a/c heater wire smoked

Passenger side engine compartment, under the fender area on the firewall. To the passenger side of the A/C plenum/box. You'll have to remove the coolant reservoir to get to it.

I think you need to really look at your wiring from the starter up. I would not replace the fusible link with a fuse. The fusible link will hold under high current loads for a brief period of time. depending on the fuse it will react almost instantaneous. so on high speed  fan start up you might blow a fuse but not a fusible link.

I tried to find what amp rating the fusible links are but I'm not sure the info is 100 percent, the general info on fusible link are you just install on 4 Ga smaller than the wire you are protecting

I think the 79 has 2 at the starter Not sure they may be black which I think they are rated for 100+ amps for 15 sec with a continues rating of 40 amps.

The fuse might help find the short if you have one but something was not wired correctly in the beginning their must not have been any fusible links if the wires burned up.

Fusible links look just like regular wires, except the insulation is made out of a special, flame-proof material.  The easiest way to test them is to tug on them.  A blown link will stretch like a rubber band.

http://www.autoshop101.com/forms/hweb1.pdf

http://www.madelectrical.com/catalog/fusible-link.shtml

 

 

Thanks for the help. After checking wires to make sure they weren't reversed, I discovered the problem. The tab where you plug the hot lead on was real loose. I replaced the motor and that seemed to take care of the problem. It's kind of hard to reverse the wires as the power has a rubber boot that should slip over a rubber grommet on the fan motor.                  when I pulled the old fan off to do my a c work, it worked fine. That's why I didn't replace it. After putting everything back together, I plugged in the power. It is in a spot under the fender, so you kind of have to feel for the lead to plug it in. After 35 years I guess the rubber insulation breaks down and disintegrates when you fool around with it. Plugging in the lead blindly  seems to have done it in. Morale of the story is I should ha gone the extra couple and replaced the motor, since I replaced everything else.It would have been easier to replace the fan motor when everything was out in front of me, would have saved me from melting wire and the hours trying to figure the problem out, thee burnt up resistor in the heater box, and worst of all hearing from some people telling me about constantly sinking money into my car. I don't need to hear that. Like I tell people, I've owned that car longer than I've been married. It's got seniority. Once again thanks for the response from the forum.

  

Had same issues .Replaced Resistor on top of  heaterbox gave me my 3 lower speeds on fan back. One of the spring coils got damaged.

thanks for help,but it took one young strong young man to pull call  and it opened,cable is worn out   new one is on the way,info you guys was good  you can open hood with one push for screw driver  its work  but I would only try with  tool,i could not get my hand under hood when closed but alls well  thanks again  dwa