwards (yes, I know. Long story). Result - completely dead car.

 

I fear the worst and that this may be terminal or will have caused extensive /expensive damage.  Will this be the case or is there anything I can look at initially?

[Livibob]

There is apparently a main fuse on the positive battery cable. See another thread for information (Wired the starter battery in the wrong polarity popped fuses)

[Picasso]

hello dave can you pm me your reg no. or vin i will send you a picture where the fuse located and part no. i help lots of members with part no.s

[Dave]

Thank you very much for your replies.

 

I've just put the original battery back in having been charging it - it was whilst charging it that I thought I'd killed the car with a different, incorrectly connected battery - and was about to lock up and leave it, probably for a long time, I imagined.  Of course, I had one more go first, and on turning the key all the usual lights lit up and it started.

 

I've no idea what's going on. It was completey dead on a good battery earlier.  Anyway, I'm just glad it's alive again and will not be so careless again.

 

Thanks again.

[Clutha]

57 minutes ago, Livibob said:

There is apparently a main fuse on the positive battery cable. See another thread for information (Wired the starter battery in the wrong polarity popped fuses)

 

[Picasso]

glad all sorted dave.

[dezufo]

21 hours ago, Dave said:

Thank you very much for your replies.

 

I've just put the original battery back in having been charging it - it was whilst charging it that I thought I'd killed the car with a different, incorrectly connected battery - and was about to lock up and leave it, probably for a long time, I imagined.  Of course, I had one more go first, and on turning the key all the usual lights lit up and it started.

 

I've no idea what's going on. It was completey dead on a good battery earlier.  Anyway, I'm just glad it's alive again and will not be so careless again.

 

Thanks again.

You will now have to reset the windows so you can operate them from the drivers' door switches. Go to each door and lower the window halfway down then take it all the way up and hold the switch for 2seconds

[Dave]

1 minute ago, dezufo said:

You will now have to reset the windows so you can operate them from the drivers' door switches. Go to each door and lower the window halfway down then take it all the way up and hold the switch for 2seconds

 

[Dave]

Yes - I discovered the window issue yesterday and found a helpful video:

 

[Rojie]

On 8/19/2025 at 3:35 PM, Dave said:

Thank you very much for your replies.

 

I've just put the original battery back in having been charging it - it was whilst charging it that I thought I'd killed the car with a different, incorrectly connected battery - and was about to lock up and leave it, probably for a long time, I imagined.  Of course, I had one more go first, and on turning the key all the usual lights lit up and it started.

 

I've no idea what's going on. It was completey dead on a good battery earlier.  Anyway, I'm just glad it's alive again and will not be so careless again.

 

Thanks again.

 

You need to check the battery terminals for oxidation and tightness, at both ends of both leads.

[Clutha]

11 hours ago, Rojie said:

 

You need to check the battery terminals for oxidation and tightness, at both ends of both leads.

Agreed, a slight movement in an ‘eye’  connector stopped mine. Just moving it slightly was enough to get a start.