electrical meltdown, any ideas where to look for cause
#335309
06/01/09 05:05 PM
06/01/09 05:05 PM
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nates69b
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I need help please, I left the car show sunday, driving down the road my horn suddenly started to blow, I tapped the horn button and it stopped. This has happened before and I thought it was just the button, I shut the car off, after going to get a bite to eat, went to start it up and nothing, It wouldnt crank no lights no power of any sort. I found all the wires going to the horn and horn relay melted and fried. Also, the fusible link to the box was broke and fried. It had a new year one engine harness, now its shot my question is does anyone have any ideas on what caused it and do you think any other elctrical components are damaged, I am going to order a new engine harness tonight. ANY INSIGHT IS APPRECIATED and HELPFUL as wiring is not my favorite thing. nathan
Last edited by nates69b; 06/01/09 05:57 PM.
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Re: electrical meltdown after Mopars in the Park
[Re: nates69b]
#335310
06/01/09 05:16 PM
06/01/09 05:16 PM
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nates69b
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another picture, this one of the horn relay
Last edited by nates69b; 06/01/09 05:21 PM.
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Re: electrical meltdown after Mopars in the Park
[Re: nates69b]
#335311
06/01/09 05:16 PM
06/01/09 05:16 PM
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nates69b
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Re: electrical meltdown, any ideas where to look for cause
[Re: nates69b]
#335312
06/01/09 07:22 PM
06/01/09 07:22 PM
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Lincoln Nebraska
RapidRobert
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Disconnect either batt cable 1st & with your VOM I'd check continuity at the horns and the horn relay & pull all wires from them. You have(most likely) a dead short(to ground) & I'd start at the rear half of the bulkhead where the fusible link goes in & trace downstream from there till you find it(follow the burnt/melted insulation) till you find what has grounded which shouldn't be & do check your ammeter.
live every 24 hour block of time like it's your last day on earth
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Re: electrical meltdown, any ideas where to look for cause
[Re: nates69b]
#335314
06/01/09 09:27 PM
06/01/09 09:27 PM
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SoCal
68HemiB
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From the photos, it looks like the burn goes all the way out the hot wire to the horn relay. If that is a correct statement, you have a dead short out there (at or in the relay). Wires don't melt beyond the point of a dead short, they melt the run of wire from the dead short back towards the source of power.
Down to just a blue car now.
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Re: electrical meltdown, any ideas where to look for cause
[Re: MNobody]
#335316
06/01/09 10:23 PM
06/01/09 10:23 PM
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nates69b
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Quote:
I had a 70 Dart, the horn ring in the steering wheel shorted out and fried the wires all the way to the horn's just like you described.
thats kinda what Im thinking too, I just dont want it to happen again, Its gonna take a week or so to get a new harness from year one so Im hoping to get some suggestions on what to look for.
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Re: electrical meltdown, any ideas where to look for cause
[Re: MNobody]
#335318
06/02/09 12:20 AM
06/02/09 12:20 AM
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SoCal
68HemiB
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In regards to a melted horn wire in the steering column (which is NOT the problem reported by the O.P.), remember that the job of that portion of the circuit is to find a ground. Absent other problems, a wire shorted to ground in that part of the circuit simply annoys you with a constantly honking horn. It takes a problem elsewhere (like out at the horns or horn relay) to feed unloaded current up that wire and melt it. The failure cannot simply be caused by a shorted horn wire in the column.
Down to just a blue car now.
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Re: electrical meltdown, any ideas where to look for ca
[Re: RapidRobert]
#335319
06/02/09 02:29 PM
06/02/09 02:29 PM
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Santa Cruz, California
Lefty
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Quote:
Disconnect either batt cable 1st & with your VOM I'd check continuity at the horns and the horn relay & pull all wires from them. You have(most likely) a dead short(to ground) & I'd start at the rear half of the bulkhead where the fusible link goes in & trace downstream from there till you find it(follow the burnt/melted insulation) till you find what has grounded which shouldn't be & do check your ammeter.
I'm currently replacing the dash harness on a customers car that did the same thing. The wires from the back of the fuse block melted completely and no fuses or fusible links blew.  At this point it looks like the headlight switch because it's one of the few items with a direct battery feed. The lighting fuses are after the switch.  It's not a Mopar, so yours may be different. 
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Re: electrical meltdown, any ideas where to look for cause
[Re: 68HemiB]
#335320
06/03/09 08:44 AM
06/03/09 08:44 AM
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Joined: Jun 2008
Posts: 1,822
Colorado
denfireguy
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Quote:
In regards to a melted horn wire in the steering column (which is NOT the problem reported by the O.P.), remember that the job of that portion of the circuit is to find a ground. Absent other problems, a wire shorted to ground in that part of the circuit simply annoys you with a constantly honking horn. It takes a problem elsewhere (like out at the horns or horn relay) to feed unloaded current up that wire and melt it. The failure cannot simply be caused by a shorted horn wire in the column.
You have two problems and I suspect the column issues were there for a while and are not related. As the previous poster said, the melted column wires would just honk the horn not burn up the rest of the wiring.
I would suspect a bad horn relay with an internal short.
Craig
2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado
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