Z4M no start no dash lights, advice requested

calcerr · 05-01-2015, 09:13 AM

Hi everyone,

Newbie in the forum here. I bought few months ago a 2007 Z4M coupe, which has developed a simple-looking, but (for me) vexing issue.

The car is parked for longish periods, as I don’t drive daily. So I come back to it after several weeks, and find that there is zero battery power, no dash lights and no systems at all. I thought the battery was dead, and once I saw it was lead acid, I hurried to change it with an AGM H6. I did not test the old battery, which was a bit stupid.

Anyway, so I connect the new battery, and the situation is exactly the same, no dash lights, no central locking, no cigarette lighter, I can not find any electrical system that works-- even ones that do not require ignition to be on.

I see battery is charged perfectly with a multimeter. I see there is also power after the rear fuses (the ones in the box next to the battery), so it is not a simple terminal/connection issue and the big fuses in the back seem OK. I see the jump-start post under the hood also has power. That part is a bit more volatile on my cheap analog multimeter, but possibly because the posts have some surface corrosion. So I conclude electricity reaches all the way to the front of the car.

After taking useless detours by researching immobilizer, key etc, I am at my wits’ end. Could there be another main fuse that went bad and I might be missing (Other than the ones right after the battery)? How would you go about diagnosing something like this further? I

All help is much welcome. The car is in the office garage, and it will be a real hassle to get it towed only to find I was missing something very obvious.

Kimo · 05-01-2015, 10:11 AM

That's a tough one - sorry you're going through this.
I do not have an answer off the top of my head, and do hope that others will jump in, but if it were me (and at the risk of sending you on another wild goose chase) I'd start researching Z4 fusible links. At least it's a place to start pending better advice.

calcerr · 05-01-2015, 10:50 AM

Thank you, Kimo, yes, this looks like it will not be a quick one. I ordered a service manual to be able to check where the fusible links are.

Kimo · 05-01-2015, 12:22 PM

Fusible links SHOULD be in relatively close proximity to the battery itself, but in a car as small as the Z4, "close" is debatable. And the fact that you have current downstream from the aft fuse box, and also at the forward remote jumping post, is a bit counterintuitive.

StickMon · 05-01-2015, 12:47 PM

This might help.

terminal 30.pdf

Kimo · 05-01-2015, 01:31 PM

Quote:

Originally Posted by StickMon

This might help.

Attachment 1202242

Yep. My money's on the AMG-250A bolt-in megafuse in the trunk - Stick's diagram seems consistent with OP's empirical findings.

calcerr - could there have been some sort of electrical 'trauma' / current overload to your car?

Look here for pics:

http://www.ebay.co.uk/itm/BMW-Z4-E85...p2047675.l2557

http://www.ebay.com/itm/Battery-back...-/151449039066

http://www.ebay.co.uk/itm/BMW-Z4-E85...-/191189059526

http://www.ebay.com/itm/BMW-E46-325-...-/181610350315

calcerr · 05-01-2015, 05:00 PM

Thank you so much to both of you, super helpful!

It does look like the 250 amp could be the culprit, and the jumper posts would still have current. Why would such a big fuse would go out, I don't know. There are no 'traumas' I can think of, and the car was parked. Anyway, at least I have a roadmap now! Will keep you posted, and have a good weekend!

tlrominger · 05-04-2015, 06:48 AM

If the fuse is not the issue I would start looking at the ignition switch.

Reborn_ · 05-04-2015, 10:29 AM

Quote:

Originally Posted by tlrominger

If the fuse is not the issue I would start looking at the ignition switch.

Ignition switch wouldn't impact electrical items that don't require ignition, like dome lights. This is definitely an electrical problem.

calcerr · 05-13-2015, 04:57 PM

I did not sort this problem yet, as I am travelling, but the main 230 amp fuse looks good. So I am going back to the battery itself. Hopefully that is it, and I get back my M alive soon, gof ro a drive, and post some pictures as well. Thanks for everyone for the support.

trevor · 05-19-2015, 04:41 PM

Rare findings will indicate after long periods, bugs can make their homes inside the cars and cut through the wiring as well.

05-01-2015, 09:13 AM	#1
calcerr Registered 1 Rep 4 Posts Drives: 2007 Z4M Join Date: Apr 2015 Location: United States iTrader: (0)	Z4M no start no dash lights, advice requested Hi everyone, Newbie in the forum here. I bought few months ago a 2007 Z4M coupe, which has developed a simple-looking, but (for me) vexing issue. The car is parked for longish periods, as I don’t drive daily. So I come back to it after several weeks, and find that there is zero battery power, no dash lights and no systems at all. I thought the battery was dead, and once I saw it was lead acid, I hurried to change it with an AGM H6. I did not test the old battery, which was a bit stupid. Anyway, so I connect the new battery, and the situation is exactly the same, no dash lights, no central locking, no cigarette lighter, I can not find any electrical system that works-- even ones that do not require ignition to be on. I see battery is charged perfectly with a multimeter. I see there is also power after the rear fuses (the ones in the box next to the battery), so it is not a simple terminal/connection issue and the big fuses in the back seem OK. I see the jump-start post under the hood also has power. That part is a bit more volatile on my cheap analog multimeter, but possibly because the posts have some surface corrosion. So I conclude electricity reaches all the way to the front of the car. After taking useless detours by researching immobilizer, key etc, I am at my wits’ end. Could there be another main fuse that went bad and I might be missing (Other than the ones right after the battery)? How would you go about diagnosing something like this further? I All help is much welcome. The car is in the office garage, and it will be a real hassle to get it towed only to find I was missing something very obvious.
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05-01-2015, 10:11 AM	#2
Kimo Lieutenant 40 Rep 525 Posts Drives: E31 E90 F25 MCS Join Date: Jun 2005 Location: Maryland iTrader: (0)	That's a tough one - sorry you're going through this. I do not have an answer off the top of my head, and do hope that others will jump in, but if it were me (and at the risk of sending you on another wild goose chase) I'd start researching Z4 fusible links. At least it's a place to start pending better advice. __________________
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05-01-2015, 10:50 AM	#3
calcerr Registered 1 Rep 4 Posts Drives: 2007 Z4M Join Date: Apr 2015 Location: United States iTrader: (0)	Thank you, Kimo, yes, this looks like it will not be a quick one. I ordered a service manual to be able to check where the fusible links are.
	Appreciate 0 Quote

05-01-2015, 12:22 PM	#4
Kimo Lieutenant 40 Rep 525 Posts Drives: E31 E90 F25 MCS Join Date: Jun 2005 Location: Maryland iTrader: (0)	Fusible links SHOULD be in relatively close proximity to the battery itself, but in a car as small as the Z4, "close" is debatable. And the fact that you have current downstream from the aft fuse box, and also at the forward remote jumping post, is a bit counterintuitive. __________________
	Appreciate 0 Quote

05-01-2015, 12:47 PM	#5
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	This might help. terminal 30.pdf __________________ Warning: May contain traces of nuts.
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05-01-2015, 05:00 PM	#7
calcerr Registered 1 Rep 4 Posts Drives: 2007 Z4M Join Date: Apr 2015 Location: United States iTrader: (0)	Thank you so much to both of you, super helpful! It does look like the 250 amp could be the culprit, and the jumper posts would still have current. Why would such a big fuse would go out, I don't know. There are no 'traumas' I can think of, and the car was parked. Anyway, at least I have a roadmap now! Will keep you posted, and have a good weekend!
	Appreciate 0 Quote

05-04-2015, 06:48 AM	#8
tlrominger New Member 0 Rep 26 Posts Drives: 2005 Z4 Sport Join Date: Jan 2011 Location: Dallas iTrader: (0)	If the fuse is not the issue I would start looking at the ignition switch.
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05-13-2015, 04:57 PM	#10
calcerr Registered 1 Rep 4 Posts Drives: 2007 Z4M Join Date: Apr 2015 Location: United States iTrader: (0)	I did not sort this problem yet, as I am travelling, but the main 230 amp fuse looks good. So I am going back to the battery itself. Hopefully that is it, and I get back my M alive soon, gof ro a drive, and post some pictures as well. Thanks for everyone for the support.
	Appreciate 0 Quote

05-19-2015, 04:41 PM	#11
trevor New Member 2 Rep 28 Posts Drives: 2005 BMW Z4 and 2001 BMW 515i Join Date: May 2015 Location: Washington, D.C. iTrader: (0)	Rare findings will indicate after long periods, bugs can make their homes inside the cars and cut through the wiring as well.
	Appreciate 0 Quote

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