Don't like the adverts?  Click here to remove them

Jump Start mess up

Grease Monkey

New Member
Joined
Aug 5, 2010
Messages
27
I have 2005 3l d4d, had a flat battery, starter solenoid clicking but not turning over, and asked a friend for a jump start. I connected the leads to one of my batteries and my friend then connected his.
Unfortunately he connected his the wrong way round. Immediately of there was a flash from his battery and both my indicators came on. I pulled of the crocodile clip on my battery.
With the clips on the correct way the panel lights all came up but when trying to start there was no click from the solenoid.
I checked the batteries and one of them was way down so I replaced it. Trying to start again there was no click from the solenoid.
The big question is how much has been messed up? Could it be the immobiliser, starter relay or something else?
Any advice would be appreciated.
 
Reverse polarity is usually an expensive mistake!

Modern jump start packs are a better option than a friend because they usually protect against reverse polarity.

First thing to check is all the fuses, and hope it's just a cheap fuse that's blown!
 
Does anything work?

Does the instrument cluster light up?

Does the glow plug light come on?

Do the lights work?

Looks like AM1 (fuse 56) and AM2 (position 62) - located in the engine bay fuse box would be the first ones to check.
 
Don't like the adverts?  Click here to remove them
Known this happen on older Mercs, generally it blows the overvoltage protection relay which protects the rest of the system.

Whether there's an equivalent type of thing on our vehicles haven't a clue.
 
Instruments light up
Glow plug lights up, I don't think it did before
Have not checked the lights.
I only changed the 1 battery because they are not that old, Exide.
 
Just remembered i was daft enough to trust someone else connecting up.

Few years ago, cold spell like this a Polish bloke worked at our place at the time, couldn't start his Corsa just clicking, i offered a jump start and got my end connected but he got it wrong his end with a sizeable flash, luckily seemed to be no damage, certainly not to my 120, however it still wouldn't turn over...by now i guessed it and i bet you lot have too...asked him if he'd got enough anti freeze in the system...cue blank look...yep engine locked solid...cue me coiling up my jump leads and buggering off home cursing myself for once again trusting someone else to have any common sense, could have been an expensive mistake, mate of mine blew the digital dash in his Laguna jump starting a friend to the tune of £500 worth of damage in the 90's.

Unusual for east european blokes to be so not mechanically minded, usually they're pretty hot on cars.
 
Have not been able to get back to the car, It's a few miles away from where I live and no public transport. Hope to get there with a lift on Saturday, fingers crossed.
 
Couldn't find the fuses mentioned, these are photos of the fuse box
The lights work but not the front or rear wipers
 

Attachments

  • Engine fuse box.jpg
    Engine fuse box.jpg
    418.6 KB · Views: 35
  • Fuse cover.jpg
    Fuse cover.jpg
    340.7 KB · Views: 30
Hmmm...

I've circled am1 and am2. Could be any of them that's blown though - can you get a multimeter and give them all a quick check?

I think there might be a starter relay too, it's too dark for me to check now but I think it's in a separate relay box next to the fuse box.

But check all the fuses first if you can, including those in the drivers side fuse box
 

Attachments

  • Screenshot_20221209_175333_Chrome.jpg
    Screenshot_20221209_175333_Chrome.jpg
    451.6 KB · Views: 33
Hmm, wipers! Front and rear are on different fuses, but from what I can see on the wiring diagram, they get their feed from the ignition switch.

Which gets its feed via ALT and AM1. ALT is a big 140A fuse - its on your diagram, looks like its yellow/orange'ish in the pic, top left.

Check AM1 first, because a load of other stuff goes through the ALT one, and you seem to have some things still working!
 
Good advice from Karl.
One other thing, if any of the relays are same size/rating, try swapping them around to try and eliminate any blown one/s. Mark them so you know which you have swapped where, and try to start each time you swap so you know where the problem may be.
While you're there, with ignition off, remove them one at a time to check if there is any melting, charring or poor connections on underside of them
 
I'd test the fuses before the relays, as they're (hopefully) more likely to blow first. For the small fuses, put your multmeter on continuity and use the two pins accessible in the top of the fuse. You can do this without taking the fuses out. (If your meter doesnt have a continuity setting, use resistance (ohms) and expect to get 0 ohms for a good fuse). The bigger fuses probably wont have any testing pins accessible, so you'll need to take them out to test them. The top on those fuses is clear, so you should be able to visually check if they are OK or not.

To test relays its a bit more complicated, but assuming a simple one switched circuit NO relay (4 pin), you want to check for some resistance across the coil. An infinite resistance there (open circuit) means its broken. Also check for open circuit across the switched high-current pins. You can go further and energise the coil with 12V and check you get continuity on the high current switched pins.

There will be loads of stuff online about it if you need more detail.
 
Back
Top