69 300, melted wiring and blown heater blower switch--solution?

BigBird69

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Taking the dash apart to fix a few issues and get the AC/heat working (regular AC, not Temp II), discovered melted wiring and a blown-through blower switch (yikes!). I got a NOS switch, and can get the wiring done, but what about the resistor? It looks fine, and a NOS one is like $300. Is there a visible way to tell if it's no good? Is a 50-year old one in a box worth the expense? This is beyond my knowledge base

Blowerswitch.jpg


Heaterwiring-5.jpg


Heaterwiring-6.jpg


Resistor-3.jpg
 
Your resistor was not the problem. Run a draw test on the heater blower motor. Odds are it is shorted and that is what toasted your switch. Other possibility is that the plug got corroded on the switch and the extra resistance caused the meltdown. As long as the resistance wires are not burned off, the unit is still good. If that is your unit in the photo, it is in good shape.

Dave
 
Thanks Dave, I'll check the motor. Sixpactogo said the same thing. Nice to have these boards with helpful suggestions!
 
The resistor is fine - if it's intact, it's doing its job as designed. The load through the switch that melted things is coming from somewhere else, as noted above.

You could even measure the resistances with an Ohm-meter - three speeds on your switch - so low will be the highest resistance, and high will be the lowest resistance and the medium somewhere in the middle. At least I think that's how it goes - either that or the switch uses combinations of 2 or 3 coils... not sure.
 
When I see a connector like that melted one, it usually means the heater blower motor is drawing too much current - the original blower motors are notorious for deteriorating in that respect rapidly. Replace yours with an identical replacement from Bosch or other brands such as perhaps 4 seasons. This is primarily the same reply as Dave above is suggesting.
 
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