I haven't measured the voltage at the blower yet, but i'm sure there is a little drop there. Anytime you run that much wiring your going to lose some of the voltage, that is just the nature of DC. The motor may not last as long with direct battery voltage, but you can always get one from the junkyard as needed. It will probably take several small modifications working toghether to make a significant increase in air output on these trucks. Since the blower is fairly close to the battery, I don't think it is very difficult to add a relay. Because the factory connection at the blower has blade terminals in it, you won't even have to modify any wiring.

 

I have the same problem. All of my Bronco's 90, 91, and 93 have the same four speed fan and for the air conditioning none blow fast enough on high. However, my 95 F150 has a fan that has a much higher cfm than any of the others. In fact when it's on the #3 setting, one lower than the highest, it equals the output of all the others when they are on #4, the highest setting. It is very noticable, it actually blows so hard on high it's noisy from the wind it's putting out and almost annoying. It's so much that on a hot day after just a couple of miles you've got to turn it down. The both have the same part number for the motor so it's got to be the blower fan itself. Does anyone know if there's a difference in the plastic fan? I really don't want to remove from the F150 just to look but I don't know what else could cause such a difference.

 

My 84 had a volcanic heater and Ice-age inducing A/C. Was restoring the truck and figured the blower should be as tired as the rest of it. Boy was I wrong. Replacement blowers (tried two sources) did not cut the mustard, probably about like you all are seeing now. Of course by the time I figured this out the original was long gone.

If you can find an older Bronco, I'll bet it has a stronger blower. The parts book replacement listed the same part for single cab pickup and Bronco, so it must have been only the factory installed one that rocked.

Cheers,
- Jeff

 

I'm certain the blower motor in my 87 F250, 90 Bronco, or 91 Bronco have never been changed and they all blow the same. My 93 Bronco I did change the blower motor only because the original made a squealing noise. But the new one and the old one blew the same speed. My 95 F150 on the other hand blows like a hurricane.

 

This be a mediocre suggestion but also check the housing and all the plastic tunneling that the air flow in. If it has holes they can leak the air out or if it has that flexible plastic tubing such as these

The wrinkling of the plastic can disrupt the air flow and slow it down. I have seen a bit of this style tubing in older vehicles but only for tight corners or things like that. It would be worth a look.