Heater Fan Switch Shorting....?????

[SWINGSAX68]

OK so I'm leaving from the Music Bldg. to go home and sleep, warming up my truck and my fan is blowing cool air at me, no prob shut it off until its warm then switch it back on for heat BRRRRRRRRRRR....when I shut it off I see a flash....blown fuse....so i get in there and replace the Air Con fuse which was busted.....I get back to my place and for sh!ts and giggles I start switching the fan off and on...just to check it out, make sure everything is fine and dandy. One time towards full blast and my dash lights blink off and on quickly....then back to off and another flash of my dash lights....last time to on position and fuse blows again. What happened?????
How can I find this short. I checked my wires, it seems that a larger grey wire comes from the wireing harness to a plug for the switch juice (the grey wire may just be painted on from painting my dash a long time ago grey) Also there is a smaller grey wire that goes to the light for the DEF-FAN-HEAT indicator. I assumed it was for this so I hooked it up as such. Why is this affecting my dash lights. ALSO.......the plug end from the fan switch plugs into the heater box into what seems like a little plastic support with two bolts on either side to mount it on the box.....mine is broken and the plug is loose, could this be my short, jiggleing around and making contact with the box???? Also if I am correct this plug has a small coil at the end, what does this little coil do????
Thanks guys I hope I described everything correctly and I hope you can help me out.....this really annoys me cause I just got my new heater core and my heater was working nicely until now.
-Roger

[bobbys1967]

If I read your post right, the coil at the end of that plug is the resistor for the lower speeds of the blower motor (there are actually 2 coils). The base of that resistor rots and it will ground on the heater box. It sounds like this is your problem. I had the same problem except the plug and the resistor are inside the heater box as it is factory A/C. These are about $20. I actually fixed mine with JB weld. Hope this helps you fix your problem.
By the way, I just finished puting a painless wiring harness in my truck and it was the best thing I've ever done to it. I used to have all kinds of wierd electrical problems. NO MORE!

[Sweet72]

That little thing mounted with two screws on the heater inner plenum is a blower motor resistor. If it's broken and shorting out that's where your prob. is. You should be able to find a replacement from one of the fine parts suppliers on this board.
-Sam

[Beefcake]

I just had sorta the same problem. My trucks kinda a beater though, so instead of replacing a bad design, I put in a spdt (single pole, double throw)switch. You loose one setting on the fan, but who needs 3 speeds anyway- high and low works just fine. Brown wire is hot on connector, other 3 wires control the speed. High amp switch only cost 6 bucks. .