Nardosdad

My daughter jump started my 2002 LS 430 after leaving the parking lights on for a day. Unfortunately they crossed the jumper lines. The car has 198000 miles on it and has been trouble free for the 8 years I have owned it.

Car would not start. When I got in to town a couple days later, I checked all fuses and replaced 2 Fuel Injection fuses. I visually checked all fuses as follows. 3 fuseboxes under the hood. Both driver and passenger kick panel fuseboxes, 1 fusebox in the driver side trunk. I then turned the ignition key on and got no interior gauges except for a couple of lights.

Jump started the car and the engine fired up. When I disconnected the jumper cables it died again. I restarted and kept it running for 20 minutes trying to build a charge. Still died after disconnecting jumpers. I removed the battery and had it tested. It failed one of the tests, so I replaced it with a new battery. Installed the new battery and car starts, but still no interior gauges, no dvd multifunction display, no tail lights, no indicators. Will not shift out of park unless the manual override switch is used. I drove it home and the steering feels a little harder as well. When decelerating, just before coming to a stop there is a harsh downshift. I finally shifted to neutral when coming to a stop to prevent that.

Any guidance on what I should do next. I have been reading forums for 6 hours without finding a similar situation. I have cleaned the (New) battery terminals and checked the battery cables at the battery end. The car starts readily, but I believe that I am only running on the original charge of the battery, and that the charging system is not working either.

LionsGate

I suspect you've lost some of the factory installed smoke in either your engine ecu or alternator. If that's the case a replacement will be in order.

Seriously though, glad no one was hurt, I've heard of jumper cables catching afire almost instantly in such cases.

I'd say check the simple things first, there should be a main fuse - usually 80-120 amps...look for such and pull it and inspect, then reinsert if fuse seems good.

If you're not that lucky then it's time to have the alternator tested, beyond that I'd guess it's new ecu time.

I wish I could be of help but it's not an area I've had experience with thus far.

Gene01

You might try checking the system voltage (with a digital meter - $2.99 at Harbor Freight))
WIth the key off, you will measure the battery voltage, and it should be about 12.6 V.
If it is more, take out a patent because you are getting free energy.
If it is less, you have a battery that is either in poor shape or needs charging (or both).

With the engine runing (at idle is OK), you should see between about 13.2 and 13.8 V depending on the state of the battery charge.
If it is much higher (maybe 14.5 or more), the voltage regulator inside the alternator is shot, and it will destroy the battery it is trying to charge.
If it is less, the alternator is not charging the battery. You can expect perhaps 20 minutes of engine running time before the battery is exhausted.

Dajap

iTrader: (1)

Should be a 120 amp Alternator fuse under the hood. Check and see if it is blown. I blew that fuse today on my IS300 and lost my gauge cluster, all lights, windows. Replaced the fuse and a couple other that blew at the same time and the IS300 is back to tip top shape. The Alternator fuse cost me $21 at the lexus dealership.

Nardosdad

I had checked all fuses I could find, so finally I took the car to the dealer. They tell me there is a main fuse (not listed in the owners manual) that you need to remove the battery and the fuse box next to it to get to. They estimate they will have it done this morning, so hopefully that will be the end of the story.

Nardosdad

Thanks Gene01 for your post. The battery that they tried to jump start was damaged and I had already replaced it with a new battery. I had checked the voltage on the new battery with the car running and it was not being charged. I did manage to drive the car home, and then to the dealer.

honeygee2

In actuality when you cross jump the battery cables you are now putting 24 volts into the system...not a good thing. Volts do not normally trip or burn out fuses...amps do. Thats why fuses are rated in amps. If you get off with a simple battery replacement thank your lucky stars and go buy a lottery ticket instantly. I don't know if the alternators still have diodes in them but that might be the cause of no charging. Good luck and keep us posted.

Gene01

"24 volts into the system" -
This is actually not correct. The only way to get 24 V DC into the system is to hook up two 12V batteries (both reasonably good) in series. It would look something like this:
+ cable --- (+)Bat1(-) --- intermediate cable --- (+)Bat2(-) --- Ground cable.

When you connect juimper cables, you always connect the batteries in parallel - like this:
+ cable ---T--- (+)Bat1(-) ---T--- Ground cable
. L--- (+)Bat2(-) ---I where the L and I represent the jumper cables (I can't get the L and I to line up with the Ts)
This provides 12V to the system, but at the sum of the currents of the two batteries.
Of course, if the original battery (Bat1 in the diagrams) needs charging (probably true if you are jumping),
it will absorb current from Bat2 rather than providing it, so the sum to the system will be less than the current that Bat2 is supplying.

Now, if you hook up Bat2 with reversed polarity, it will provide -12V (with respect to ground) to the car's system.
SInce it is probably stronger than the car's battery (Bat1), it will drive the supply voltage negative (somewhere between -0 V and -12 V depending on the states of the two batteries).
In other words, the electrons will flow in the opposite direction than they should, assuming that the jumper battery is better than the car's battery.

In old cars (before the age of computers), this did not do anything particularly bad to the car, but it didn't provide as much current to the starter motor, and the car would likely not start.
However, in the age of (expensive) electronic gizmos, there are three things that can happen to the "black boxes" when powered with reverse polarity:
1. Nothing - if they are designed to withstand reverse polarity. In fact, some devices (not automotive ones as far as I know) will still function properly.
2. Will not work - They simply refuse to perform their designed function, but will not be damaged.
3. WIll be damaged - Not only do they not work, but will never work correctly again. This should not be the case in a well-designed electrical system, but it is certainly possible.
There is a fourth possibility. A diode (for example) can allow a large current to pass in the reverse direction, and be protected by a fuse. If the fuse is properly sized (for current as honeygee2 mentioned), it will blow before the diode. In this case, everything should return to normal when the fuse is replaced.
It is possible that the component that allowed the large reverse current could be damaged in a way that appears later in its life, but we all hope that that did not happen.

Good luck on your repair, and if you can find out the precise location of the "secret fuse" from the dealer, could you post it here?

Nardosdad

Here is an update on the final outcome of this issue. The dealer called and my car has been repaired. The culprit was a "Fusible Link" which is located under the Fuse Box under the hood next to the battery. It is apparently necessary to remove the battery and that fuse box to get to the fusible link. Parts were $21 and labor $235.

All charging, lights, instrument panel, seat and multifunction display are in good working order. Thanks for all your input. My family will never again use jumper cables without double checking polarity!!!

BMW7_LS430

I wish I had seen this before, sorry.
I had criss-crossed cables too, accidentally.
I bought $3 120 AMP fuse from Advance Auto (instead of $45 140 AMP fuse from Lexus stealership) and replaced it myself.
$235 labor is just ridiculous for the job.