Heater gremlin...
If i had even a test light i would be crawlin all over that thing right now... sadly not much i can do.
I think when i put the blower motor to the grn/yel it was too much draw for the circuit, but it didnt blow any fuses... so wtf did i do there? You really dont want to know what the wiring looks like under the hood... not pretty. I really need to get a new harness and start from scratch, which is the plan when i tear it down to restor it, but thats a ways out so just trying to keep the thing together without burnin down.
Can you see the pictures i linked now?
Low-1
med low 2.5
med high 3
high 6
puttin the motor straight to the battery-10
but even if the resistor was bad, i should have power on high...
Ford Trucks for Ford Truck Enthusiasts
Pictures are working now!
The picture that OldStyle uploaded is good for showing how the resistor works. There are 4 different input voltage locations in your case, and 1 output. Low goes through 3 resistors, med low goes through 2, med high goes through 1, and high doesn't go through any. When you go to a higher setting on the fan, you DEcrease the number of resistors, and therefore resistance, resulting in an INcrease in voltage (because the resistors are in series). Current (amps) stays the same. V x A = Watts or Power
"High" travels through no resistors, but must get to the final terminal with the BLK/YEL wire coming off it. Inside the resistor assembly, there is a connection between the High in and the output BLK/YEL terminal. Maybe this is bad.
Do you have a multimeter? If so, check the resistance between those two points.
The reason it works so good when connected to the battery is the current available. When hooked to the proper terminal, you have 12 V (for simplicty's sake) and a max of 30 A, which is what the fuse is. 12 V * 30 A = 360 Watts. When you connect it to the battery, again you have 12 V but now you have 400 Amps (for simplicity's sake again, I don't know what your battery is rated at). 12 V * 400 A = 4800 Watts. That's why your blower works so much better connected straight to battery power
Pictures are working now!
The picture that OldStyle uploaded is good for showing how the resistor works. There are 4 different input voltage locations in your case, and 1 output. Low goes through 3 resistors, med low goes through 2, med high goes through 1, and high doesn't go through any. When you go to a higher setting on the fan, you DEcrease the number of resistors, and therefore resistance, resulting in an INcrease in voltage (because the resistors are in series). Current (amps) stays the same. V x A = Watts or Power
"High" travels through no resistors, but must get to the final terminal with the BLK/YEL wire coming off it. Inside the resistor assembly, there is a connection between the High in and the output BLK/YEL terminal. Maybe this is bad.
Do you have a multimeter? If so, check the resistance between those two points.
The reason it works so good when connected to the battery is the current available. When hooked to the proper terminal, you have 12 V (for simplicty's sake) and a max of 30 A, which is what the fuse is. 12 V * 30 A = 360 Watts. When you connect it to the battery, again you have 12 V but now you have 400 Amps (for simplicity's sake again, I don't know what your battery is rated at). 12 V * 400 A = 4800 Watts. That's why your blower works so much better connected straight to battery power
The connection in the resistor youre talking about being bad, now that i can understand. Sadly as i said earlier, i dont even have a test light let alone a multimeter. As far as the motor... isnt it only going to draw what its going to draw basically? The fuse doesnt have anything to do with how much it actually draws, just makes sure it doesnt draw more than what the circuit can handle. Otherwise, blower motor + 2000 amps, lol no wonder it worked so well. On the other hand, i need to fix my dome light and stereo as well as the heater now, at least i know where to start with the heater, but im lost on the stereo and dome light. There were no burnt fuses. Did i somehow cook my ignition switch?
As far as the radio. There is a 3 prong wire under the dash that the glove box light plugs into. I had the radio batt. plugged in there. I moved it to the other accessory that is on the drivers side that i run my tach. off of. So radio fixed.
Dome light... im still lost on where its burnt out. Im sure that the blower motor overloaded the circuit, but i cant find a fuse or fuseable link to replace. Any help here would be appreciated.
I want to thank you guys for all your help in getting to the bottom of this. Btw when i manually jump the bad contact, the blower works like a champ. Air box and dash is dissassembled so i cant tell how much air its actually moving, but seems like it should be working good.
Is the light itself burned out? You may have blown the filament when you overloaded it.
Glad you got the radio figured out!
The radio, not fixed, forgot the plug i moved it to is key on only, and i need constant power, aka battery power.
So back to fixing the dome and stereo, i used the hot side of the dome light circuit to test the blower motor. Motor came on, overloaded the circuit. Now no dome light. I cant find a blown fuse tho.





