Fan Knob

JeepBeat · **Posted:** Sat Nov 29, 2008 11:52 am

On my fan control knob (for heat/vent/AC) the speed setting at #3 does not work anymore. I can still select 1,2 or 4 (high) and the fan works. What causes this? Is just a case of needing a new part? I recall this happening in my Chev truck years ago, I had to replace the knob assembly, as the fan wouldn't work at all? I am in no panic, as the fan still works on high and low, but just wondering how to fix. Thanks.

rt_power · **Posted:** Sat Nov 29, 2008 2:16 pm

my guess is the fan selector just like you said. i had this happen about a week ago on my b-van. i was changing the radio and now intermittently works on all speed but three. try pulling it out and just double check the tightness of the connector just to be sure.

corwyyn · **Posted:** Sat Nov 29, 2008 3:33 pm

Most likely the resistor block is going out (a common occurance on the KJs). There are plenty of threads and a couple of how-to's both on here and over at KJ Country.

mrkake · **Posted:** Sat Nov 29, 2008 7:45 pm

corwyyn wrote:

Most likely the resistor block is going out (a common occurance on the KJs). There are plenty of threads and a couple of how-to's both on here and over at KJ Country.

rt_power · **Posted:** Sun Nov 30, 2008 4:02 am

from my experience, when the resistor block is toast you should only get high speed. somebody stop me if im wrong an im not sure how it is circuited but when u lose one of the first three speeds you should lose them all and for high speed is applying full voltage to the motor that why it will only work on high. somebody tell me other wise, i have been wrong before

corwyyn · **Posted:** Sun Nov 30, 2008 6:46 am

My understanding is that the resistors fail due to overheating, but they don't nescessarily fail all at one time. If you look at the schematic for the resistor block:

You'll see that it would be possible to lose the resistors for low and medium #1 but still have the third setting (medium #2) and high. Now if the resistor between high and med #2 were the one that failed then that would open up the rest of the circuit and none of the other settings would work except high. Easiest way to tell for sure if the resistor block is the culprit would be to put an ohm meter on it, but not everyone has access to one.

corwyyn · **Posted:** Sun Nov 30, 2008 6:51 am

OK, that's what I get for reading these things in the early morning. I see that the OP says he has settings 1,2 and 4. That would indicate a switch as the most likely cause and not the resistor block as I first thought. For some reason when I first read the post I had it some other way. I'm going to bed now...

JeepBeat · **Posted:** Mon Dec 01, 2008 3:59 pm

Thanks guys. Should I just pull the knob off or do I take the dash plate off and investigate somewhere else?? Like I say, the fan works on 1, 2 and 4 (high). Just setting 3 that doesn't work on the dial. What and where should I look?

Fan Knob

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