Battery polarity crossed

Hello,

Well, I think I made a big boo boo. The battery died (rather suddenly, I might add) on my '03 tdi Jetta. I have an Optima that sort of fit, which I tried installing as a temporary fix until I could get the correct battery. However, I missed that the poles were on opposite ends of the Optima. I accidentally touched the cables to them and got a pretty substantial spark before realizing that I was trying to hook up to the wrong poles. Since the battery didn't physically fit in the space anyway, I took it out and just got the right battery. When I finished installing it, the car started and most functions worked, but the low beam on the left headlight was suddenly out. A few miles of driving later, the right low beam was also out. Then I noticed that the radio was completely dead - no lights, no code, no radio noises ...nothing.

I checked the fuse panel and saw that the 25 amp fuse, number 42 (which I take is the radio fuse altho that isn't indicated on the diagram or anywhere else I can see), was blown. All the others that went to non-functioning or unknown (they have that mysterious open book symbol in the fuse diagram) circuits were good. I don't get any problem lights on the dash (check engine, etc).

I bought a replacement headlight bulb and installed it in the right side, after finding that the low beam filament was burned out. I haven't checked it yet, but I suspect that I blew the left side low beam filament too.

Has anyone had a similar experience? Any comments (aside from the obvious about what an idiot I am), suggestions or explanations as to why they'd make the car so sensitive to this kind of error? Any suggestions about fixing the radio? Did I kill it? It seems the charging system still works and after reading the post about another guy who made the same mistake and lost his alternator in the process, I guess I'm lucky. But really, this experience sort of makes me wish they still made 'simple' cars, like they used to. Anyway, thanks for any help.

tdiphile said:

Hello,

Well, I think I made a big boo boo. The battery died (rather suddenly, I might add) on my '03 tdi Jetta. I have an Optima that sort of fit, which I tried installing as a temporary fix until I could get the correct battery. However, I missed that the poles were on opposite ends of the Optima. I accidentally touched the cables to them and got a pretty substantial spark before realizing that I was trying to hook up to the wrong poles. Since the battery didn't physically fit in the space anyway, I took it out and just got the right battery. When I finished installing it, the car started and most functions worked, but the low beam on the left headlight was suddenly out. A few miles of driving later, the right low beam was also out. Then I noticed that the radio was completely dead - no lights, no code, no radio noises ...nothing.

I checked the fuse panel and saw that the 25 amp fuse, number 42 (which I take is the radio fuse altho that isn't indicated on the diagram or anywhere else I can see), was blown. All the others that went to non-functioning or unknown (they have that mysterious open book symbol in the fuse diagram) circuits were good. I don't get any problem lights on the dash (check engine, etc).

I bought a replacement headlight bulb and installed it in the right side, after finding that the low beam filament was burned out. I haven't checked it yet, but I suspect that I blew the left side low beam filament too.

Has anyone had a similar experience? Any comments (aside from the obvious about what an idiot I am), suggestions or explanations as to why they'd make the car so sensitive to this kind of error? Any suggestions about fixing the radio? Did I kill it? It seems the charging system still works and after reading the post about another guy who made the same mistake and lost his alternator in the process, I guess I'm lucky. But really, this experience sort of makes me wish they still made 'simple' cars, like they used to. Anyway, thanks for any help.

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There may be a fuse on the back of your radio (will need to take it out) that you can replace, depending on the year of your car.

Thanks Eric, I understand that the radio requires some kind of special, secret key (or is it a handshake?) to remove. Any suggestions?

Yes fuse 42 is for the radio and as mentioned there's another 10 A one on the back it.

Depends on what year you have. On a '00 passat, I was able to use the metal part from hanging file folders as keys to pull the radio out.

The profile says 2003 Jetta. Most likely a double DIN headunit that requires the four keys in the corners to remove. There are some old threads with guides on how to make your own.

Thanks for the help. Yes, it's an '03. Anything special I have to know about replacing that 10A fuse on the back of the radio? I'll go look for those threads on making up a set of keys now. Thanks again... ;-)

Er, uh, any suggestions on how to find one of those threads on making up a set of radio removal keys? I've been searching for a half hour now and can't find anything. Thanks again...

tdiphile said:

Er, uh, any suggestions on how to find one of those threads on making up a set of radio removal keys? I've been searching for a half hour now and can't find anything. Thanks again...

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I had zero luck making radio keys. It just would not work. I ended up buying a set of four keys (they are under 10 bucks). I think I also remember seeing them at Walmart as well. If you pm me your mailing address I will lend you my keys. Just mail them back when your done.

Btw, welcome to the tdiclub

I had 2 radio keys and and tried to make 2 more. First using a credit card, and they using a CD. Both proved too flimsy to actually catch the mechanism.

I ended up just using the two keys. Popped the left side, and angled the radio slightly, then popped the right side and pulled the radio out.

And yes, you will probably need the code for the radio. Look through your manual. That's where I found mine.

I don't know why VW makes it so difficult. I mean, do people still steal stock radios these days? :S

You can get the keys for cheap on ebay. Get 4 if you can.

I blew the fuse in my radio boosting the battery.

It didn't need the code when the fuse was replaced.

I tried making keys from a credit card and it didn't work for me either.

Here's the instruction I used to make 'keys' from a hanging file folder:
http://forums.tdiclub.com/showthread.php?t=156035
You'll need 4, not 2.

Making the radio removal tools. (assuming you have some metal shears)

First go to Ebay and do a search .......... find the tools. Look at the pictures so you have an idea of what they look like.

Next, purchase a "hack saw" blade. Cut the blade in the middle (hence two tools). (The ends with the hole will be the "handles.")

Next, using the metal shears, cut off the teeth of the hack saw blade. You need to do some measuring before you cut. Cutting off the teeth should leave the blade about 9mm wide. It is important that the blade is not smaller than 9mm wide (8.5mm might work). A snug fit is important for proper usage.

Now, cut a 45 degree angle on the end of each blade (opposite the hole on each end of the blade).

Now, the device will work to release the holder of the radio, but it will not pull it out. There needs to be a notch cut in the blade about half way down the 45 degree cut. The notch will serve to "hook" the radio release and holding device.

You need to look at the Ebay photo...... it helps.

Now, inserting the two tools is important. The 45 degree angles must be pointed toward the center of the radio in the two slots on either side of the radio. When you push the tools "in" you should feel resistance and finally hear/feel a click. It is ready to pull straight out. The fuse is on the back left.

I made mine the first try ........... they have been used numerous times and work perfect.

Give it a try!............... good luck!

I made keys out of sheet Al, cut with tin snips- worked just fine.

I've successfully used a cut up old credit card on several occasions on single DIN radio. Never tried it on a D-DIN.

eric_x said:

Depends on what year you have. On a '00 passat, I was able to use the metal part from hanging file folders as keys to pull the radio out.

Click to expand...

I made a set of tools like that and cut the **** out of one of digits. The radio came out, but I promtly shelled out the 8 bones for a set of tools from shEbay.

I haven't finished reading the thread so please forgive the echo if it's been mentioned. You can usually talk a stereo installer to loosen it for you. Just make sure it's working b4 you push it back in all the way.

Radio removal tools

Like I said, I've successfully used my speciality made radio removal tools numerous times.

I keep them in my box of speciality tools.

Thanks to all of you for the terrific information. Last night I found a thread on the Vortex site that had great photos and an explanation about removing the radio.

I picked up another headlight bulb earlier today. Then, before catching up on this thread, I replaced the (other) headlight bulb, which was also blown from crossing the battery poles. I then tried removing the radio with the cut up credit card tool trick but found, as many of you have, that it doesn't work very well. Three out of four of the 'keys' opened their respective locks, but the one that didn't had to be replaced with a flat slip of metal. The short story is that the 10A fuse in the back was, in fact, blown. Replacing it fixed the dead radio issue. Nothing further was required.

The long story is that, after removing the radio with some difficulty, using cut up the credit card, I made up a set of 4 keys, cut from a scrap bit of sheet metal. Since the radio was out of the car at that point, I was able to make them the exact shape and size where they would work easily, which I was able to test by repeatedly inserting and removing them from the slots and watching the spring clips that retain the radio move in and out.

To what's already been written, I would add that if you slightly wiggle whatever keys you have from side to side as you slowly insert them, you'll find that they will do the trick with less stress on both the locks and you, and you'll get the radio to come out pretty easily.

As an aside, the radio in this car is not the original Monsoon. I bought the car new with a Monsoon but didn't use the cassette player for the first 2 1/2 years. The first time I did, it wouldn't release the cassette and I had to take it to the dealer to, ultimately, have them pull the radio out and replace it with another. That turned out to be a nightmare as I had to return the car to the dealer 5 times before they finally did the job right without screwing something else up in the process. Only when I removed the radio today to fix the current problem did I find that the radio they gave me under warranty was a refurbished unit. What a bunch of bums. Btw, that's Santa Monica VW, in case anyone cares. After having had so much trouble with them originally with the car, I never returned for any other service. Make that double definitely won't go back to them now - for anything.

Anyway, to end on a good note, thanks again for all the help. I really appreciate the great advice and assistance, as well as the offer to borrow keys. You guys are life savers.

Wanna explain how reverse polarity blows a lamp filament?

DPM said:

Wanna explain how reverse polarity blows a lamp filament?

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it doesn,t............ but how does someone cross the battery terminals that one i can't understand how that happens, that is NOT the fault of the car or design, just owner foolishness

chrisfiat said:

{snip} , just owner foolishness

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I watched someone do this on a '99 Mercury Cougar. Car wouldn't start after the battery mystery was solved. It blew the ECU that runs the car... hmm, expensive mistake. Consider yourself lucky. Now try not to add petroleum products to the brake master cylinder!