fusible link smoking
- Thread starter 67barracuda
- Start date
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67barracuda
Well-Known Member
Tried disconnecting pink power wire to brake switch. No difference test bulb still lights
I wonder where that tail light is getting power from. Maybe headlight switch? Or chk/trace the wire from brake light switch?
67barracuda
Well-Known Member
OK, maybe a clue. If I disconnect the pink and yellow connection to the rear harness by the kicker panel, bulb doesn't light. I believe this part off harness feed the license plate, gas tank gauge, and trunk light.
Which plug ( 2wire pink/yellow) or the single pink continues to rear? Chk those connections with your bulb tester.
Also do you have schematic? If not go to mymopar.com and download.
Also do you have schematic? If not go to mymopar.com and download.
67barracuda
Well-Known Member
Ok if I reconnect the pink /yellow harness and remove the trunk light and ground, test bulb doesn't light on frame or tail lights.
I also reconnected the brake light switch pink wire.
Not until the trunk light and ground is reinstalled will the test bulb light. If I use the test bulb in the heavy load setup, both wires twisted together, when checking the tail light and frame, test bulb doesn't light, but the trunk light comes on. Has the trunk light just been reaching for a ground through everything and because I was check with low load wire the test bulb was lighting. What explains the tail light coming on in the really case?
Maybe I don't have a short?
I also reconnected the brake light switch pink wire.
Not until the trunk light and ground is reinstalled will the test bulb light. If I use the test bulb in the heavy load setup, both wires twisted together, when checking the tail light and frame, test bulb doesn't light, but the trunk light comes on. Has the trunk light just been reaching for a ground through everything and because I was check with low load wire the test bulb was lighting. What explains the tail light coming on in the really case?
Maybe I don't have a short?
67Dart273
Well-Known Member
That is what I've been trying to get at............
When you do this testing you are attempting to duplicate the car "as parked" as in, all doors shut, everything turned off.
With everything turned off, there should be NO current draw. If you have your trunk light all hooked up AND THE TRUNK OPEN, then the trunk light SWITCH is completing the circuit for the trunk light.
So the question is, "if" it is something in the trunk lighting, how could this have fried your fuse link?
Answer? Doubtful anything back there DID
67barracuda
Well-Known Member
The battery is mounted in trunk and didn't even think about the trunk light at all when doing the testing. I agree the nothing back there caused the fusible like to burn.
I'm still leaning towards the alternators second field not being ground out. The reason is that I don't have the 70's style electronic voltage regulator from the alternator second field.
Everything I read on the net says that with a single field alternator wiring system if you run a dual field alternator you must us a 70's style voltage regulator off the second field or ground the second field to the case or motor. If not you will burn the fusible link.
What do think?
I'm still leaning towards the alternators second field not being ground out. The reason is that I don't have the 70's style electronic voltage regulator from the alternator second field.
Everything I read on the net says that with a single field alternator wiring system if you run a dual field alternator you must us a 70's style voltage regulator off the second field or ground the second field to the case or motor. If not you will burn the fusible link.
What do think?
67Dart273
Well-Known Member
The second field has nothing to do with this, unless the alternator HAS A PROBLEM. This happens because there has been rebuilders who don't "do" things "as factory."
One scenario is that one brush (field) becomes grounded, either a broken insulator, a bad rotor, or A REBUILDER who left out the insulating washers.
A related version of this is a rebuilder who DOES ground one field and sells a 70/ later unit as if it's a 69, but leaves BOTH terminals with their spade connectors. This means if you "gamble" and hook the field up to the wrong terminal, it's a dead short for the regulator. This should not burn the fuse link, but it WILL burn up the VR.
This is easy to check. Just put your meter on resistance (ohms) and check for continuity between the two field connections (should be a low reading, 4-6 ohms or so) and then check from each field terminal to the alternator case. They should be OPEN no continuity.
Take a REAL good look at the alternator output stud. Is it loose? Insulator OK? Check it for resistance. Should be open (infinity) one direction, reverse the probes, should be a low resistance.
In this testing you are doing, you are trying to make the car exactly as "I drove it in here and parked it."
If the alternator does not show a light on your test lamp, hook it back up.
USUALLY something so bad that it burns the fuse link will show up pretty dramatically........damaged harness, burned connections, smoke, smell, etc.
Inspect your ammeter VERY closely if it's still connected.
One scenario is that one brush (field) becomes grounded, either a broken insulator, a bad rotor, or A REBUILDER who left out the insulating washers.
A related version of this is a rebuilder who DOES ground one field and sells a 70/ later unit as if it's a 69, but leaves BOTH terminals with their spade connectors. This means if you "gamble" and hook the field up to the wrong terminal, it's a dead short for the regulator. This should not burn the fuse link, but it WILL burn up the VR.
This is easy to check. Just put your meter on resistance (ohms) and check for continuity between the two field connections (should be a low reading, 4-6 ohms or so) and then check from each field terminal to the alternator case. They should be OPEN no continuity.
Take a REAL good look at the alternator output stud. Is it loose? Insulator OK? Check it for resistance. Should be open (infinity) one direction, reverse the probes, should be a low resistance.
In this testing you are doing, you are trying to make the car exactly as "I drove it in here and parked it."
If the alternator does not show a light on your test lamp, hook it back up.
USUALLY something so bad that it burns the fuse link will show up pretty dramatically........damaged harness, burned connections, smoke, smell, etc.
Inspect your ammeter VERY closely if it's still connected.
67barracuda
Well-Known Member
Ok I'll check it tonight.
Originally when the fuse went, car was not running but the key was in run position. I flicked the kill switch at the battery in the trunk and that's when it started smoking.
I put my spare set of stock gauges in when redoing the dash, so I'll look over the old ammeter tonight for any damage.
Thanks for all your help.
Originally when the fuse went, car was not running but the key was in run position. I flicked the kill switch at the battery in the trunk and that's when it started smoking.
I put my spare set of stock gauges in when redoing the dash, so I'll look over the old ammeter tonight for any damage.
Thanks for all your help.
67barracuda
Well-Known Member
Alternator checks out ok. Continuity between the two field on 200 ohms scale reads 55.7 and open to the case. Stud nice and tight and doesn't light the test bulb. Hook it back up and stud will light test bulb, case will not. Working as it should.
Ammeter looks fine and tested with AAA battery. Needle still move back and forth.
The one in there now looks just as good.
Ammeter looks fine and tested with AAA battery. Needle still move back and forth.
The one in there now looks just as good.
67barracuda
Well-Known Member
Maybe is was in the original dash harness that I replaced?
The original harness was cut/spliced and they rerouted a fusible link through a small hole in the firewall because the original one might have been burnt at the bulk head. Maybe that wire over the years had a bare spot and shorted on the firewall?
The original harness was cut/spliced and they rerouted a fusible link through a small hole in the firewall because the original one might have been burnt at the bulk head. Maybe that wire over the years had a bare spot and shorted on the firewall?
When my fuslink went it had something to do with the used alternator that I had JUST installed. Can't remember exactly the issue but replaced alternator and replaced link. All under Dels direction. Lol
Fyi we have MP elec.ign.
Fyi we have MP elec.ign.
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