Blower motor problem

Tiny
NATHAN-R-HENRY
  • MEMBER
  • 1996 CHRYSLER CIRRUS
  • 166,000 MILES
When it is cold/freezing outside my blower motor for my heat does not work. I changed out the antifreeze in the fall and have not done anything to effect it other wise. Any idea's on what it might be? Thx in advance
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Wednesday, December 21st, 2011 AT 12:24 PM

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Tiny
DRCRANKNWRENCH
  • EXPERT
If the blower motor is not blowing air at all, I am going to send you the flow chart for diagnosing an inoperative blower motor.
It is hard to say why the temperature is affecting it working other than it might be a fault, this would only apply to the automiatic air temperature controlled A/C system, in the temperature sensor for the automated temperature control. There are a few sensors that could be at fault. If that is the case a trouble code check would identify the electronic components at fault. So, get the trouble codes pulled and they will have a brief descritpion of any issues. The malfuntion light does not have to come on the have a trouble code come up. Any Advance Auto or Auto Zone will pull codes for free. If you get a code, that is the issue causing the problem, otherwise follow the flow chart which will include trouble code related issues.
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Wednesday, December 21st, 2011 AT 12:52 PM
Tiny
NATHAN-R-HENRY
  • MEMBER
Ok I will pull the codes as I have a code reader and will post back later on what they say. Thx for the assistance.
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Wednesday, December 21st, 2011 AT 1:19 PM
Tiny
DRCRANKNWRENCH
  • EXPERT
Your very welcome. I will keep an eye out for your replay and get back to you ASAP. You may also go through the diagnostic flow chart to eliminate other possibilities or follow leads you might get from the trouble codes. Read the chart before you get the codes pulled as it may refer to a code that comes up when you get them pulled. You will need to know this in order to follow the chart correctly.
Good luck and I will keep an eye out for your response.
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Wednesday, December 21st, 2011 AT 1:53 PM
Tiny
NATHAN-R-HENRY
  • MEMBER
Ok I figured it out but dont what would cause it. The fuse has to be pulled out then re-inserted then the fan works. It works half the time, but the other half the fuse has to be taken out and put back in to get it going. Thx
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Friday, December 23rd, 2011 AT 12:53 PM
Tiny
DRCRANKNWRENCH
  • EXPERT
Your are very welcome. I am perplexed by that, very odd. That is behaving as if there is a bad capacitor in the circuit that has a, "hot at all times" fuse /power source. But there are 3 fuses for the A/C system circuit. Number 1 is a 30Amp fuse and that is for the blower motor. Fuse numbers 9 and 19 are 10 and 40 Amps and run the relays and the cooling fans.
When the fan is on full or position 4 it runs straight from the fuse to the motor to the Switch which runs to ground. There is a thermal limiter but it does not appear to have any affect in this position. In the other positions there is a resistor that has a longer path, the lower the setting. These run from power to motor to the Thermal Limiter which would act like an off switch if the circuit gets too hot, then on to the resistor and then to the switch and then to ground. I am giving you the wiring diagram as you should check the grounds for the control panel that the switch uses and any others that might affect the circuit.
If all the grounds are free of corrosion and have a good fit, then I think the blower motor resistor, which contains the thermal limiter switch, needs to be replaced. The switch is normally closed but may be sticking open and resets to closed when the fuse removes power to it. You could check this with a multi-meter by testing for voltage beyond the resitor but before the switch when the car is off and then in the ON or RUN position. If voltage is not present, try testing the fan in the full position or 4. This eliminates the resitor and thus the thermal limiter. If it has voltage then the resistor is probably bad. Even though the circuit wires pass through the resistor assembly, in the full blower switch position the resitor circuit is bypassed and just runs by the resitor and thermal switch and essentially just goes straight to ground. If there is voltage in position 4 and the fan does not work, there may be a fault in the control panel or the ground may need to be cleaned and checked.
I cannot think of another scenario that would cause this behavior.
Let me know how it goes or if you have any questions.
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Friday, December 23rd, 2011 AT 3:19 PM
Tiny
NATHAN-R-HENRY
  • MEMBER
I wanted to let you know that I bent the actual fuse prongs which gave it a better contact and solved problem. Thx for the help
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Wednesday, January 4th, 2012 AT 4:47 PM
Tiny
DRCRANKNWRENCH
  • EXPERT
That is great news. Be really careful with that fuse from now on because it is such a high amperage. Somebody probably put it in and missed one of the connectors and spread it. Not a good thing as it is weaker now and also has higher resitance at the bend point, if it is bad, so take a look at it with a flashlight. You can replace blades but sometimes you have to get a new board. It is not a common fuse to have to replace unless you have a problem, so just be careful.
Thanks for letting me know how it turned out as I always wonder and I REALLY appreciate the thanks as that is what makes this job worth it.

Take Care

Dr. C
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Friday, January 6th, 2012 AT 1:22 AM

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