I have numerous additions on the electrical system on my 68 convertible. I have the original harness that has not been hacked on. I am adding on a stereo system with 2 amps, power windows, additional guages, power locks and car alarm that will run off a Painless aux fuse box (amps are directly off my Optima battery). I have a 3G alternator rated at 130 amps. Will I run into problems with my original harness with this setup?

I am also running and EFI system. I plan on eventually putting in a new harness but don't want to do it now.It would likely be a longer term wiring project and I would rather drive the car when it gets out of the body shop thanlook it in my garage for the next 9 months..

 

Pretty much the way I did it too. Ran all the base car off the original wiring and ran the mods off a secondary fusebox fed from the battery. I'm not expecting any problems with the base wiring.

 

Yeah, if you aren't pulling any more amps through those old wires than you were previously, then you should not have a problem. Just keep it in the back of your mind to replace those 40 year old wires in the near future. That's what I am going to have to do, and I dread the day I start on it. Especially the ones under the dash because my 63 year old body is getting stiff on me.

 

It is recommendedthat you not take"VIAGRA" at least 24 hours before attempting to replace a 40 year old wiring harness in a Classic Mustang. It says so on the label, somewhere.

 

Thanks guys for the confidence. I will have to check out the Viagara before I start. I was reading the thread about a one wire alternator and started to get a little worried. It looks like new wiring will be my project for November 07' through March 09'. But then again a G-Bar rear suspension would be much more fun ............ HMMMMMMMMMM

 

If you haven't already done the headlight relay mod, you might consider that in the interim. The amp draw with the headlights on is the single biggest item that taxes your basic wiring. Heater and horn would be second & third. By using relays in your headlight circuit, you remove that big current load from your underdash harness and just run a small signal line.

 

The headlight circuit is on the to do list as well. As far as the horn goes I did a flaming river column change and could never get the horn to work after that. One more thing for the to do list. I am not even sure how I would tackle that one though.

 

jamesw is right and to me they are alot briter too.soaring i believe you can get a oem replacement one which has all the conectors already on it.

 

Oh, I know I can get an OEM replacement new harness for under the dash, or I can even go the painless route, but laying on my old back on the hump and working upside down is just getting a little difficult for me.

 

find you a dumb cocky young buck like me to do it for you. my step dad is 60 and hes always having me do things for him because he cant.