HVAC PROBLEM

[Jeepguy819]

Hey there, speeds 1 and 2 on heater fan isn't working, BUT speeds 3 and 4 ARE. Anyone have any suggestions ?b]

 

[Bounty__Hunter]

RE: new jeeper w/dumb question

Sounds like a bad fan switch.

 

[Saurian]

RE: stain

My suggestion would be fan switch, or the blower motor resistor pack, though I don't know if the failure of that component would result in it not working at all, or causing the symptoms like you said...

 

[Jeepguy819]

RE: stain

Thanx,.... is this something a novice can accomplish

 

[jay79cj7]

RE: Re: Another cooling question.

Either of the two above could do it, but I would guess the resistor pack. Not sure what kind of jeep you have, but yes, a novice can do it. I had to change the resistor pack on my XJ and the hardest part was just finding and getting to it under the dash. It was a dealer-only part too.

 

[Jeepguy819]

Its an 02 TJ, thanx,.. i'll head to the dealer today

 

[kraken]

Re: RE: Re: RE: Warning NOT for those that don

hey I have a 02 TJ with the same exact problem. This resistor pack is under the dash? Where is the switch are you talking the actuall knob?

 

[jay79cj7]

I have an 00 XJ... Since the dash layout is so similar, I am guessing the location of the resistor would be too. Mine was under the dash on the passenger side. It was easier to get to by dropping the glove box down past it's catch. It was roughly rectangular in shape; a maybe 2" x 3". There are just a couple resistors that the current is routed through in the blower circuit to control the current going to the motor. Depending on how the switch is turned, the current is routed differently and thus has a different resistance. One of the leads was broken so I had an open circuit. My blower only worked on high. I guess I could have just soldered it.

 

[frankiefire702]

RE: tire question

Yes. if you remove the glovebox the resistor block is right behind it. Remove the lock on the wire harness. Disconnect the harness from the resistor. Then there are two screws holding the resistor in.

 

[frankiefire702]

The resistor runs about 13 bucks at the dealer.

 

[dick_wilderness]

Think this is the same reason I get no heat from the floor or dash vents, only the defrost vents work no matter what setting is on.

 

[jay79cj7]

No, the resistor pack only controls the current to the blower motor. You probably have a problem with one of the motors that opens and closes the ductwork. I know nothing about them...

 

[Saurian]

Alarm always goes off

I think those motors are vacuum controlled, perhaps something has become disconnected...

 

[Sparky-Watts]

RE: Re: RE: Re: RE: Warning NOT for those that don

My YJ has only low and high settings, but sometimes they don't work at all.....when that happens, I grab a handful of wires under the dash and start wiggling them until the fan starts. Primitive, yet effective.

 

[frankiefire702]

RE: Alarm always goes off

Think this is the same reason I get no heat from the floor or dash vents, only the defrost vents work no matter what setting is on.

Yeah dude. Your's sounds like the mode door actuator. That's the motor the controls the door to direct the heat where you want it.

 

[XJNick]

1997 tj sport $8500

Hi,

I guess I could have just soldered it.

That probably wouldn't work because the resistors get HOT and the solder might have melted. That is why they are mounted in the path of air from the blower motor -- to help keep them cool. Pushing 30 amps through power resistors makes heat :mrgreen:

only the defrost vents work no matter what setting is on.

The vacuum motor which controls the defrost air flap defaults to "defrost" when there is no vacuum present to it. So no vacuum = all air out the defrost vents. You probably just have a broken vacuum line (check the main line to the HVAC controls from it's source in the engine compartment to the firewall first as that is likely where the problem is).

-Nick :!: