Parasitic Draw

[383mrollg]

I am seeing a current draw of 10-15amps between the battery negative cable and negative terminal on the battery. I pulled every fuse under the dash with no change.

Any ideas on where to start under the hood? I feel like it would be starter related being such high current draw. The big post I see 12v at all times which I believe is normal. the smaller wire I don't see any voltage with the key off and like .05v with key in on position is that normal? I checked the starter relay. The relay itself is grounded and the wire that goes to ground and/or safety switch shows I have ground continuity. I disconnected ballast resistor on both sides and still have the same draw as well.

70 d100 with mopar electronic ignition

Thanks

[nutz]

alt.
bad diode in alt

[383mrollg]

Replaced the alt under warranty for free. Current draw is still here. I'm about to just start going through and replacing every wire under the hood at this point.

[712edf]

I'm about to just start going through and replacing every wire under the hood at this point.

That's standard procedure for most Chrysler Corp built vehicles. What the factory didn't screw up the previous owners did.

Bucky

[BigBlockTrucks]

Maybe look into the headlight circuit and switch and the dimmer. Headlights aren’t fused. And the dimmer is on the floor where there has been lots of moisture most times.

[nutz]

15 amp is huge maybe 1.5 amp
most new cars .25
something would getting hot
aftermarket radio?
trailer brake box ?anything after market ?

[383mrollg]

One of my headlights isn't working (probably just the bulb) I could look into that. No stereo. No AC or heater. I did install the 4 wire trailer harness 15 plus years ago I could look into that as well. Now it wont start just cranks over. Have fuel and air. battery shows 12.4 but at the ballast I show only 11.9 and at the coil the same 11.9. Other circuits that require 12v are showing the same voltage as the battery but the ignition is showing now less. All I did was pull the fuses and put new ones in same size same amperage 20. Chasing gremlins!

New battery, new alt, new starter.

[383mrollg]

So truck wasn't starting. Threw in a spare coil and it fired up. What made me think of it was that I'm probing around with the key in the on position looking for 12v sources and I touched the coil and it was piping hot...after driving around for a while with the spare coil it was also really hot. I imagine there is something going on to be causing that. I'm afraid whatever it is, is going to keep eating coils.

[712edf]

Not sure what exact setup you have, I believe your truck originally had a points ignition & now has electronic.

Anyways on most Mopar ignitions of that era the coil is supposed to get 12v during cranking then only about half that when running. Too much voltage & yes the coil will burn up. But I am not sure what you have nor what is causing your coil to be hot.

They do make coils that are designed to operate on a full 12 volts.

Bucky

[712edf]

Does your coil get warm with the key OFF? Maybe something is causing it to have some voltage all the time, thus drawing the battery down.

Bucky

[nutz]

thinking you have oil filled coils ,make sure you get epoxy filled one
or your transistor in your ignition mod is failing
also make sure your ignition mod is grounded properly ....best to run a ground from the mod to the engine

[Wildergarten]

thinking you have oil filled coils ,make sure you get epoxy filled one
or your transistor in your ignition mod is failing
also make sure your ignition mod is grounded properly ....best to run a ground from the mod to the engine

With star washers (both under the lug and the bolt head) for good contact.

[383mrollg]

I have the Mopar electronic ignition. The coil has no voltage with the key off. I checked the continuity for ground on the ignition module. I have a ground wire going from the engine to the voltage regulator box and then a ground wire going from voltage regulator to the ignition module. When I touch on the box housing itself there is no ground but when I touch the bolt that has the ground wire holding it against the firewall there is ground is that sufficient?

I thought maybe my volt meter is crap so I brought one home from work and when I check for amp draw between battery and battery ground wire I'm showing .1mA so maybe I fixed the draw issue... About to grab another volt meter from work to triple verify..

When the battery is all hooked up I checked the voltage to both sides of the ballast resistor and the coil and zero volts. I then removed the ground wire from the battery and went from battery negative to the ballast both sides and the coil positive and I show 10v to all three does that even make sense?? Also with the battery all hooked up I show 12v to the alternator with the key off is that normal?

[nutz]

yes if you remove the ground you will have 12v (battery voltage )to your resistor
and should have battery voltage to your alt
not sure what you are trying to fix here
does your battery go dead over a couple of days (parasitic draw)
or is it your coil gets hot

[383mrollg]

The parasitic has been a problem for years. But the truck was sitting for a long time so I never addressed it until now. The hot coil issue is new. I searched the forums and found a solid video on complete diagnosis on Mopar electronic ignition I will go through that this weekend and see if I find anything

[383mrollg]

Parasitic draw is gone must have been one of the many wires I replaced in the ignition system. The coil is still super hot. I checked the voltage at the coil when the engine is running and it's all over the place between 2v and 13v randomly changing. I'm thinking this is the voltage regulator.

Thanks for all the input, much appreciated!

[Wildergarten]

I searched the forums and found a solid video on complete diagnosis on Mopar electronic ignition

Please post that link.

[nutz]

2v to 13 on the positive side ?
it would have to be ballast resistor or ignition switch (or a bad connection)
just start back tracking with a voltage meter till you find a stable voltage
or easiest way is with a temp gun and look for heat in your switch and connections

[Wildergarten]

2v to 13 on the positive side ?
it would have to be ballast resistor or ignition switch (or a bad connection)
just start back tracking with a voltage meter till you find a stable voltage
or easiest way is with a temp gun and look for heat in your switch and connections

I have never thought of that, but it's an awesome idea (only got one last year to measure the woodstove). Thanks!

[383mrollg]

https://youtu.be/tVja7UctgIw the link you requested above

I have a 2 prong ballast resistor after checking again I'm getting 13.3v on the right prong and the left prong is bouncing around like the coil was showing. I need to go through and make sure I have everything wired up correctly.

It looks like the left ballast wire is tied into the coil positive and also a red wire into the firewall which is also connected to the orange wire going to alternator field.

The new alt I got is a dual field the same as my old one but the field physical locations were different on the new alt vs old so I wasn't sure which one goes where. The other field wire is green and I believe that is supposed to be a ground to the voltage regulator? I need to go through the factory wiring diagrams and also the electronic ignition upgrade diagrams...