1989 bronco 302

Bought a bronco and the blower motor was bad. Replaced the blower motor as well as blower motor resistor. I turned the air on and it all worked great. All 4 settings worked great and the heat was hot and the ac was cold. Now I've suddenly lost the highest setting. Which throws me through a loop because it shouldn't have any problems since it doesn't pass through the resistor. If the resistor goes out I thought that is the only one that would work. But now I get to the route of the problem I'm trying to solve. My defrost works... decent. On the right hand side of the bronco the defrost works great. In the middle it works good and on the drivers side it works okay. Is this just normal since it all flows from passenger to driver side? Or is there a way to boost my output on the driver side? Even if it's after market or rigged up someone please help me out with an idea. I don't wanna use a portable heater or mount a 12v defroster. I'd rather overhaul the whole system. If anyone has any info or needs more info to help diagnose the problem let me know. I have checked the vent area and he cowl to see if it was clogged and got no unusual findings. I don't really know what else to check since the system seems to work, it's just soft on drivers side.

 

Yours is 10 years younger but when I pulled my evap case apart I found all sorts of leaks that caused somewhat of the same issue in my 79. The foam on the seals and doors was all rotted out, connections between plastic ducting loose, defrost vents warped and curled inward restricting flow, material ducting just disintegrated. I'm betting your issue is one or a combination of these. Also, AFTER I did my blower motor and hamster wheel I noticed there is a gasket of some sort that goes between the hamster wheel and the evap case. Mine is not present and that may have something to do with my mediocre air output. Good luck!

 

Thank you! I'll have to check that out soon. Did you have to tear your whole dash apart?

 

Since you do not have the highest setting , that position does not use the resistor at all, it feeds straight to the motor via the orange/black wire .So assuming no high setting I would look at that wire .When in the high position the orange/black ground via the switch .Now that it works on the other settings (using the diff. positions of the resistor) back to your black . , (We can assume your ground wire is good ) because the other positions use this). Try switching back n forth from med to high to see if high actually comes on. The only problem can be the # 1 orange/ black wire or the #2 highest setting on your switch (bad contact).On high try wiggling it see it comes on. On my 1985 the wires were burned back behind the switch causing it to intermediately work .Good luck and I hope this wasn't confusing

 

I didnt HAVE to pull it but it makes working on things so much easier. Especially if the truck is older and has **** wiring it is an opportunity to clean things up and make the electrical system a little more robust