Mysterious electrical problems..I think

[HDhandyman]

So, first off, sorry to start so many new threads. Today was first trip in town during rain. So naturally had to turn on defrost @ idle (stoplight) for like 30 secs. Light turned green, car starts to go and ---suddenly---car is dying--seems like not getting fuel--no power--then stand still. Pulled over--in rain--checked O2--fine, turned off car, scratched head, restarted car (of course defrost is now off, haven't made connection yet), car is fine--but wobbley?. Finally got car stop light, turned on defrost again and same thing--car is loosing power/ fuel--dying. Make mental connection, turned off defrost, car is fine--gets power back. Pulled over @ destination, check engine light=1222

I'm a nube, and I'm at a loss--Help Please.

Thanks,

Stephen

[uscharalph]

So, first off, sorry to start so many new threads. Today was first trip in town during rain. So naturally had to turn on defrost @ idle (stoplight) for like 30 secs. Light turned green, car starts to go and ---suddenly---car is dying--seems like not getting fuel--no power--then stand still. Pulled over--in rain--checked O2--fine, turned off car, scratched head, restarted car (of course defrost is now off, haven't made connection yet), car is fine--but wobbley?. Finally got car stop light, turned on defrost again and same thing--car is loosing power/ fuel--dying. Make mental connection, turned off defrost, car is fine--gets power back. Pulled over @ destination, check engine light=1222

I'm a nube, and I'm at a loss--Help Please.

Thanks,

Stephen
Are you talking about the rear window defrost?

[HDhandyman]

To be perfectly honest, I'm not sure--I just Pressed the button on the dash panel that sits above A.C. AND recycle.

[uscharalph]

To be perfectly honest, I'm not sure--I just Pressed the button on the dash panel that sits above A.C. AND recycle.
That's the rear window defrost (Defog).

[HDhandyman]

OK so what does that mean?--where is normal defrost?--And what is the problem then?

[uscharalph]

OK so what does that mean?--where is normal defrost?--And what is the problem then?
I know what it is, but I don't know what the problem could be, sorry. I'm sure someone around here can help though.

[HDhandyman]

what do you mean--"Know what it is" ??

[uscharalph]

what do you mean--"Know what it is" ??
It means exactly that, I know what the button you hit is. It is the rear window defroster.

[HDhandyman]

So, I guess this is really a mystery huh?--Nobody here knows anything about a rear defrog --power drain connection?

[uscharalph]

So, I guess this is really a mystery huh?--Nobody here knows anything about a rear defrog --power drain connection?
Some times you just gotta give people a little time. Or maybe it is a mystery. Just don't use the rear defroster. Or you could take it to the dealer. LOL!!

[mattyb]

you're a pushy little bugger aren't you. Give people time to respond. not every thread is answered in 2 minutes. people have jobs and other things to do, you will find that an answer will most likely be forthcoming soon. I am sorry i cant help you on this one but u need to give folks time to look and help. Please take this a gentle advice as u seem to be making a habit of expecting something that we are not and I know others might not say so but it gets a bit challenging to see the kind of respones that have been posted so far by you. Chill

[Javier]

If so, un-lock it and test voltage (test 9) at different stages of your observations. You may have a weak battery combined/originated in a poor alternator, or loose connections over the electrical system feeders causing voltage to drop under significant loads.

OBC Link (http://home.iae.nl/users/bts/obc.htm)

Javier

[shogun]

Please be a bit more polite on this board.
First make your homework and read the owners manual. There you will see all the instruments and push buttons.
If you even do not know for sure which button you pushed and what that means, how can we help you?

If you want help, then please ask politely and tell us in detail what has happened, what you have done to solve the problem so far, etc etc.

[HDhandyman]

Well--too bad, I was just hoping this was another one of those obvious things that everybody has already been through and knows how to fix. I'm still searching for the problem--seems to be some sort of electrical crosswover because battery is brand new and this happens under any load--with a little engine rev. I'll keep you guys posted this weekend while I perform iPod mod and investigate. Sorry to be so pushy.

Your newest resident grand-stander,

Stephen

[shogun]

We try to help.
So please do the test which Javier suggested.
He is probably the one with the best electric knowledge here and he can guide you thru.
Just for a starter , Javier has once written this and that might help you too to check in addition after you have checked first the simple things like the battery voltage and the charging voltage.


If you are a beginner in electric issues, this walks you through it, hopefully:

I'll try to make it simple, ...

The meter should have an A scale (Ampere) for reading current. Preferably, a High amp one (10A for example). In some of them, this high amp scale requires the red plug of the wire probes to be connected in a different hole. We do not know the magnitude of the current involved, so in order to preserve the meter, it is better to start reading in this high amp scale.

Disconnect the ground (negative) lead to the battery (electronic devices in the car will loose status when battery is unplugged, so you will need radio code for example), connect the positive (Red) meter probe to the negative thick wire to the battery, and connect the negative (Black) probe of the meter to the negative battery post. Be sure that the probes are inserted in the proper holes in the meter for the readings (Amp) you intend to take.

If you have a leak as you assumed before, you should have a significant reading in the meter (maybe/sometimes more than 50 milli amps, > 0.05 Amp). If the selected scale do not allow you to have a clear reading of the leaking current and you want to change down scales, do so. Remember that some meters require to select a new hole in the meter for the red probe in order to select a lower Amp (Current) scale.

Once your meter is properly set and you have a good steady reading of the leaking current, proceed to remove, one by one, the fuses on the fuse box. Keep an eye to the meter in order to identify which fuse removal is dropping down the current in the meter. The leaky circuit is feed by that fuse.

Investigate what devices are associated to that fuse, plug the fuse back, and start disconnecting all devices one by one until you get again a reading drop. That device would be the culprit.

Written by Javier, and slightly changed by me to fit such question in general.
Hope that helps.

If the unlocking of the OBC to test the voltage is too complicated for you, then do the following:

Find a digital multimeter and and test the voltage on the available pole plus on ground in the engine room.

The following are the detail figures I use for my own evaluation:
With key out of ignition switch, should see 12.4V or above. 12.0 V is getting low.
With key inserted and turned to position 2 (don't start car), should see 12.0V or more. 11.6V would be too low.
Crank car, catch the lowest voltage reading during that couple of seconds. Should see 10.0V or above. 9.5V would be marginal.
The above just consider the health of battery itself.
Car running at 1500 RPM or more, should see 13.7 to 14.3V, 13.6V or below means the charging system is weak.


Please let us know the results of your checking so that we can proceed in guiding you thru the process of fault finding.

[uscharalph]

If so, un-lock it and test voltage (test 9) at different stages of your observations. You may have a weak battery combined/originated in a poor alternator, or loose connections over the electrical system feeders causing voltage to drop under significant loads.

OBC Link (http://home.iae.nl/users/bts/obc.htm)

Javier
I knew if anyone was going to know something about this, it'd be Javier.

[HDhandyman]

Ok, so I checked the battery and alternator--both in perfect shape--what's next...the OBC, or does that no longer apply?

[Kalevera]

When I first read this thread, I thought the same thing that Javier wrote. Unless fuses are blowing (or other activity to indicate a short), it's almost guaranteed to be the battery.

What kind is it? How old is it/Does it have an existing warranty? I've seen batteries that will charge up and hold it, yet the second you put load on it, it'll be gone. So, unless it's a new/year old battery, I'd replace that and then go from there.

Best, whit

[HDhandyman]

Thanks Whit,

This battery was in car pre-purchase, but looks to be new--like year or so--it's an AutoCraft Titanium--part # 41-2. Does this help?--It checks out during test--but I'll get a new one if you think I should.

[Paul in NZ]

get the battery load tested,there are places that will do it for you.These cars are very voltage sensitive.Is it Autozone that will do this guys???

[Kalevera]

Yes, but I don't know if I trust them to accurately test the battery. At least when I was a denizen of the local AutoZone store (a year ago in NC), they managed to offend and annoy me (by selling me the wrong/non fitting parts) more often than not. If you know exactly what they're going to give you, it's an okay place. Otherwise, a respected garage should have a good battery tester...

hmm, unless the battery has a date stamp on it (and most of them do), I wouldn't be so quick to think that it's new -- don't forget, it's well protected under the seat.

One machiavellian way to test this is to go to autozone and pick up a 49-D. Install it and test the car. If the problem is still there, return the battery.

best, whit

[632 Regal]

alternator isnt kicking/regulator or bad/corroded grounds if the priors check out.

[Javier]

engine is running, alternator should provide enough power for the rear defogger.

A weak alternator with voltage regulator issues, will keep low voltage at the battery, and fail to provide proper power under load.

Again, I would check the voltage under load conditions, if OK at the + post in the engine compartment (OBC will tell), I would check the voltage at each and every fuse related to the DME and engine operation. It is still probable to have a high resistance connection on the wires coming from the battery/alternator to the power distribution centers, causing low voltage conditions under load (Rear defogger on) and interfering with the proper operation of the engine electronics. I wouldn't blame the defogger itself, as Lowell said, it is not burning fuses. Just my guess.

Javier

[HDhandyman]

hey guys,

I went to auto zone today to get replacement fog lamp--simple thing. Since I was there, and it's free, I asked them to check this stuff for me--which they did--so that's where my results came from. However, while I was there, the store clerks were unable to help some guy install basic tail light. I actually ended up going over to him with my tools and taking care of the job they couldn't figure out. So confidence level is low--with them. I'll take it to my euro tech. on monday for testing, but something noobish is telling me that this is not the problem. Just a hunch, but I don't wanna let you down by not following through with your suggestions. Jeff you could be on to something with the grounds.--I'll keep you guys posted.

P.S. this is seriously getting in the way of my iPod mod, which will be my first major contribution to this forum. I think that's pissing me off way more than power loss right now.

P.P.S--I've been hearing weird noises--one is a sort of intermitant whining and the other sounds like white noise (not stereo). Both audible inside the car, and both increase in volume with acceleration (gas). Is there a connection?
Stephen

[uscharalph]

hey guys,

I went to auto zone today to get replacement fog lamp--simple thing. Since I was there, and it's free, I asked them to check this stuff for me--which they did--so that's where my results came from. However, while I was there, the store clerks were unable to help some guy install basic tail light. I actually ended up going over to him with my tools and taking care of the job they couldn't figure out. So confidence level is low--with them. I'll take it to my euro mech. on monday for testing, but something noobish is telling me that this is not the problem. Just a hunch, but I don't wanna let you down by not following through with your suggestions. Jeff you could be on to something with the grounds.--I'll keep you guys posted.

P.S. this is seriously getting in the way of my iPod mod, which will be my first major contribution to this forum. I think that's pissing me off way more than power loss right now.

P.P.S--I've been hearing weird noises--one is a sort of intermitant whining and the other sounds like white noise (not stereo). Both audible inside the car, and both increase in volume with acceleration (gas). Is there a connection?
Stephen
The only thing I could add would be keep doing what you're doing first and get these things straightened out, then you can get your iPod in. We're pulling for you!

[Kalevera]

alternator isnt kicking/regulator or bad/corroded grounds if the priors check out.
Bad grounds! YES! Why didn't I think of that

Don't forget, the battery is nothing more than a gigantic resistor. Internal resistance is affected by plate conditions and the like. The digital devices in the car have heavy current spikes, meaning that turning on the defroster could've sapped enough juice from it to keep everything else running. A somewhat obtuse example: if the battery parasitically drains while the car is under way, the alternator isn't going to be able to attempt charging it and keep the DME happy. I've seen this happen before...not on a BMW, but still.

But check the ground straps. I've had the occasional case of dumbshits and forgotten to reconnect one, then wondered why the car wouldn't start ;)

best, whit