Not sure what's making the fuse pop here. The fan knob off/low/high runs fine. Good blower and heat works. When you pull it out to defrost it pops the fuse. Thinks it's in the switch? Or an air door is hung up and that draws the amps and pops it? Where would you guys start? Thanks.
check fuze size. it maybe too small. probably calls for a 15 amp or 20 amp check your manual. you can always try a circuit breaker that pops right in place of the fuse. just make sure you don't go with A higher amperage circuit breaker or fuse than what the specs call for.
bruh i dont think your truck likes you, shes giving you all kinds of problems! haha yeah check all your hoses somethings causing it to use way more power than youre supposed to. by the way if you havent already theres an AWESOME 57-60 f-100 group on facebook, join! theyd love to have ya and you wont regret it. lots of parts/nice people/helpful info on there.
Thanks for the heads up on te FB post. The truck is very solid and reliable. I'm just fixing small things that the PO " lived with". Most of which is new shocks, plugs... You know. Stuff actually needs replacing every 60 years!!!!
I would trace the wiring to the switch and motor. The defrost control should have nothing to do with the switch or motor as it is all mechanical to the best of my recollection. Look for bare wire that may be in contact with the vent linkage. Look for any foreign substance that may be obstructing the fan. It is also possible that the motor is worn to the point it pops a fuse from that tiny extra load when the defrost is open. As with anything electrical...check all the grounds.
Is it possible it could be the switch is bad and shorting inside it? The fan blows strong and all. I will look at the doors and make sure they operate before I go too much further. Fan runs as it should on low and high as well. It spits great heat. It just can't do both. I will check the fuse amp that's in it too.
I don't know how it is on fords, but on early-mid 60s chevy trucks, the blower switch and defrost cable are one part, the defrost cable slides thru the blower switch. It could easily be something in the switch shorting out. I would take the switch out and look at it very closely, see if there are signs of arcing, broken insulation, etc.
I would follow F ones advise. It's a simple system & plenty of room to work on it. Sounds like a bare wire laying on the defroster cable or defroster door lever.
Take a look at LMCTruck.com site page 48 of Ford catalogue. Shows regular multi-speed switch (#7). 67 switch has cable thru, but not 57-60. Does show cables to operate flaps. You say fan operates low and hi, so cable must not be opening flap OR airflow in defroster hose is plugged somehow. Be sure and buy from them, cause I can't figure out how to get the page off after copy actually worked. They have always treated me well. What are you pulling out (first post) when the fuse pops?
Fan works on LOW and High just fine. Heat is awesome. When you pull the knob for defrost, it pops the fuse. I can't hear it arc or snap anywhere. I'll look closer when I get off this week.
So, pull the defrost knob when the truck is not running, to see if the cable slides and moves the defrost lever. (which is likely to be sticking out of the heater box/plenum) We are talking about a separate defrost knob on this year truck, right?
hey it could be worse.. when I turned on my heater for the first time it blew sand all over me and my dad, and then wouldn't shut off! I had to disconnect it completely rom the truck while my dad was rubbing sand out of his eyes, it was pretty hilarious. also, just your standard vacuum cleaner hoses will work for the ducts and stuff going to the defroster right? it probably will I was just gonna make sure before I run and get some.
This truck (1960) is the knob for fan and you pull it for defrost. Maybe that's not correct for this truck but that's what it's got.
Like #8 in LMC catalogue page above? I'll ask again, does the cable move the flap when you pull the knob?
Apparently you have the standard heater, not the Magic air. The most likely cause is a short in the switch when you pull it out for defrost. Replace it.
Does your dash have a hole for the defrost cable like in LMC catalogue pic? If so, what is in that hole now? Could you get the proper switch and separate defrost cable and solve several problems?
My wife took this pic. Hmmmm. I'm too busy working extremely long days and some travel in between. I'll get up under the dash but I spied this. We've only had the truck a month. So I apologize for not having much history on it. The mystery hole in dash.
That would be wires to motor from switch. Cable looks like 18578 0n end of dotted line from same number switch. It slips on 19387 which operates 19397 defrost flap.
I googled 1960 ford pickup dash images and could not tell for sure. LMC shows them separate for that year. The Ford Truck Enthusiast forum shows two types of heaters and their switches. If your heater looks like the one in this illustration, the one you have is probably right (but shorting out inside). Check out that forum. It might be your choice.