Heater switch broke (I think)

[98_XJ_Classic]

Ok my blowers switch only workls on the 4th setting, I havent looked at anything yet so any and all ideas would be great.

 

[AaronsJeep]

Yeah it should be your fan speed switch going bad. Go order one and when it comes in, yank that whole heating/cooling control module from behind the chinsy plastic dash, be careful and unplug the connector, pull the screws that is holding it in place and just reverse the order with the new one.

 

[Blaine B.]

No, it is the fan RESISTOR if it only works on the highest speed. You have a 98 XJ I see? I'm not sure where the resistor will be for yours but for pre 97 it is mounted to the left of the air recirculate door under the passenger side dashboard.

 

[AaronsJeep]

On mine, the switch is the resistor, which is why I can and have replaced it before, I think for around $12 new.

 

[Pelican]

Just curious what you mean when you say the switch is the resistor? What year?

 

[silver_s13]

Just curious what you mean when you say the switch is the resistor? What year?

It doesn't matter

he's wrong

 

[winterbeater]

Resistor, not switch. Accessable without removing module. If resistor blows again soon, you need new blower motor. Well known process with high speed only being the telltale symptom. If you go through carwash, etc. make sure to turn blower off. Goal is to keep water out of the blower motor.

 

[98_XJ_Classic]

Resistor, not switch. Accessable without removing module. If resistor blows again soon, you need new blower motor. Well known process with high speed only being the telltale symptom. If you go through carwash, etc. make sure to turn blower off. Goal is to keep water out of the blower motor.

where is the blower motor resistor on a 98?

 

[Blaine B.]

Reading my 2000 XJ manual (which will be the same as 1998) it says to remove the kick panel cover from the AC/Heater housing and the resistor will be behind there.

Unfortunately it does not give a diagram or anything. I have a 95 so I cannot tell you exactly where it will be in your 1998 either. But hopefully those words from the FSM will guide you.

Edit: I found a diagram further down in the 2000 FSM. Pretty crappy but it appears to be right near the recirculate door, which is pretty much in the same location as my 95.

 

[Pelican]

Water in the blower motor?

 

[winterbeater]

One of my recent jobs was warranty engineer for automotive HVAC systems. Our most common problem was blown resistors and bad blower motors. The motors would usually have signs of water even though by the time we got them they would be dried out. The motors are air cooled so the air flowing through the HVAC also flows through the motor. Some of the dealership reports told of blower motors and fan wheels being a block of ice when they were removed. If you leave the power on to the motor when it's frozen, it can also cause commutator damage. Usually this just makes the motor noisy, (after it blows the resistor). By they way, the resistor is also cooled by the HVAC airflow. That is why it is placed inside the housing. The slower speeds are created by bleeding off current into heat by the resistor (so it gets hot). If it gets too hot, the thermal fuse melts. Most of the new vehicles have gotten away from this old "toaster" style resister and have went over to electronics with a cast aluminum heat sink.

Bottom line tips for reducing problems: Turn blower off in car wash. Turn blower off if it isn't blowing and you think it could be frozen. (Try it again later after it might have a chance to thaw from the heater core warming it up.) Keep the air inlet under the windshield as free of snow and debris (pine needles, etc.) as possible.

 

[Xjcj3a]

so is that diagram right for 92's aswell?

 

[makkman]

I hate to replace 2 parts. the customers hate it. but do yourself a favor, and replace the blower motor at the same time. resistor packs don't fail for no reason. Next, the blower motor will start to squeal when cold.
Otherwise, you get to replace the resistor again in 6 months... and again 6 months after that.
go ahead. ask how i know.
Sam

 

[flht1997]

there is a good chance that when you take it out it will be rusted out and not burned out.
pull the glove box out, then the plastic cover by the passenger feet, there is a couple screws that are hard to get at, 1/4 or 5/16 size i do not remember. there is one way in the back but leave it and just bend it down. then pretty much straight in the middle will be a little gray plastic diamond/square shaped thing about 2 inch wide with two little screws. unplug it take it out and replace.
switch is about 55$. NAPA usually has it in stock
good luck

 

[lawsoncl]

I hate to replace 2 parts. the customers hate it. but do yourself a favor, and replace the blower motor at the same time. resistor packs don't fail for no reason. Next, the blower motor will start to squeal when cold.
Otherwise, you get to replace the resistor again in 6 months... and again 6 months after that.
go ahead. ask how i know.
Sam

Its the blower motor drawing too much current and burning up the resistors, or is the issue that the blower is running too slow and not flowing enough air over the resistor?

If its a current issue (my assumption), you should be able to check that with a meter before blindly replacing the blower.

 

[Blaine B.]

I don't think the resistor failing would mean that the motor will be failing in short order.

You could go to a junkyard and pull a resistor. That's what my friend did and it was fine. The junkyard has a bunch of OEM parts that are probably alot better than today's China made aftermarket parts.....although alot of people frown on Junkyard parts because they are, afterall, in a "junkyard" and not brand new. Although you can save some cash and end up in the same place you could have buying new, or even end up in a "better" situation due to what I mentioned about the China made cheap replacements and such that are out there in increasing numbers!

 

[red_01_xj]

I just fixed this a few days ago on mine here is the write up I used, virtually the same

http://www.geocities.com/chmwatson/FAQs/Jeep/HVAC-fuselink_fix.html

 

[winterbeater]

You definately could get a resistor at the junkyard. $55 is a lot to pay for a new part like this. BUT bring your ohmeter and check for continuity actoss the thermal fuse. And look at the "toaster" wires to see that they aren't too burned. If it checks out OK, it'll be every bit as good as a new one. They don't "wear out" like a motor.

The normal dealership procedure is to replace the resistor once, and if it happens again, replace the motor and the resistor. The blower motor could have been wet or frozen up making the resistor blow. In studying warranty case histories of these issues, most never had repeat issues.

 

[Markos]

Bringing this back up from the dead. Does anyone have a writeup on replacing this in a 97+? The link in the previous post is dead. I'll check the FSM, but I'm a sucker for color pictures.