Hello Again..I've installed two (2) heater blower resistors and for some reason, it keeps breaking..Probably about 2-3 weeks apart from installing each..When I install it, it works fine for a while. Then, it just blows on high..Thanks..

 

What brand of resistor block?

Is it blowing the Blower fuse?
If not then I would say the Brand is the issue, not a vehicle issue

The resistor block is the GROUND for the blower motor, each resistor lowers the ground connection so reduces blower speed
This causes the resistors to heat up, which is why they are located in side the blower housing so the blower cools them off when its on
If cheap resistors are used then they won't last very long


EDIT
Just re-read your post

HIGH by-passes resistor block, its a direct ground, but there is a thermal limiter which could be the problem, if you loose all speeds, not just high

What YEAR is the Ranger?

 

Hey RonD..Thanks for the reply..It's an AutoZone Duralast..No, it doesn't blow the fuse and it's a '91 XLT 3.0....It's still working on high as it always does..Thanks..!

 

1991 doesn't use the thermal limiter on HIGH setting just on the lower speeds, diagram below

The Speed control switch by passes the resistor block completely when on HIGH

It could be the blower motor itself has reached end-of-life, but I would expect it to blow the fuse on HIGH

The Motorcraft resistor block might be the way to go, I would first pull out the Duralast block and have a look at what "blew" and if you still have the previous one, look at it as well

 

Hey RonD..Thanks for the PDF..Yeah, I think I'll try the Motorcraft resistor and see if it blows..If it does, then I know there's other issues going on..Thanks..!

 

Have to ask, You did re-install the new resistor block back into the heater duct work of your truck, The resistor needs air blowing over it to keep from overheating and burning up.

 

Hello..Thanks for your reply..I don't quite understand exactly what you mean..I installed it as it was before..That being said,there is a port at the bottom of the blower motor case that seems to be looking for a hose to be hooked to it..It was always missing but I never had issues before until the resistor went out the first time...Do you know what this port goes to..?..Thanks..

 

The hose goes between the plastic housing and blower motor's metal case, its for air flow in the brush area of the electric motor, the metal case isn't vented because then the motor would get "dirty air" from the engine bay

 

Hey RonD..Thanks..Is there a photo link somewhere to show how this hose is implemented..?..I see where it connects to the blower case, but can't see where it ends up.......

 

On the bottom side of the blower motors metal case, feel the under side of the motor, you should feel the hole, its just a squeeze fit hose
It works fine without it, but can make the electrical contacts inside the motor get dirty before their time

 

Ok Thanks.. So both ends of the hose connects to the blower motor case..?..

 

No, one end connects to the plastic housing

Try watching videos for Ranger blower motor replacement
It varies by year so find one for your year

 

Ok..Thanks RonD..Have another question ( different one ), but starting another thread as your answers may help someone else..