Climate control fan missing speeds
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Joined: Nov 2004
Posts: 28
From: Cleveland, Ohio
Climate control fan missing speeds
I got into the car the other day and my climate control fan is only working on 4 and 5. The settings of 1, 2, or 3 are no longer working. Any Ideas? Thanks.
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Joined: Feb 2006
Posts: 945
From: East Granby, Connecticut
I had an issue on my 99 max where the fan speed constantly cycled through all the speeds, which blew out air intermittenly. I couldn't turn it off either, so I just reset the computer and it worked perfectly. Dunno, that may help you here.
I also recall reading somewhere (faq?) that if the blower only works on the the top speed(s) then there could be a problem with the resistors that are used to cycle through speeds, i.e. the resistors that limit the power to the blower motor for speeds 1, 2, and 3, may be busted, where as 4 works and setting 5 has no resistors. Either way, hope it helps.
***EDIT***
I realized after posting that this resistor theory was in that thread posted above.
I also recall reading somewhere (faq?) that if the blower only works on the the top speed(s) then there could be a problem with the resistors that are used to cycle through speeds, i.e. the resistors that limit the power to the blower motor for speeds 1, 2, and 3, may be busted, where as 4 works and setting 5 has no resistors. Either way, hope it helps.
***EDIT***
I realized after posting that this resistor theory was in that thread posted above.
Originally Posted by imjd
Most likely it is the resistor pack.
On lower speeds there are resistors in series with the blower motor to slow it down. On highest speed the resistors are bypassed.
The resistor block mounts to the plastic a/c plenum just downstream of the blower. It has 4 wires coming out of it. You can see it, and remove it, from the passenger footwell.
It's possible for it to fail due to corrosion, so maybe replacing it is all you need to do. However, if the replacement fails quickly, then probably your blower is drawing too much current and you might need a new blower motor as well.
A word of advice, the resistors need the air stream from the blower for cooling. If you try to run the blower with the resistors in still air, they will overheat if you run that way for more than just a few seconds.
On lower speeds there are resistors in series with the blower motor to slow it down. On highest speed the resistors are bypassed.
The resistor block mounts to the plastic a/c plenum just downstream of the blower. It has 4 wires coming out of it. You can see it, and remove it, from the passenger footwell.
It's possible for it to fail due to corrosion, so maybe replacing it is all you need to do. However, if the replacement fails quickly, then probably your blower is drawing too much current and you might need a new blower motor as well.
A word of advice, the resistors need the air stream from the blower for cooling. If you try to run the blower with the resistors in still air, they will overheat if you run that way for more than just a few seconds.
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