how do you get to the blower motor on a 78 F250 with factory AC? is it behind the glovebox? everything under the hood is riveted together. my blower motor is squealing like it's got a spun bearing.

 

Try searching this forum on 'heater core' or 'blower motor'.

 

I dont know about a 78, but my 76 w/o ac was a pain in the butt ! I had to remove the whole heater assembly to get to it, all the duct stuff under the dash had to come out.

 

The article in the tech section that covers heater core replacement on these trucks will cover all the steps you need to replace the blower motor too. It's a long process and a major pain. I'd definitely recommend replacing the heater core while you're at it. It'll cost $30 and you won't have to worry about tearing it apart again for quite a while.

https://www.ford-trucks.com/article/...es_Trucks.html

 

I had to put a new one in my 77 with factory AC and it’s a pain. The best advice I can give you is to get a copy of the factory shop manual and follow the directions. It gives great step by step instructions and good pictures. To give you an idea of what you’re facing, it took my three hours to take everything off just to be able to get to the blower motor. Make sure and label everything or as I did, put everything in its own Ziploc bag and then label it. Also, be prepared to get cut up a lot from the evaporator. Ford didn't leave very much room to get around it. Unless you don’t mind losing all of your refrigerant, then you can disconnect it and the job would be a much easier. Good luck!!!

 

My Haynes (or is it a Chilton - it's out in the garage, I forget which it is) says go ahead and work on heater-only vehicles, no problem, but if you have A/C it's beyond the means of most home mechanics, so they don't even explain the process and recommend getting it worked on by a pro.

 

You need to throw that Haynes manual away. It is so wrong about the abilities needed to do this job. Basic hand tools, a couple hours labor and a limber back.

 

Replaced the blower on my 76 w/o ac thank god but i never had any problems with the ducted work since i have only defrost and floor which by the way only blows to the driver side footwell the passager's get to bundle up.

 

If your ac set up is the same as my 74 highboy. This is what I did to replace my blower motor. Where the box sticks out into the engine compartment on the passenger side there is a large flat cover that is rivited in place.The blower motor is just behind that cover. I cut the rivits of and removed the cover. It has been several years so I don't remember how the blower motor is attached inside the box. I do remember that it is designed to come out from the inside. I used a small cut off wheel on a die grinder to cut up frame work that holds the blower motor and removed the old motor. The new motor comes with the same frame work attached to it. You are not destroying anything that you need. I then took the fan off the old motor and put it on the new one. I then bolted the new motor in place from the outside. Doing it this way your motor is in the same plce as the origional. It may may stick out 1/8 of an inch but the cover will still fit. You can compensate for the 1/8 by where you put the fan on the shaft of the motor. I used crimp connectors for the wires. You may also want to use some shrink insulation. I then used some pop rivits to replace the cover. Unless you look real close you cant even tell I ever opened it up. It worked for me.I hpoe the info helps.

 

Just changed the core and motor in my 76 the other day, but it was w/o ac and I had it done in about an hour. I have the same manual and it says not to mess with it if it has factory AC and I figure it is because they don't want you messing with freon.

 

ivanribic has steered you straight here with the core replacement while at it .
I replaced the one in my '78 and the heater did have to come out on mine as well . Pretty tight fit too for the heater in mine . The '78 did come with 2 different heaters though and I've never done one of the others .

When replacing the core I shortened the stubs and reflared a new bubble on them so they just reached far enough through the firewall to get the hoses on which made the reinstulation much easier .

 

ac is totaly different from no ac. no ac isnt bad to replace dont know about the ac model personally but the service manuals say to access it from the dash side of the housing check ebay for a set of shop manuals i got mine for 25 plus shipping and since they are a ford original service manual they have all the information for e,f,u,p,b,l,w, series all the way up to an w9000

 

i thought about going at it from the engine compartment by drilling outthe rivits as was described. sounds like i better set aside a weekend to do this job the way these projects seems to go. sheesh why did they make it so difficult? on a lighter note, my buddy's '95 Z71 has a nightmare blower motor that failed much earlier in the life of his truck than mine so that make me feel a little better.

maybe i'll wait for it to lock up. it's started snowing again anyway, i need the truck to plow.

 

The only problem I see with going in through the engine compartment is that the blower motor mounting screws attach from the other side. There would be no way to get to them. If by chance you did get them out, the blower motor has a flange around it that wouldn't fit through the squirrel cage hole. When you take the cover off from the engine compartment, the onyl thing you really gain access to it the air path way. All of the internal guts are seperated in there own compartment. It's not easy to go through the dash but it's the best way and yes by all means replace the heater core too, it has to come out anyway! Overall, it wasn't one of Ford's better designs!!!

 

go to the article in the tech section if you try it from the engine compartment you WILL srcew up the heater plenum and be really mad at yourself for trying to take a dead ended shortcut believe me been there done that