Turn key to on position, harness starts to melt

[69rtsetracpac]

Okay wiring guru's here's what I have, 69' Charger R/T SE, 440, 4 speed, built this car back from a rusty bare tub over the last 10 plus years, has firecore RTR dis. new engine harness, new dash harness, new Year One switch housing with old key insert. Turn key to the left (accesory pos.) every thing fine, lights, blinkers, wipers you name it, every thing seems to work okay. Turn key to the on pos. and the fusible link wire from the bulkhead connector to the switch relay gets hotter then hell in less than five seconds, if you left it on my new wiring would melt to the ground. Originally had old used switch, tried new Year One switch, no change. Every one around me is scratching their heads. Any one?

[Kern Dog]

The ammeter may have fried!

[69rtsetracpac]

?

[BLK 68 R/T]

Sounds like a dead short to ground. Did you have the dash cluster rebuilt? the amp gauge should be fully insulated from the housing, if the insulator strip was not installed across the back of the posts, you will end up with a short to ground.

[70 sublime]

I would not think it is he amp meter shorted out as it is hooked to the battery before the key ( would ark when you hook up battery if it was shorted)

Sounds like something in your key switch is not happy or something that is only turned on when the key is turned to run position like the ignition parts

[Pete in NH]

I would not think it is he amp meter shorted out as it is hooked to the battery before the key ( would ark when you hook up battery if it was shorted)

Sounds like something in your key switch is not happy or something that is only turned on when the key is turned to run position like the ignition parts

I agree, the problem is something after the ignition switch. Time to get out the wiring diagrams and disconnect one circuit that the ignition switch controls at a time until you find the problem area. I would put a temporary 20 amp fuse between the battery negative post and battery cable. Have plenty of spare fuses. That way you will not risk your new wiring until you find the problem.

[69rtsetracpac]

Thanks for the replies, the dash cluster was not rebuilt, just put new decals on the faces. I'am not good at elec. problems so this is frustrating. Now I'm second guessing weather the amp gauge wires are hooked up to the right terminals, how about if I just unhooked   those leads to the amp gauge to eliminate that question? The new distributor called for eliminating the balast resistor on the fire wall and combining those three wires (2 blues and 1 brown) one of these wires(blue) gets hot. the "new" wire from these three goes to coil pos. Have also tried different switch relay.

[Dino]

You can have the red and black wires swapped on the ammeter and it would still be fine, as long as they are snug and there is no corrosion buildup. Resistance causes fires.

Did you mate the three wires at the resistor? If one of them is not seated right in the bulkhead connector it will cause problems.

Disconnect the battery and check all connections, all the ones in the bulkhead connector, the cluster, and the ignition switch. Look for melted insulation and corroded or blackened terminals.

[69rtsetracpac]

Yes, the wires were combined at the resistor. Amp gauge is hooked up correctly with insulator. I will check connections, but as far corrosion... all wiring is new. Thanks for your replies.

[Nacho-RT74]

I put my bid on the wire feeding the alt field or atl field insulator got broken

[69rtsetracpac]

Can you elaborate on that nacho? Just so I have offered up as much info as possible, my alternator is a new one from Mancini, stock looking by Powermaster, I don't remember what amp. but nothing crazy, just told the salesman I wanted a good stock looking alt. to plug in. My wiring harness for the alt. has three connections, 2 stud type and 1 spade, the alt. has 4, 2 stud and 2 spade, the spade I'm not using I ground to the alt. case? Thanks.

[John_Kunkel]

The new distributor called for eliminating the balast resistor on the fire wall and combining those three wires (2 blues and 1 brown) one of these wires(blue) gets hot. the "new" wire from these three goes to coil pos.

Forget all references to the ammeter, it's upstream of the ignition switch, the problem is downstream from the switch.

Which of the blue wires is getting hot? Trace where it goes. A blue wire from the firewall disconnect originally goes to the ballast and branches off to the voltage regulator.

Assuming you have the original-type '69 regulator, your '69 doesn't take the alternator with two spade connectors for the fields, a '69 alternator should have only one spade connector and the large threaded stud. Sounds like Mancini sent you a '70-later alternator.

the spade I'm not using I ground to the alt. case?

That's likely your problem, you hooked a hot wire from the ignition switch to ground.

[69rtsetracpac]

John thanks for the reply, I don't have a regulator, it is built in to the Firecore distributor. The harness would get hot before I ground the alternator wire, I was told to do that as a possible fix. Thanks

[Dino]

??

Firecore distributors come with a built in ecu, not a built in regulator. You still need to run one of those. Did you mean to say the alternator has a built in regulator?

[b5blue]

  A 69 would not have an Electronic Control Unit for ignition it had points. All ignitions for Mopar have "START" and "RUN" at the switch, start bypasses the resistor when cranking the engine and switches to run to use resistor. So if your new harness is "correct" for 69 you have nothing for an ECU. If you bought the modified engine harness for ECU it would have a big rubber plug in for an ECU. (So tell us what engine harness you have.) Your voltage regulator is a square box on the firewall that controls ALT. output.
  John is spot on, pull all fuses and check the problem again. IF gone put one fuse in and check again. Repeat until problem returns...that will be where to find the issue.

[69rtsetracpac]

Ok I wasn't thinking when I was typing in my last post, I have stock points type harness, with stock type(new) voltage regulator on firewall, just to make sure I have it wired correctly, (remember I started with a bare shell of a car), their is 2 blue wires(1 has white stripe)that go to the spade connection on voltage reg. and a green wire that goes under a screw on the other side correct? Just for the heck of it I removed all connections to alternator and turned key to on and the harness did not get hot.Thanks all for your input.

[Nacho-RT74]

About my bid, what Kunkel said points out about the same I told. Due a broken contact or wrong wire hook up, the deal is the same. Run circuit ( represented by the blue wiring on engine harness ) is getting grounded, so that's the reason why you got the short just right on that moment.

BTW, dual field alts are dual prong and one stud. Blue wire on alt prong is positive RUN circuit. Which if is hooked up to a grounded source, will short out as soon you put the ign in RUN.

Blue wire on engine harness to alt brush can be connected on ANY of the alt prongs... As far these prongs are correctly isolated from chassis... Which in a correct and good conditions alt, IT MUST

This is for dual prongs alt and elect regulators

On single prong alts and mech regulators, the positive source to alt is green wire instead coming out straight from regulator, since the negative on this older system is sourced by a grounded brush without a prong ( hence just one prong on these alts )

[Nacho-RT74]

If you are using the alt you described with the stock 69 regulator system, something is unmatched here.

Two studs ? I guess one large size and the other thin one ( which sometimes is labeled ground )


Is true on dual prong alts and mech regulators setups one of the prongs must be grounded because these alts gets both isolated. Alt needs both fields to generate power inside. But becarefull if you did something wrong on that.

On laters systems both fields are wired instead one of them grounded this is because laters gets  NEGATIVE  field regulated from regulator and constant positive from ign switch run circuit. Earliers gets constant negative being grounded and regulated positive

On both setups the regulated source is represented by the green wire, but field polarity changes