Urgent help needed please! Car wont start

[GarethM]

Not my car but my brothers Megane 1.4 53 plate,

he was trying to jump start his 306 diesel as the battery was flat, had the megane engine running, went to connect the jump leads to the megane and as he did the megane died!

All dash lights, exterior lights, wipers, radio etc work, but the car itself wont turn over at all.

Any ideas? fuses? or something more serious?

 

[Nicolasticity]

Had a battery die on a Clio in similar circumstances. Working fine one second and then nothing. New battery everything was OK

 

[Justin]

Sounds like a popped fuse.. I'm probably wrong

 

[GarethM]

thats what i said, im guessing it'll be one of the fuses from the engine bay?

 

[Da]

Did he short the leads out?
Did he connect them to the 306 or not get that far?

Personally I would never try and jump start a diesel car from a petrol car as diesels have far higher cranking current.

If he connected the leads he's probably fried the Meggy's battery.

 

[GarethM]

he connected them to the 306 first, then the megane. the back wiper works but not the fronts, so could be battery and fuses?

 

[Da]

Did he try and start the 306 or did it die before hand?

He could have blown fuses yeah, it's unlikely though.

First thing to try is a new battery.

 

[GarethM]

no as soon as he put the leads on the megane it died! comes up with electrical fault on the dash now?

ill ask him to check the battery and fuses, cheers

 

[Alastair.]

blown uch or injection computer i expect.

 

[Da]

I didn't want to mention that

 

[GarethM]

is that expensive? hard to change?

whats the UCH?

 

[Da]

Universal Control Hub and yes, it's expensive as it's locked to the ECU. Basically it controls all of the none esential electrical equipment, like wipers for instance.

 

[bmh.01]

blown uch or injection computer i expect.

I'll go with that, never never never jump start a modern car off another or vise versa. Booster pack or take the battery off and charge it seperately.

Seen a few meganes killed like this now, including one I wanted to buy :dapprove:.

Expensive lesson coming up methinks.

 

[GarethM]

lol how expensive are we talking?

 

[Da]

Brandnew, guesstimate £300 - £500

 

[GarethM]

ouch! unlucky i guess

 

[Trev_m]

Check the uch fuses in the fuse box before you start throwing loads of money at it.

 

[Tunst]

did he put the leads on the correct terminals pos to pos neg to neg?
my mate made the mistake of putting pos to neg and neg to pos killed the battery and fucked the ECU was an expencive mistake ecu for a 08 330d aint cheap :dapprove:

 

[GarethM]

he said he cant remember mate, which makes me think he did.

ill ask him see if he's had a look at it today