Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Troubleshooting/Problems Discussion (http://www.jeepgarage.org/f77/)
-   -   Keeping Blowing Blower Motor Resistor (http://www.jeepgarage.org/f77/keeping-blowing-blower-motor-resistor-42742.html)

GratefulDeadWK 05-30-2012 03:30 PM

Keeping Blowing Blower Motor Resistor
 
Just replaced my blower motor resistor and within a few hours it stopped working again, I.e only on high. Is there a fan control resistor as well what seems to be causing this issue, any ideas?

Rocky31186 05-30-2012 03:45 PM

Re: Keeping Blowing Blower Motor Resistor
 
What brand resistor did you use? You could have possibly got a bad one.

GratefulDeadWK 05-30-2012 03:58 PM

Re: Keeping Blowing Blower Motor Resistor
 
I got a Standard Motor Products one, It did work for a little bit on all the settings then after work I try it and only works on high again. I will say that the lowest setting was weak but maybye i just have not had my full range of speed in a while...

Frango100 05-30-2012 08:24 PM

Re: Keeping Blowing Blower Motor Resistor
 
Can be that the blower motor is getting bad, drawing too much current and frying the resistor in no time.

GratefulDeadWK 05-31-2012 07:39 AM

Re: Keeping Blowing Blower Motor Resistor
 
Hi y'all, yes, spoke to a buddy who is a automotive engineer and he said the same thing. I know there prob 1001 threads but how involved is the motor to replace? It looks to be right behind the glove box.

Rocky31186 05-31-2012 11:12 PM

Re: Keeping Blowing Blower Motor Resistor
 
I personally think if the blower motor were going bad / pulling voltage it would blow the fuse before going to the resistor.

If it were my car I was warranty out the resistor and see if it happens again.

The resistor controls the voltage going to the blower motor.

GratefulDeadWK 06-01-2012 09:24 AM

Re: Keeping Blowing Blower Motor Resistor
 
No warranty and if you say its the fuse wouldn't the blower not work at all? It still works on high

Rocky31186 06-01-2012 10:43 AM

Re: Keeping Blowing Blower Motor Resistor
 
Im not saying Its the fuse... Im saying that if the blower motor was bad it would blow a fuse.. not back feed to its power controlling device of the resistor.

2005JGC 06-01-2012 02:39 PM

Re: Keeping Blowing Blower Motor Resistor
 
Not so true Rocky, I have found some circuits to be more protected against excessively high current draws... I have seen fuses melt down, not blow (oem fuses, not harbor freight junk) when a circuit is drawing right at or near a fuses current limit, at this point wires can be getting warm, pins can be heating up. Also Voltage is not what blows the fuse, as stated it is current or amperage. Voltage remains the same, amperage changes to changes in resistance.

It is not uncommon for a blower motor/fan to draw excessive current. which will melt down weak points (the fuse being one, but again as stated, fuses are not the end all).

Also there is no backfeeding happening, its a matter of electron flow, an electric motor depends on counter electron flow to limit current flow throught he device (when the magnetic fields colapse it induces reverse current) and when a fan is slowed due to any number of internal/external reasons your counter current flow is reduced allowing excessive current through the device... if you google a starter motor amp trace you will see as the starter is first engaged you can hit upwards of 300 amps but if it stayed there you would have a fire, once speeds up amperage is reduced to the neighborhood of 70-90... furthermore if you ever take a fan and stop it, I promise you you will start to see smoke ;) . When you have a resistor and crank the amperage up the resistor is going to be the hot point in the circuit.

I agree with frank, I would suggest you warranty the resistor and replace your blower motor, then let us know how that goes.

GratefulDeadWK 06-01-2012 02:48 PM

Re: Keeping Blowing Blower Motor Resistor
 
Quote:

Originally Posted by 2005JGC (Post 637568)
Not so true Rocky, I have found some circuits to be more protected against excessively high current draws... I have seen fuses melt down, not blow (oem fuses, not harbor freight junk) when a circuit is drawing right at or near a fuses current limit, at this point wires can be getting warm, pins can be heating up. Also Voltage is not what blows the fuse, as stated it is current or amperage. Voltage remains the same, amperage changes to changes in resistance.

It is not uncommon for a blower motor/fan to draw excessive current. which will melt down weak points (the fuse being one, but again as stated, fuses are not the end all).

Also there is no backfeeding happening, its a matter of electron flow, an electric motor depends on counter electron flow to limit current flow throught he device (when the magnetic fields colapse it induces reverse current) and when a fan is slowed due to any number of internal/external reasons your counter current flow is reduced allowing excessive current through the device... if you google a starter motor amp trace you will see as the starter is first engaged you can hit upwards of 300 amps but if it stayed there you would have a fire, once speeds up amperage is reduced to the neighborhood of 70-90... furthermore if you ever take a fan and stop it, I promise you you will start to see smoke ;) . When you have a resistor and crank the amperage up the resistor is going to be the hot point in the circuit.

I agree with frank, I would suggest you warranty the resistor and replace your blower motor, then let us know how that goes.

I'm very very impressed with this response! Anyways this is keeping me on me and my friends theory here on the blower motor. As far as warranty goes, I'll pony up another $13 for a fresh resistor post blower motor replacement.. Its on my list to do, since its summer I don't use the HVAC that much as I'm always driving with the windows down and for heat I bring a sweatshirt. I will keep you posted. Thanks for the help.

guitarguy2186 06-01-2012 03:51 PM

Re: Keeping Blowing Blower Motor Resistor
 
change the wiring harness that goes to the resistor they sell them at the dealer for 15$. Mine was doing the same thing and they wanted me to change the motor, i changed the harness and it hasnt done it since. I dont know if youll be lucky like i was but its worth a try since the harness is so cheap

2005JGC 06-01-2012 05:03 PM

Re: Keeping Blowing Blower Motor Resistor
 
Yes, the harness is VERY common on WJ's less common (but still happens) on WK's but still inspect for a melted connector at the resistor.


All times are GMT -5. The time now is 11:15 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community