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Blower only works on high...

126K views 68 replies 46 participants last post by  Old Dogger 
#1 ·
2003 TJ 4.0 5spd. So the heater fan only works on the highest setting...nothing happening on the other three settings. Blower motor or the switch? Has anyone seen this before? If this is a common failure, it might save me some time on the troubleshooting side of things. Thanks.
 
#2 ·
The fan only working on high is normally due to a defective resistor pack. The resistor pack is used for all speeds except for the fan's highest speed where the resistor pack is bypassed. Your 2003 has it in a different location than my '97 does but yours should be somewhere up above the passenger side footwell. It's easily swapped. :)
 
#3 ·
Sweet! Thanks for the heads up! That definitely gives me a head start on the troubleshooting. I'll take a look at the service manual and see wherethe resistors are. I'm sure I can check the circuit with a DMM.
 
#6 ·
Gotcha. I wasn't expecting a bank of axial lead components but I wasn't sure what to look for either. Thanks. I expect it's a pluck and chuck situation.
 
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#8 ·
I have the same proble here as Hondarider... ONLY the high speed is working on my blower motor. I checked the switch selector with a multimeter, and I think the switch is ok..according to a continuity test.
I have 97 wrangler... I har it can be the resistor? Where is it? what does it lok like?
Thanks for your help
jake
 
#14 ·
Replaced this in my 04 last fall. Super easy. Glad I did. I don't like blasting the heat or AC.
 
#17 ·
Could be a resistor pack, but I'd check the wiring to the HVAC controls in the dash...often times problems like that are due to melted wiring at the switch.
 
#19 · (Edited)
Was able to replace fan motor resistor for '99 TJ with a wrench and a new $47 NAPA brand fan motor resistor in about 10 minutes.

Differential diagnosis for faulty AC/heat fan speeds: (1) faulty fan motor resistor, (2) shot fan motor, (3) HVAC manual dashboard control defect, (4) faulty fuses, and/or (5) underlying electrical failure of indeterminant specificity requiring advanced diagnostic workup.

Youtube has several good instructional videos on how to replace the resistor. For example: http://www.youtube.com/watch?v=kikg3uoeNLc
 
#20 ·
switch

2003 TJ 4.0 5spd. So the heater fan only works on the highest setting...nothing happening on the other three settings. Blower motor or the switch? Has anyone seen this before? If this is a common failure, it might save me some time on the troubleshooting side of things. Thanks.
just went thru this same thing last week it was the switch in the dash. i found out the hard way after i bought a new resister and that wasnt it!:doh:
 
#21 ·
I had the same problem in the fall. Only high speed would work, sometimes. I replaced the resister and that didn't work. I almost went the blower route but decided to replace the heater control assembly instead after reading some good posts on this AWESOME Forum. Glad I did it was a 30 min at most $90 fix. It turned out the vacuum switch was shot and the back side of the assembly was a little melted which I think caused the vacuum switch to sit in a bad position and fail. According to some of the jeep parts websites you can replace each one of the heater switches/selectors individually, just another decision you may want to consider. It only takes a few minutes to take apart the dash an take out the assembly. I was able to tell my issue as soon as unscrewed it from the dash. A little wiggle on that switch and everything worked as it was supposed to. You may even be able to wiggle that switch from the glove box. Good Luck!
 
#22 ·
Mine went out on a 97 TJ

My fan would only work on high and the switch from floor to defrost had stopped working also. Removing the leaves that had filled up in there fixed the switching from floor to defrost and the resistor fixed the speed control.

What in the world did we do before the internet?

:thumb:
 
#25 ·
My jeep is doimg the same. Only works on the 4th setting. So i got all or nothing..literally. Hah so i was near autozone today and they said it was 45 bucks. Is that too much for one as i saw on here its a 20 dollar fix or so?
 
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