Is my HVAC fan bad or the fan switch?

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gimme789

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Hello, My 2004 TJ Rubicon 4.0L fan only works on the highest setting (full blast). I thought it must be the switch, so I got one and (of course) it was not the switch. Can the fan be the issue ? The connector looks good. Part 2) how difficult is it to replace the fan itself ? ( replacing the switch weasn't bad at all) Thanks In Advance !!!! Tom
 
It's most likely the resistor. A search for blower resistor should give you all the information you need.
 
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gimme789 said:
Hello, My 2004 TJ Rubicon 4.0L fan only works on the highest setting (full blast). I thought it must be the switch, so I got one and (of course) it was not the switch. Can the fan be the issue ? The connector looks good. Part 2) how difficult is it to replace the fan itself ? ( replacing the switch weasn't bad at all) Thanks In Advance !!!! Tom
Click to expand...

Most likely it is the blower motor resistor when the fan only runs on high. Inexpensive part that is easy to replace.

https://wranglertjforum.com/threads/heater-only-works-on-high.28364/#post-456587
 
gimme789 said:
Where is the resistor located? Is it tough to get to ? THANKS !
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It is in the heater box just behind the glove box and it is a 10 minute job.

Best way to see how it is done would be U-tube, just search for Wrangler TJ blower motor resistor.
 
WDE said:
You might as well replace the blower motor while you're at it. As they age, they start drawing more and more current, causing blown resistors and melted connections on the switch. It's cheap and easy to do and cures the problem, not just the symptoms.
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Will do .... thanks for the advice ... was kind of wondering why resistor(s) would go bad ...
 
OK, what is the trick to disconnecting the blower electrical connector ? I moved the red slider, still on tight... I'm, afraid I will break the connector ... do you have to release something else to get it to release ? thanks
 
The re
gimme789 said:
OK, what is the trick to disconnecting the blower electrical connector ? I moved the red slider, still on tight... I'm, afraid I will break the connector ... do you have to release something else to get it to release ? thanks
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The red slider is just an assurance device. Once you Pull it back you still need to push the release tab to disconnect. With a blown resistor you may have melted the connector also making it hard to come apart. If the connector is melted then replace the blower motor as well. Along with the pigtail of course
 
WDE said:
You might as well replace the blower motor while you're at it. As they age, they start drawing more and more current, causing blown resistors and melted connections on the switch. It's cheap and easy to do and cures the problem, not just the symptoms.
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agreed. The motor brushes become worn down and contact becomes weaker resulting in higher amperage draw. Higher amperage draw burns up the resistor. I turn wrench’s for a living and see it a lot. I always call a motor and resistor.
 
Stuckless said:
agreed. The motor brushes become worn down and contact becomes weaker resulting in higher amperage draw. Higher amperage draw burns up the resistor. I turn wrench’s for a living and see it a lot. I always call a motor and resistor.
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Worn brushes don't cause excessive current draw from the motor, it's the motor's windings starting to short to each other as the shellac insulation on the winding wire starts breaking down.
 
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WDE said:
You might as well replace the blower motor while you're at it. As they age, they start drawing more and more current, causing blown resistors and melted connections on the switch. It's cheap and easy to do and cures the problem, not just the symptoms.
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Mine kept burning up the fan speed switch. I finally replaced the blower motor, and burnt wiring, and mine has been fine since.
 
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Jerry Bransford said:
Worn brushes don't cause excessive current draw from the motor, it's the motor's windings starting to short to each other as the shellac insulation on the winding wire starts breaking down.
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I agree with that as well. But some motors have a rubber air vent that feeds back to the brushes to help cool them. You take that off and look at the brushes and the armature you can see the armature is carbon tracked which is cause by bad brush contact. Contacts always get hung up in Their track as they wear down and require higher draw to jump the gap. Or that’s my theory anyways I have know to be wrong a lot of times lol
 
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