Current draw to the headlights will increase with the addition of a relay. Which just means that the headlights will get the current they SHOULD, rather than the pitifully low current/low voltage the factory wiring delivered. In an already strained electrical system, it could result in a mild system wide decrease in voltage. But if the alt is that maxed anyway, it's time to get a bigger one.

 

Have you seen this? http://midnightdsigns.com/james/headlights.htm

I'll take some pics of my setup tomorrow and see if I can post them. I'll have to run it thru the wifes computer though...can't seem to load pics onto this stupid computer.

 

Yeah adding the relays is a must for any kinda headlights.And for dash lights you can see at night they sell led dash lights you can pick them up at radio shack around 20 bucks or less.

 

The stock wiring on the early Mustangs was just plain pathetic. By the time current winds it's way through the main harness and gets to the headlights, you're lucky to have anything over 10v....on a system that is putting out 14+v. That tells you how much resistance there is, and how much current loss along with it.

Especially when you start adding other crap with electrical loads to the car like many of us do.

 

It should not really effect the alternator at all. You need one relay for low and one for high. It doesn't matter if you have 2 or 4 headlights, because 2 headlight systems are dual filiment bulbs.

 

`q NM`