Alt and Electrical Issues

OK guys, sorry to be annoying but I have another issue I need help with.

I actually have a few questions to ask but they are all in the electrical realm so I thought I would lump them together.

1) I installed LED tail lights on the jeep. The brake lights and turn signals work unless the headlights are on. If the head lights are on neither the brake or tail or turns work. I put a voltmeter to them and without the headlights I was seeing a little over 12 volts. when I turn the headlights on I saw the voltage drop to around 11 volts. Is this 1 volt drop causing the LEDs to not go on? If it was a short, or not grounded properly I wouldn't be getting any volts at the LEDs right? Or is my thinking on that wrong? I'm thinking maybe my alt is just not giving enough juice with the headlights on. Again is this wrong thinking? Any help on this would be great!

2) Next question is, whether its the alt or not messing with the LED's I want to upgrade my alt to a Delco. After reading up on MAD I believe I'm going to go the 3 wire route along with their wiring kit. I don't know, however, how big I should go? I would like a decent winch in the future, as well as some KC/spotlights, and maybe a decent stereo, and I do have the HEI unit and the LED tail lights, nothing else I can think of that would draw a lot of amps. Will 100 amp 12si be good enough? or should I go 140 amp? I don't want to sell my self short on power. Also will I need an aftermarket bracket to mount a new alt? Any mods I would have to do to make it fit? Again its a 1973 304.

3) I think since I will be doing this upgrade I might as well put in a new wiring harness, figure if I'm putting a higher output alt I should make sure it has good wire for all the extra juice Also will take any grounding issues or shorts I might have out of the equation, which I'm sure there is as the PO didn't seem to believe in neat wiring. Question is painless or ez? Is the ez just as good as the painless? Or is the painless worth the extra money? Obviously I'll be getting the 20 circuit. What do you all think?

Thank you all for your advice in advance!!

 

100 amp would work you will rarely if ever use all those amps...id make my own harness but thats me personally i think painless is way overpriced. have no exp with ez so cant comment. good luck

 

http://www.superbrightleds.com/pdfs/load_resistor_info.pdf

Is this the type of LED you are using?

 

I installed the EZ harness. It is pretty easy as long as you take your time and work through the diagrams. I have no experience with the Painless, but I think the EZ is probably comparable, and much cheaper.

 

Easy test: Do the stop lights and indicators function correctly with regular bulbs?

Do you have the optional ammeter? If I went to an oversized alternator, I would switch to a voltmeter, and modify the wiring so that the charging circuit stays in the engine compartment. See the MAD site for some discussion of this.

Can't comment on the relative merits of a 10SI vs. a 12SI. If it were mine, I'd likely go with a 10SI - smaller, cheaper, and sufficient.

JMO - unless your harness is hacked up or badly burnt, swapping to a new harness won't be the best use of your time and money. Fixing these wiring harnesses is not hard.

 

Yeah I was thinking of doing my own harness, but I don't have the expertise so im a little scared of it. Ez looks good and is good price but I've heard more of painless

 

The lights the PO had on there were trashed so I don't know, they we're smashed and busted all up. Ill see what I can do to test a but though.

Yeah I have the amp meter, ill check the MAD site for that upgrade.

The wiring under the dash is pretty hacked up, lots of splices most with different color wires, its pretty ugly down there. I think it would best to redo it all.

 

no i installed these http://www.jeep4x4center.com/rugged-ridge-led-tail-light-set-12403-84.html

 

I cant comment on the issues, but can say there are a few companies that sell 100 amp 12si's for cheap.
http://www.jegs.com/i/JEGS/555/10120/10002/-1?CT=999
I just put this one on this summer. It is way overkill and has no problem running the electric fan, heater, lights and wipers at the same time. I used the alternator bracket from a amc hornet with a 232, and cut and rewelded it to fit

 

For the record, this is the junkyard 78amp 12si, not the Jegs 100amp.

 

awesome pics thanks bigjohn....thanks everyone for all you help and suggestions!

so ive gathered that a 100 amp alt is enough to run a winch.....i need to test my tail/brake/turns with regular bulbs, still working on that haven't had time this weekend. Like i said to Tim my harness is pretty hacked up the, PO did an awful job in there so i do feel i need to replace the harness....but maybe i will try and make my own....no better way to learn then by jumping in head first right??

if you all have more suggestions fell free to keep them coming! i need all the help i can get

 

I like the Delco CS series for alternators. The 105 amp unit puts out more juice off idle than the old 63 amp type did at highway speed.