orange wire started on fire
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Instructor
Joined: Apr 2016
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orange wire started on fire
was out in the garage tonight making sure my car was working properly because i just finished getting my alternator working so i was running some tests to make sure it was doing good and when i went to start it the ampmeter went to -40 and the engine didnt turn over and i saw two things smoking in the engine bay and then it caught fire a little but luckily i put it out quickly and all that happened was this orange wire started burning in 2 spots. its connected to the horn relay. anybody know why this happened? The alternator that i just got working is a cs130 is that the culprit?
Instructor
Joined: Apr 2011
Posts: 167
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From: Jacksonville Florida
Can you include a pic showing the wire that burnt? It takes a lot of current to light up a wire that quick. Sounds like something isn't wired correctly or there is a short to ground that is not fuse protected. Do you have a new or repaired alternator?
-Rick
-Rick
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Instructor
Joined: Apr 2016
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i have a alternator that a buddy gave me and i got it tested and it works fine. ill take a picture tomorrow
Thread Starter
Instructor
Joined: Apr 2016
Posts: 166
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ive been doing some reading and 2 of my fusible links blew could this be because my new alternator made to much power for them to handle? if thats what it is coukd i just replace them with higher gauge fusible links.
Le Mans Master
Joined: Jan 2001
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That's doubtful. And, in any case, the fusible links should not just start burning. I have a 140 amp CS-144 and I'm not melting fusible links.... amps are not just created by the alternator, there has to be a "demand". Can you trace that orange wire and tell us where it goes? And the picture of course.
What year model is your car? Didn't see any profile info?
What year model is your car? Didn't see any profile info?
Last edited by carriljc; Sep 8, 2017 at 10:45 AM.
Instructor
Joined: Aug 2017
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orange wire
I dont think the horn relay wiring is orange on a c3. The orange wire that goes to the alternator is a voltage sence wire. Usually goes to the two prong plug on alternator, i believe its wired directly to accesories fuse in panel, its used to tell the alternator how much power it needs to make after car is running and things are turned on. Sounds to me like something is shorted and you moving the wires when hooking up alternator has caused a wire that is skinned or fraid to touch something such as a ground or body/chassis connection. First check fuses to see if anything else has blown, may help determine what happened. Check wiring from firewall plug, there should be two sets, one goes down towards starter and tranny(has all electrical for both) and one set heads towards alternator. If fuseable links burnt from starter then something in wiring from there on has shorted. Verify all connection from alternator, specifically the one that bolts to b+ on alternator, that usually goes down to starter and may have burnt on exaust somehwere, there is a tie off that keeps them from hitting exaust and it may have come loose when working on alternator.
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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You have to find the root cause of the wire burning.
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From: South Western Ontario
It sounds like a fusible link for the ammeter. Is the orange piece of fusible link wire connected to a black wire?
If it is, then it could have been the ammeter or ammeter wiring shorting.
You did say 2 fusible links, so possibly a main link failed first and then the ammeter carried all the current causing it to fail. The -40A on the ammeter indicates the current was flowing towards the horn relay so look for the short in that area.
Did you upgrade the alternator or is the one you're using the same as the stock one? Any upgrade in charging current capacity should include wiring upgrades to handle the extra possible current.
If it is, then it could have been the ammeter or ammeter wiring shorting.
You did say 2 fusible links, so possibly a main link failed first and then the ammeter carried all the current causing it to fail. The -40A on the ammeter indicates the current was flowing towards the horn relay so look for the short in that area.
Did you upgrade the alternator or is the one you're using the same as the stock one? Any upgrade in charging current capacity should include wiring upgrades to handle the extra possible current.
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
That is correct, only a dead short would cause what you are describing. Check the new wires connected to the new alternator.
Better yet take the alternator in to a electrical shop and have them look at it, sometimes the diodes in the rectifier assembly go bad.
Good luck
Better yet take the alternator in to a electrical shop and have them look at it, sometimes the diodes in the rectifier assembly go bad.
Good luck
Thread Starter
Instructor
Joined: Apr 2016
Posts: 166
Likes: 6
It sounds like a fusible link for the ammeter. Is the orange piece of fusible link wire connected to a black wire?
If it is, then it could have been the ammeter or ammeter wiring shorting.
You did say 2 fusible links, so possibly a main link failed first and then the ammeter carried all the current causing it to fail. The -40A on the ammeter indicates the current was flowing towards the horn relay so look for the short in that area.
Did you upgrade the alternator or is the one you're using the same as the stock one? Any upgrade in charging current capacity should include wiring upgrades to handle the extra possible current.
If it is, then it could have been the ammeter or ammeter wiring shorting.
You did say 2 fusible links, so possibly a main link failed first and then the ammeter carried all the current causing it to fail. The -40A on the ammeter indicates the current was flowing towards the horn relay so look for the short in that area.
Did you upgrade the alternator or is the one you're using the same as the stock one? Any upgrade in charging current capacity should include wiring upgrades to handle the extra possible current.
Thread Starter
Instructor
Joined: Apr 2016
Posts: 166
Likes: 6
That is correct, only a dead short would cause what you are describing. Check the new wires connected to the new alternator.
Better yet take the alternator in to a electrical shop and have them look at it, sometimes the diodes in the rectifier assembly go bad.
Good luck
Better yet take the alternator in to a electrical shop and have them look at it, sometimes the diodes in the rectifier assembly go bad.
Good luck
Instructor
Joined: Aug 2017
Posts: 140
Likes: 19
In your last pic you are holding a terminal, where is that terminal suppose to go??? Is that the alternator positive? And the black terminal in the background negative to alternator?
Last edited by san; Sep 8, 2017 at 09:36 PM.