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Discussion Starter #1 (Edited)
Here's the problem, after third replacement in two weeks (if the picture is not here, go to the bottom of this post0 -



The running thread is here, but below is the breakdown of the pertinent facts to date, bad title to garner views and help from others
http://newbeetle.org/forums/2-0-liter-gas/52306-wiring-diagram-engine-grounds.html

Here's the vehicle, although irrelevant -
2002, 2.0L

Here's the history -

Compressor and Condensor replaced, no fuse issues prior to R&R, fans were operating properly before R&R, but are no longer functioning, don't think the fans not running is the direct cause, but possible damage to the wiring causing a short, as the problem didn't occur, but occured right after the a/c work. Would think if it were a wiring issue with the fans, Fusible Link Pos S164 or Fuse Pos S180 would show a problem. Update, fans do run when car is running, OPer indicates they will not turn on with a/c speed switch; verifying that when in the #4 position. States they DID turn on before the work was done with the engine not running (huh?).

The battery box has been changed, and all the fusible links replaced with new, three times in two weeks.

No active CEL or MIL, OBD has not been read for stored codes. VAG-COM not readily available.

Car is running, no starting or running issues.

No tests have been preformed as of this moment. OPer has a multimeter and novice experience. Trying to get a direction. I'm thinking a faulty voltage regulator allowing too much current from the alternator. Or possibly a dirty connection issue with the battery, causing the battery feedback not to block the output of the alternator. Also, not sure where to address the fan issue first, not knowing if it is the cause or the result.

Any thoughts, similar experience and resolve or diagnostic suggestions?

All learned help appreciated.

M.
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I have had to replace the fuse box on mine; the research I did seemed to indicate that people had come to the conclusion that resistance or increased draw was causing contacts at the box to heat up. These seem to break down into possible components causing the draw/heat at the box:

1. cooling/ac fans failing internally (internal resistors)
2. resistance in leads to alternator
3. alternator failure/regulator stuck causing overcharging
4. a/c compressor

I suppose any component; could caused extra draw and heat up the contacts at the fuse box; the question becomes which one?

Here is a thread that has good info and expounds on many possible reasons/solutions: Melted battery fuse box leads to no A/C? - TDIClub Forums
 

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Discussion Starter #3
I have had to replace the fuse box on mine; the research I did seemed to indicate that people had come to the conclusion that resistance or increased draw was causing contacts at the box to heat up. These seem to break down into possible components causing the draw/heat at the box:

1. cooling/ac fans failing internally (internal resistors)
2. resistance in leads to alternator
3. alternator failure/regulator stuck causing overcharging
4. a/c compressor

I suppose any component; could caused extra draw and heat up the contacts at the fuse box; the question becomes which one?

Here is a thread that has good info and expounds on many possible reasons/solutions: Melted battery fuse box leads to no A/C? - TDIClub Forums
Thanks billymade, have also found out that when the compressor and condensor were replaced, the OPer had been driving the car with the a/c down for a year or more. So... maybe the additional load of the new compressor triggered this, but what would change since it had originally failed?

M.
 

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I wonder if the new compressor is defective and are the fans ok (the fans go on when the a/c is active... another possibility); causing the increased draw? We have had faulty compressors in our shop; until testing is started... we are speculating at this point. A step by step process of elimination; need to be started, I'm not a auto electric expert but testing would start eliminating the variables. The tdiclub thread has allot of good info...
 

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Discussion Starter #5
I wonder if the new compressor is defective; causing the increased draw? We have had faulty compressors in our shop; until testing is started... we are speculating at this point. A step by step process of elimination; need to be started, I'm not a auto electric expert but testing would start eliminating the variables. The tdiclub thread has allot of good info...
Your right, and thanks for that link, going to have a good read of it when I get a little tme, just real busy right now. Haven't found out yet, why the OPer didn't take his car back to the shop that did the a/c work, with a "What's up with this?"

Funny, I read about Orgers changing these all the time assuming it is just a bad design and never mentioning the cause, as if it won't happen again. Something has to cause the failure, and unless fixed it's just going to recur. Three times in two weeks in this case. (lol)

M.
 

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I have been guilty of the same thing but throwing parts at a problem... doesn't always fix it! In this case; a symptom of a greater problem; heat, melting contacts; what is causing the heat?
 

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Thanks for the response I am the owner of the car in this discussion and I guess we all had to learn from somewhere....I did take it back to mechanic that installed A/C compressor, he told me that the alternator wire was not connected good in fuse block, tighten wire and I pickup car back up, ran good for a few days then melted second fuse block and then third this past Saturday. Any thanks to all for help advice....maybe I can figure it out before my car burns up!
 

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That black cable that is melting comes directly from the output post of the generator. It is a part of the generator wiring harness, but nothing else is connected to it. It is there to charge the battery and compleate the circit to the starter, coil pack, etc, to keep the engine running. That being said, that cable is failing or the voltage regulator is not working right, or the altinator is going bad. Tthe cable has continuity but, not enough, you can do a drop voltage test. You can test the regulator and altinator. IF the cable is bad you don't have to replace the harness, just make a new cable to go to the altinator and fuse block. Parts are about 20 bucks it beats 300 for the whole harness. I have been there and done this myself. The other fuse links apear to be fine, and that is why I suspect the problem is the altinator, voltage regulator or the cable itself. I'll bet it is the cable. This cable is known for going bad.
 

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Discussion Starter #9 (Edited)
Old related thread, no resolve
http://newbeetle.org/forums/2-0-liter-gas/18641-fusible-links-fried-again.html

@Stlbug
You had a similar issue
http://newbeetle.org/forums/2-0-liter-gas/50652-link-fuse-failure-engine-bay-fuse-box.html
What was the outcome as to cause, simply a loose connection, or am I gathering from your post above that you replaced the cable? What gauge did you use? The Bentley shows it as a 16mm² , between an AWG 5 and 6, I'm going to suggest the Oper use a 4 as I think a 5 might be hard to find if not impossible, and besides the 4 is only .028" larger in diameter. He needs to find a local shop that can do this, or order one and rig something temporary in the meantime.
Go here - http://shop.genuinedealz.com/Marine%20Grade%20Wire/Marine%20Battery%20Cable/?gclid=CJDKzfW4masCFcEZ2godID4zig
then go here and add - http://shop.genuinedealz.com/Items/custlabstore?&caSKU=custlabstore&caTitle=Custom Cable Assembly - Labor Charge
then go here and add - http://shop.genuinedealz.com/Marine Electrical Supply/Tinned Copper Cable Lugs/4 AWG Tinned Lug/ or this - http://shop.genuinedealz.com/Marine Electrical Supply/Heavy Wall Coppper Lugs/4 AWG Heavy Wall Lug/
then go here and add - http://shop.genuinedealz.com/Items/gim-tbca40-r?&caSKU=gim-tbca40-r&caTitle=4/0 AWG Starter/Alternator Boot - Red

Off the subject, but did you see the post about moving the battery to the trunk using existing speaker amp cabling? Can you imagine those issues? I had to rewire a factory battery run on a previous Vette, that wouldn't carry enough cranking amps to start the engine, and we did it with welding cable (2 AWG) and it was a lot more flexible because of the rubber insulation and more finely stranded wire.

M.
 

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Discussion Starter #10 (Edited)
I suppose any component; could caused extra draw and heat up the contacts at the fuse box; the question becomes which one?
I'm leaning away from that, and here is why. I just had to think this out, been away from automotive electics for a long time, and all the rhetoric was overloading my thought processes. Look at the wiring diagram, the battery is on one side of the fuse block, everything else is on the other, each isolated by another fuse from both the battery and the alternator, and overload from any one of those would have caused the respective fuse to blow, not the one that is melting. And think about the direction of the current flow as you look at the fuse block in the wiring diagram. Far left, inbound, all others, outbound.

Here is a thread that has good info and expounds on many possible reasons/solutions: Melted battery fuse box leads to no A/C? - TDIClub Forums
Went and had a read over on the TDI thread. The two posts most noteworthy follow, both experiences as a result of the alternator lead/connection. I'm leaning to replace this, until I get some test results from the subject vehicle. Actually hoping it will be confirmed by the voltage drop testing between the alternator and the fuse block.
 

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Yes I did have to replace the cable,it was guilty as charged!!! The altinator was fine it was the delivery tube,(cable) was bad. VW wanted a whole lot of money for the harness, 2 or 3 hundred dollors plus about 4hr. of labor, all that for one bad wire. That picture was just a little too ugly for me. Using welding cable would be nice, but it has to connect to that tiny little fuse block. So I used 4ga. battery cable with good stranded copper, not like the cheap crap vw used. The hard part was finding a shop with a crimper for the copper connection ends and I did have to do some adjustments to the copper connector to fit it into the fuse block. I dissconnected the old cable and taped of the ends with some high heat ruberized electrical tape. Then I routed the new cable to the fuse block staying away from the realy hot parts of the engine and added some heat insulator tubing over the cable and anchord it in a few spots with some zip ties. Works perfect and to my surprise it cleared up the intermintant electrical problems my car was having at the time. Corvettes are hard to work on esp the electrics, I have owned 3 of them in the past. One was a 63 split window, it was a piece of crap, none of the numbers matched. It was to be a project car, I gave up on it ,it was too hard for me. Wish I had it back, I see some of them go for 6.figures now, but that was 30 years ago.
 

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Discussion Starter #12
Yes I did have to replace the cable,it was guilty as charged!!! The altinator was fine it was the delivery tube,(cable) was bad. VW wanted a whole lot of money for the harness, 2 or 3 hundred dollors plus about 4hr. of labor, all that for one bad wire. That picture was just a little too ugly for me. Using welding cable would be nice, but it has to connect to that tiny little fuse block. So I used 4ga. battery cable with good stranded copper, not like the cheap crap vw used. The hard part was finding a shop with a crimper for the copper connection ends and I did have to do some adjustments to the copper connector to fit it into the fuse block. I dissconnected the old cable and taped of the ends with some high heat ruberized electrical tape. Then I routed the new cable to the fuse block staying away from the realy hot parts of the engine and added some heat insulator tubing over the cable and anchord it in a few spots with some zip ties. Works perfect and to my surprise it cleared up the intermintant electrical problems my car was having at the time. Corvettes are hard to work on esp the electrics, I have owned 3 of them in the past. One was a 63 split window, it was a piece of crap, none of the numbers matched. It was to be a project car, I gave up on it ,it was too hard for me. Wish I had it back, I see some of them go for 6.figures now, but that was 30 years ago.
No for this, welding cable (#2 AWG) is way overkill. What's there is just smaller than #5 and I think too thin, I think that's part of the problem with most of these melt downs. Yeah, finding someone to make up the cable and crimp or soldier on the connectors is going to be the bitch, the reason I put up the online resource. Bet they will get it out same day and overnight it. Beats the hell out of running around all over hell's half acre. And I figured the fuse block connector would require modification.

Off topic, I remember going with Dad when he traded in his Austin Healey 3000 (real wire hub spinners) at Chevy. He was looking at a new '62 Ragtop (the classic red with white insets) and I was in love!!! They had just got a '63 Split Window in that he also looked at. To my great disappoitment we left that day in a '62 Corvair Monza Spider (air-cooled turbo) 2 dr. TG that got replaced the next year with a '63 Pontiac GP, 389 cid, 3 spd Hydramatic (race track A/T), Posi-trac, which was to become my first car.

Have a good day, buddy.
 

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Discussion Starter #13
Help!

Performing voltage drop test and getting readings of 0.7 v., can anyone confirm that this is correct for this circuit in the NB. The Toyota manual I have says 0.2 v. but if memory serves, this would have to do with wire size.

Help!
 

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You are correct sir, it is the wire size, length, and amperage output., plugged into a fancy formula that gives you the voltage drop for a particular pieceof wire. Google voltage drop and there is a calculator there to plug in your numbers. I don't know if this is what you need. I had VWdealership test mine when I picked up the new fuse block. They just told me my cable is no good and the altinator harness must be replaced. I said thank you ,I will take care of it myself.
 

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Discussion Starter #15
You are correct sir, it is the wire size, length, and amperage output., plugged into a fancy formula that gives you the voltage drop for a particular pieceof wire. Google voltage drop and there is a calculator there to plug in your numbers. I don't know if this is what you need. I had VWdealership test mine when I picked up the new fuse block. They just told me my cable is no good and the altinator harness must be replaced. I said thank you ,I will take care of it myself.
Thouhgt so, but it's been a long, long, time.

I had the OPer test from both sides of the fuse block, stud mount to stud mount on each of the components (alt & bat). Reading was the same on both sides. Fluctuating between 0.7v. and 0.8v., I'm assuming because of attempting to hold 2000 rpm at the same time. He had done this after my giving im the info on how drop load testing works, but before I explained the multiple tests needed to isolate the problem. He did stick the probe into the wire insulation just beyound the bare wire at the fuse block, and ran to the alt stud mount. Voltage drop dropped to 0.05v, indicating a bad/corroded, wire/connector/connection, at the mounting. Obviously a problem on the other side of the fuse block also. Waiting for the results of the rest of the voltage drop tests I ask him to perform, including the ground side segments. In following my suggestion, he called around and found a guy who builds custom cables, was told n/p about $20 ea., bring his old ones for connector matching. Recommended he use #4, a little heavier than one size larger than the 16mm² that VW uses, and I'm sure way better quality wire.

I'll update as more is learned.

M.
 

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Discussion Starter #16
Still looking for comments, thoughts, or experiences...

Appreciated!

M.
 

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Issue Corrected

Thanks to all for the help and advice, the beetle is repaired....The volt regulator was toast and would not show any effect until high RPM's. So after doing all the testing @ 2000 RPM all was well. I went out on a $240 limb and replaced the alternator and cable, the car has never ran better. I am thankful it is back up and running....Again thanks to all! :):)
 

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Issue Corrected

Simply put the voltage regulator failed causing the system to over charge....Good luck to all in the future, also thanks again I learned many new things in dealing with this repair.
 

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Discussion Starter #19
Excellent!

Thanks to all for the help and advice, the beetle is repaired....The volt regulator was toast and would not show any effect until high RPM's. So after doing all the testing @ 2000 RPM all was well. I went out on a $240 limb and replaced the alternator and cable, the car has never ran better. I am thankful it is back up and running....Again thanks to all! :):)
Excellent! Glad you have gotten the issue(s) resolved. Alternator problem determined with a load test? Was the voltage regulator allowing it to over charge causing the melt down at the fuse block? Important info if you know!

M.
 
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