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SERIOUS mystery wiring issue...


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20 replies to this topic

#1 HILLBILLYHARLOT

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Posted 02 December 2010 - 10:57 AM

It started with the fusible link for the starter blowing. So, I replaced it. Next time I tried to start it.... nothing again. So, I made one with an inline fuse. I started at 7.5, and everytime I tried to start it, it blew fuses up to a 30 amp... I noticed it was sitting at 16v at an idle, then when I accelerate, it went up to 18. Last night, I was trying to get it home, and in 40 miles drained a brand new battery. Alternator tested @ 14.5 at the local NAPA, four times this morning. I have a short somewhere obviously, I just don't know where to start. It used to have starting issues where I'd have to wiggle the neg & pos cables, but it hasn't had that since I cleaned the cables at the battery and put new terminal connectors on. I'm not a wiring magician, I don't know how to read a volt meter, but I can learn :) HELP!!!!

#2 Gloyale

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Posted 02 December 2010 - 11:07 AM

Unwrap the large white wire coming off the Alternator. foolow it back to where it goes to the fusible link box. Look for any signs that it's gotten hot or melted.

If it's damaged, replace that wire. Just needs to be a heavy gauge wire from the alt to the Fusible link block.

If that wire looks good, then I would suggest that the alt is bad......bad diodes.

Are you getting any warning lights on while drivng? (Charge, Brake, Stop, etc.)

#3 skishop69

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Posted 02 December 2010 - 11:14 AM

I'd have to look at my wiring for sure, but it sounds like either the charge wire from the alt has rubbed against something, or the wire from the starter to the fuse block is rubbed through/grounded out. Something like that would cause the alternator to see drain and over charge. If the battery went dead while you were driving and the gauge read 16-18 volts, then the power is not getting from the alt to the battery. It's really something that I'd need to look at. If you were in the south Seattle are, I'd volunteer to look it over.

#4 HILLBILLYHARLOT

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Posted 02 December 2010 - 11:16 AM

I haven't checked the wires from the Alt, or starter yet, but I'll start there. When the link first blew, it melted and smelled horrible! I patched a hole in Alt wire this summer, maybe it's not enough... Hmm... Thanks guys I'll go check those..

#5 skishop69

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Posted 02 December 2010 - 11:27 AM

+1 for the diodes being bad. If they are, you'll still have voltage, just no current. Did they load test it at NAPA, or just spin it up and check for voltage? The alt wire runs from the alt to the main harness by the left fender, then around under the radiator and back up by the battery. A couple quick tests with a load tester and ohms check with a meter could tell you if you have a sort or weak alternator.

Edited by skishop69, 02 December 2010 - 11:33 AM.


#6 Cougar

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Posted 02 December 2010 - 12:00 PM

The voltage readings you saw in the car are too high and indicate the regulator inside the alternator is bad but the readings shown from the bench test are good. The sense wire from the battery to the back side of the alternator may have a short to ground on it and is causing the alternator to run full field output. To see if that is the case you will need a voltmeter to check things with. Using a digital meter, it is easy to read the display. To check the wiring to the alternator remove the connector on the back side of the alternator, turn the ignition switch to RUN and then check the voltage of each of the wires. Place the (red) positive probe of the meter on each wire with the (blk) negative meter probe tied to a good ground connection on the car or the negative battery post. You should have 12 volts on each of the wires if things are ok there.

#7 HILLBILLYHARLOT

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Posted 02 December 2010 - 03:50 PM

I have a test light, and a continuity tester. I checked all the wires and they all look good. I got a brand new battery because NAPA guy said it could be bad. I knew it wasn't the issue but I gladly took his new battery considering I ran mine dead :) Anyone know what to look for as far as replacing the original fusible link for the starter?? Mine was replaced with a random piece of wire last spring, so I don't know what it was originally.... 86 GL 1800...

#8 Cougar

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Posted 02 December 2010 - 05:15 PM

There are usually three different colored fusible links used in the EA 82 models. Black, red, and green. I think that is the order of their current capability also going from highest to lowest ratings. Hopefully you don't have a mixup on their positions and have a lower rated link in the position for a higher rated link. A link isn't used for the starter motor itself as the starter draws way too much current to use one for that. Starters are tied directly to the battery through the starter solenoid. The solenoid has the heavy duty contacts to make the high current switch connection for the starter motor. The fusible links tie to the ignition and accessories circuits for the car. We need to know if the trouble happens when the ignition switch is turned to the RUN mode or to the START position in order to help you pin the trouble down. You stated that a 30 amp fuse worked ok in the circuit. Is that still true? If it is then there may not be a shorting problem and you most likely just need a fusible link with a little higher rating in that position.

Edited by Cougar, 02 December 2010 - 05:26 PM.


#9 Ricearu

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Posted 03 December 2010 - 09:18 AM

There are usually three different colored fusible links used in the EA 82 models. Black, red, and green. I think that is the order of their current capability also going from highest to lowest ratings. Hopefully you don't have a mixup on their positions and have a lower rated link in the position for a higher rated link. A link isn't used for the starter motor itself as the starter draws way too much current to use one for that. Starters are tied directly to the battery through the starter solenoid. The solenoid has the heavy duty contacts to make the high current switch connection for the starter motor. The fusible links tie to the ignition and accessories circuits for the car. We need to know if the trouble happens when the ignition switch is turned to the RUN mode or to the START position in order to help you pin the trouble down. You stated that a 30 amp fuse worked ok in the circuit. Is that still true? If it is then there may not be a shorting problem and you most likely just need a fusible link with a little higher rating in that position.


starter solenoid should not pull 30A, there is a short somewhere, possibly in the solenoid itself... I would fix the start issue before throwing money at a new alternator. :)

oh and to the original poster, the "random pieces of wire" that are in the fusable links, cause car destroying fires because it doesn't break connection when there is a circuit fault.

Edited by Ricearu, 03 December 2010 - 09:20 AM.


#10 Cougar

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Posted 03 December 2010 - 10:12 AM

starter solenoid should not pull 30A, there is a short somewhere, possibly in the solenoid itself... I would fix the start issue before throwing money at a new alternator.


We aren't sure yet (at least I'm not) which fusible link may have the trouble on it, or if there really still is any trouble. The poster stated that a regular 30a fuse worked ok, for a while at least. I think even the lowest current rated link can handle 45a. So I have to ask, is there still a real problem here or if just the correctly sized link needs to be installed?

I agree with your statement about the solenoid current draw. The amount of current it needs to activate may be about 1 amp or possibly less. From what I have read of the posts I'm not sure when the fuse is blowing out. The poster talks about it failing with the starter but I question if that is really true and is why I asked if the fuse blows while the key is just turned to the RUN mode. There could be a wiring issue in the START mode somewhere but that is pretty rare. Then again, if a 30a amp fuse is working ok I don't think there is a real problem at the moment.

#11 HILLBILLYHARLOT

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Posted 03 December 2010 - 11:38 AM

Ok, update.... The fusible link in question is the closest to the firewall and when the wire that was in place of said link burned up, I had NO power to windows, and not even a click when I tried to start it. I took the car to NAPA and had the battery tested in car, and found out that the volt meter in the dash isn't reading right, it's only charging @ 13v. So the alteranator is off the hook. I don't yet know why I ran it for 40 miles and the lights & heater ran the batt dead but the car still ran. If anyone knows what that link should be so I can order one, I'll start there, then try to figure out why the accessories drained a good battery.. One more thing, I used the red link when it first burned up, and I was able to run it that way for a bit. I need to know the amps or size or whatever it is of that fusible link.... Nobody in part stores knows fawkall about subarus and it's pizzin me off!!!!

#12 GeneralDisorder

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Posted 03 December 2010 - 12:06 PM

That fusible link should be the black one on your car - it's the largest of the three (1.25 square mm cross-section), and has a current load of like 21 amps.

You definitely have a bad connection - I don't think the alt or it's wireing is your trouble because if it were then the other links would be damaged as well.

That black link is like $10 from the dealer or you can find them at the junk yards, etc.

I would start simple - verify that the connectors under the link are clean and not corroded, etc. Same with the wires going to the fusible link box, etc. That is a common point of corrosion and high resistance - it creates heat which will damage and burn up the links after a short time. My guess is that your problem is very close to that area.

GD

Edited by GeneralDisorder, 03 December 2010 - 07:06 PM.


#13 HILLBILLYHARLOT

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Posted 03 December 2010 - 12:51 PM

I agree... The large white wire that goes into the fusible link box did get hot & is discolored, I tried to pull it out, I was going to cut it and re connect it, but it doesn't come out easy and I didn't want to break the box. Thanks for the info on the link, I'll see if I can find one close. And idea how many years of subarus had the same link there in case I find an older or newer one in a bone yard??

#14 GeneralDisorder

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Posted 03 December 2010 - 12:57 PM

It does not pull out - it is crimped in place. You may have to source another fusible link box with a good crimp on the white supply side wire and then solder your wire (or new wire) to it a couple inches down. I suspect you have a corroded connection there and it's going to be a real pain to clean it and repair it. Better to find a used replacement that hasn't seen so much mud. :rolleyes:

GD

#15 HILLBILLYHARLOT

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Posted 03 December 2010 - 01:04 PM

:eek: MUD!!!! Well, I NEVER take my precious off road.... :lol: That car has seen some SERIOUS abuse from me, I am very impressed! That's the only reason I'm still a subaru fan, dispite the majority of the market subaru's have.... I am NOT a fan of hippys, yuppies or liberals ;) It has proven itself as a tough piece of iron!

#16 edrach

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Posted 03 December 2010 - 05:27 PM

I probably have the some fusible links in my "stash". Drop me a PM with an address and I'll mail you a set.

GD is correct on his assessment of the discoloration. Best bet is to replace the entire fusible link box with the wiring. Should be easy enough to find an assembly at the junkyard since that's not an item that fails very often. Find one without any discoloration in the wires leading to the assembly and disconnect everything from the other end.

#17 HILLBILLYHARLOT

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Posted 03 December 2010 - 07:45 PM

I found a few links at a boneyard, and so far, that's remedied the issue, even made the gauge volt meter read correctly. I have another black, and green and red, just in case something blows again. Now, on the the HEATER ISSUE... Fawk it's cold in that car! Since one heater hose is hot, the other warm... I'm betting it's a plugged core and I will be trying to clean it out tomorrow. Thanks for all the help guys, I called subaru, and they couldn't even tell me what link I needed....

#18 Cougar

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Posted 05 December 2010 - 03:48 PM

Due to normal wire losses the dash voltmeters can read up to around 1 volt low. As long as you know about the issue it is no big deal.

Glad to hear the new fusible links are working ok for you and you now have some spares. I noted the rating that GD stated for the black one. I though it more like in the 40 to 60 amps area. I think the alternator charging currrent runs through it but I would need to look at my manual to verify those things.

If the windows still don't work then check the other fuses in the dash and make sure they are ok. If they are good then some other checks are needed in the window circuit.

#19 GeneralDisorder

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Posted 05 December 2010 - 10:02 PM

I'm pretty sure that 21 is the *nominal* current load that the link carries. I think the larger rating is it's max - where it will blow after 15 seconds.... consider that the alt is only rated at 55 amps and there are two other links that need some of that juice.....

GD

#20 Cougar

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Posted 11 December 2010 - 02:02 AM

GD,
I checked my manual and you are correct about the 21 amps for the black link. The manual also stated that the link is designed to melt when there is 190 amps flowing for 15 seconds.

#21 GeneralDisorder

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Posted 11 December 2010 - 10:56 AM

designed to melt when there is 190 amps flowing for 15 seconds.


:eek:. Yikes - that's a serious short.

GD




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