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Unread 09-14-2012, 11:44 AM   #16
JBTJ
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2001 TJ Wrangler 
 
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Quote:
Originally Posted by BIRICON View Post
I have an 03 Rubicon. My fan won't work on the first 2 low settings but will work on 3 and 4 - the two higher settings. I assume this is also the same resistor/switch type of problem? Also what is the relay mod that may eliminate all of this?
Also, isn't there some 'special' tool needed to remove the black bezel over the center dash section?
Your resistor pack is probably out. The problem is with the design of the wiring of the HVAC system. As your blower motor wears it pulls more current, totally normal. JEEP for some reason and GOD only knows, decided it was a good idea to have a 10 amp switch control a 30 amp max motor, Dumb A's. The relay is installed between the switch and the resistor pack/blower motor. The relays are rated for 40 amps so they can handle the current the blower motor will ever put out without blowing the fuse. So what we have is the switch controls the relay and the relay controls the blower motor. It's basically a protection device for the switch and resistor pack. Once installed you will never have a problem again, unless the blower motor actually goes out. Or at least I haven't in the past 6 or so years. I was replacing resistor packs and speed switches every few months. Thank GOD no more. Some will say just replace the blower motor, which will fix the problem until that motor starts to wear and that under rated switch begins to fail again.

A phillips screwdriver and 3 screws to remove the front bezel, 4 more screws to remove the speed/mode switch console, is all that is necessary to gain access to do the mod. Need to be able to solder and have tops of 45 minutes to do it. Simple and very easy to do. I have done it now about 24 times.

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Unread 09-15-2012, 06:04 PM   #17
Gary2
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If unsure what part it is that is done try checking with an Ohm meter then their will be no more questions .
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Unread 09-17-2012, 04:39 AM   #18
Neil F.
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Quote:
Originally Posted by BIRICON View Post
I have an 03 Rubicon. My fan won't work on the first 2 low settings but will work on 3 and 4 - the two higher settings. I assume this is also the same resistor/switch type of problem? Also what is the relay mod that may eliminate all of this?
Also, isn't there some 'special' tool needed to remove the black bezel over the center dash section?

My lower speeds went one by one over time.
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Unread 09-17-2012, 01:20 PM   #19
tjneal1241
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What is the relay modification? I'm about to change the resistor and don't want to do it multiple times.
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Unread 09-17-2012, 01:22 PM   #20
JBTJ
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Originally Posted by tjneal1241 View Post
What is the relay modification? I'm about to change the resistor and don't want to do it multiple times.
Read post #16 basically sums it up.
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Unread 07-12-2013, 01:48 PM   #21
Jonny Jeep
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The resistors fail and switch/wiring melts because of old blower motors supposedly drawing excess amounts of current. I don't know how much current a new/good motor should draw, but it would be nice to know. That way if the current draw can be measured people could decide if a replacement blower motor would be the best way of preventing the problem recurring. Might even measure mine over the weekend, my multimeter will handle 20A which should be plenty.
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Unread 07-13-2013, 03:39 PM   #22
Majnoon
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Jp magazine that started the relay mod started having it fail and now recommends a new fan and switch. Saying the new fan would have less resistance. I bought little circuit board heat sinks off amazon and made the back of my switch look like a copper porcupine. Still using old fan and have had no issues since. It is my third switch and second resistor. (Made resistor look like a copper porcupine too) seems like the ac duct behind the switch makes it down right cold now. My aftermarket aluminum knob gets cool to the touch.
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