Heater Blower Resistor

[fordman]

i dont think you can plug them in backwards on the ressitor. i think its a three pronged plug. unless you missed the top prong and put the plug on upside down. i guess that could be called backwards i suppose.

[Lar4t9r]

Ford manuals say remove glove box, Remove upper retaining screw then use long 1/4 extension and remove lower screw. Pull the unit out by the wires. Plug the wires onto the new unit and the put in upper screw then lower.I just found the specs. Page 36-10-02 says 8.0 Amps max for F-Series for the motor @ 12.8 Volts. So back to the math.
102 Watts max
1/2 speed .8 ohms and the resistor must be 54.4 watts
1/4 speed 1.2 ohms and the resistor must be 76.8 watts
Round the resistor wattage rating to the next higher standard value. So a 76.8 should need a 100W ceramic sand resistor.

If you can get them with those wattage ratings you can put them in parallel that requires more math but can get you what you need,

Say you can only buy 10 Watt resistors that means 8 resistors in parallel. Ouch the required area to mount them gets big.

Dragon:
Thanks for the math, I'm going see about gathering resistors. Meanwhile, Fordman hooked me up with a working resistor and a blower assembly (paid him friday received today). bench tested and hope to get it in the ol' 69 tonight or tomorrow after work.

I just about have my instrument cluster restored so I can get that back in and then see if I can get all my gauges and lights to operate. Right now all I have is headlights and front passenger parking light. I've been studying the wiring diagrams on the site, so wish me luck. I'm sure I'll have more questions. Thanks all.

[fordman]

that was fast i mailed in friday afternoon.

[FORDification]

i dont think you can plug them in backwards on the ressitor. i think its a three pronged plug. unless you missed the top prong and put the plug on upside down. i guess that could be called backwards i suppose.

It's only a three-pronged plug if you have a two-speed setup. Not all trucks were equipped like that though.


Click to enlarge

[kaptnkaos]

Yeah...
mIne is definuitley a 2 speed set up...
I am 100% possitive that I hooked the plug back, 'cause I had to pul the box down to hook it back up...
When I was installing it, I hooked the wire up and it got pulled off wrestlin' it into place..
I had to drop it down a little and hook it back up...
that's when havin' a buddy ta help really comes in handy...

KaptnKA S

[fordman]

now thats something new i didnt know about. what determined if the truck had only a one speed fan resistor?