Heater Issues

[LEB Ben]

Alright fellas...here's the deal, heater worked just fine yesterday morning. This morning I get out to the Bronco, and I'm getting really weak air flow. As I drive, and get higher in the rpm range, I get more and more air. Then if I come to a stop, so does the air. When I'm driving, and I throw it in neutral, I lose air as well. If it were a vacuum line, I figured I would lose air when I get on it, and I'm not. Blower motor going out? I didn't think that was fluctuate based on engine speed. So any tips, thoughts, advice, I would greatly appreciate it.

 

[LEB Paul]

How's the rest of the electrical working? Lights dimming at all? Only thing that comes to mind is maybe a dying alternator and you get more juice for the blower when the RPMs are up. Just throwin it out there..

 

[Mil1ion]

Clean off all your power connections at the starter relay and the ground wires as well.

Also try running direct 12 volts to the fan motor to verify it will run high speed

 

[LEB Ben]

The Alternator is less that 2 months old, and I dropped the coin for a Motorcraft unit this go round, so it better last longer than the cheap house brand alts I usually get. But I didn't notice any thing out of the ordinary from the electrical system...but the only thing I had on was the radio.

 

[LEB Ben]

Clean off all your power connections at the starter relay and the ground wires as well.

Also try running direct 12 volts to the fan motor to verify it will run high speed

Alright, thanks Dennis.

 

[TexasRho83]

What'd you find out Ben?

 

[LEB Ben]

What'd you find out Ben?

Dunno yet...I'm at work. I'll probably work on it this weekend.

 

[73F100Shortbed]

I would check into electrical stuff like suggested. Mine does sort of the same thing at idle and then the fan speed increases when I get it idling to around 1,000rpms. But I think it is just because of the alternator putting out more. I still have good air flow at idle, but I can hear the fan increase slightly when I raise the rpm. Maybe you have a corroded connector somewhere like Dennis said to clean and you aren't getting the right voltage. That's all I can think of right now. Maybe check the voltage of the alternator at idle vs. higher rpm. It will change obviously, but make sure it isn't too low at idle.

 

[TexasRho83]

Voltage regulator?

 

[Mil1ion]

The voltage regulator is what kicks in when more power is needed.

Next time check the speed of the wipers on low then high to see if they are affected as werll

 

[LEB Ben]

WTH...get outta work this afternoon and the heater is back 100%. Bad connection somewhere.

 

[Fellro]

#1 thing to do, verify the motor is working, as it sounds to me it isn't. If not, see if there is 12v to it. The air is coming out the right place correct? If so, then it is a matter that the fan motor isn't spinning up to speed, may well be that the motor is about shot. That actually is pretty common. The higher air flow is due to pressure from driving, and when you slow down, there is less pressure. I have had a few that the motor failed on that were like that.

 

[LEB Ben]

Thanks for the info Roger...does that still apply even though it worked correctly this afternoon? Assuming it only runs some of the time because it's on its way out?

 

[Fellro]

Sure can, the brushes may be sticking, or a bad spot on the armature. I have had some that work fine for a bit, then quit, then might come back. It could also be as simple as a bad connection.

 

[73F100Shortbed]

Sure can, the brushes may be sticking, or a bad spot on the armature. I have had some that work fine for a bit, then quit, then might come back. It could also be as simple as a bad connection.

Sometimes when they stop all together if you wack it with a hammer it will work just fine afterward too.

 

[Fellro]

for a while anyway... that would be either the brushes sticking, or a bushing problem typically. Do it too hard and things get broken....

 

[fatherdoug]

My old blower motor would not work until I crossed a rough set of railroad tracks on the way to work, which jarred the motor enough to start blowing. The motor would then stop, crossing the same set of tracks going home. New blower motor installed solved problem.

 

[Mil1ion]

Please Note:
The old adage of "use it or lose it" needs to be remembered for these old trucks

Brake system,Fuel system, electrical system are prime examples of this

Electrical parts corrode when not used.


To help you understand what I'm saying is

Many years ago in ther 50's and 60's this young man (Me) was known to quuickly turn the channel selector on our TV because the click click click click was cool.

When the TV repair man called one time because of a problem with the horizontal lines on it my Dad was quick to tell the man that his son probably damaged it from spinning the knob in what he deemed an irritating way.

The repairman quickly stated actually sir that is the best thing for the TV as it keeps the contacts on the switch clean from humanity/dust/corrosion.

There you have it. Use it or lose it

 

[LEB Ben]

Next question...I'm seeing on Bronco Graveyard that there is a difference in blower motors for an AC and non AC vehicle. The Bronco originally came equipped with A/C...but it is not stripped to the box, and the lines coming out are capped. So if I replace the blower...do I still opt for the A/C equipped motor or not? And does it really make a difference?

 

[Mil1ion]

Best to remove it first rather than assuming