I recently installed a new heater core and got my AC up and going, but for the life of me I cannot figure out why my fan speed selector won't turn on my fan, I replaced the resistor, and checked the vacuum plate in the dash, all is in tact. When I connect the blower motor to power it will blow, but only at a minimal speed, please help, ac sucks when it can't reach you! 😂 Thank you for all the advice

 

Sounds like a bad connection or a bad blower. I put mine on a relay, blows a lot better although it probably still needs replacement eventually

 

I just had trouble with my blower motor recently as well. Does the fan work on HI? If not then you need to replace your blower motor. When on HI the 12V completely bypasses the resistors.

You might also consider disassembling your dash. The fan speed switch and wiring receptacle were toast in my truck.

Here's a link to the thread on my blower motor repair.

https://www.ford-trucks.com/forums/1...otor-help.html

 

No it wouldn't work at all, no matter where the switch was, is it ran by the same vacuum as the other controls?

 

Did the new Blower fix the problem? You need to up date the other thread.

My fan had been squeeking and squaking for a while when I turned it on. Finally replaced it (after we blew the heater core
late one night out in the middle of BFE 150 miles from home )
Replaced the Core along with a new Blower from Autozoo. They were both about $25 ea.

Didn`t realize how slow the old blower was till I turned on the new one.
Iam thinking that an old tired worn out motor with Brushes that are shot along with dry bearings
is putting a load on the switches, resitors etc... and that is the root cause of many electrical problems.
heating up the componets long enough till they finally fail.

Charlie

 

Okay, I will try replacing the blower motor, thanks for the help!

 

on my 88 it was a bad wire coming off the fuse block. i ended up having to bypass the AC/heat fuse in the fuse block and add a separate 30 amp fuse to that line.

 

Sorry for the delay, things have been crazy recently.

Yes, the new blower motor fixed my problem. I got lucky and the switch and receptacle didn't fry again trying to turn the bad blower motor.

I also found that the new blower motor worked much better than the old one. Don't forget that after installing the new blower motor you may only get air from your defrost vents. Especially if the truck had been sitting for a day or two. Starting the truck will run the vacuum pump allowing you to operate the air doors. My vacuum reservoir must be shot.

 

With the factory wiring there is significant voltage drop to the blower motor (2.85v on my truck). If you want more CFM from it and to improve the electrical system overall, use a relay for the blower motor. Voltage drop went down to .31v after putting it on a relay. Air flow improved somewhat, but when there's low output every little bit helps. Also reduced overall voltage drop in the cab. The blower motor is the highest electrical load on the vehicle.

https://www.ford-trucks.com/forums/1...tor-relay.html

 

I installed a new blower motor today, it increased the air that I was getting, but the switch doesn't work still, I will check the fuses tomorrow and update from there, thank you guys! On a side note I bought new led headlights super excited for them I'll post a picture when I install them

 

Regarding headlights... Most LED headlights are low quality junk. Even the good ones are not likely to give you a better beam pattern and overall illumination than a quality H4 reflector and bulb along with appropriate wiring. Poor light distribution and cutoff are common even on the more expensive units. Much worse, there is a huge safety issue of blinding other drivers with the poor cutoff and pattern. Glare is typically horrible.

Performance will not be nearly as good with any of the available LED as it will with a quality H4 setup. Cibie is generally regarded as the best. Bosch is also good, Hella has some flaws in the reflector design but is passable and a safe upgrade over sealed beams. Also avoid DOT compliant reflectors, go with ECE. DOT mandates about 20% of the light output be thrown up into the trees and blinding oncoming drivers. ECE has a defined cutoff and puts more light where you need it. Philips or Osram for quality bulbs. Relays and minimum 14ga wire. Return the LED headlights and get a proper headlight setup that is functional and safe.

Personally I went with Cibie ECE reflectors, a Bussman RTMR for fuses and relays, Philips Xtremevision bulbs, wiring I believe is 6ga to the RTMR, 12ga within that and to the first headlight then 14ga to the second. Could not be happier, after doing the truck I did the same upgrade on two of my motorcycles.