So the other morning went to use my defrost and noticed it wasn't working properly till I turned the speed to 4. 1-3 don't work at all it seems, I checked by placing my hand over the vents and nothing on any of those settings.
This also happens when I tried it with the AC as well as all the other hvac settings.

From what I was able to search on the forum it could be the blower relay, resistor or "melted switch". I'm not good with electrical diagrams so any/all help would be greatly appreciated.
Also I'm moving this week and it's getting colder I'm going to need to use the defroster, am I going to fry anything if I keep using it on the highest setting till I can get it fixed?

 

No problem leaving it on 4 setting at all.

 

likely the blower motor resistor. although some chryslers like to burn up the harness too. as long as nothing is melting and you dont smell fire you should be fine.

 

Good to hear, it might be a week till I can get to this.

 

This is exactly what happens when the blower resistor goes bad. High bypasses the resistor all the slower settings will not work.

 

This is a fairly easy fix?

 

On my 88 it is, not sure on your 98 model but the resistor should be mounted under the dash on the passengers side.

 

To change the blower resistor block do this:

1. Disconnect and isolate the battery negative cable.

2. Remove the kick cover located under the dash, below the glove box. See pic.

3. Remove the connector from the blower resistor block. See pic for reference. Examine the connector closely for signs of overheating/melting.

4. Remove the two screws that attach the resistor block. Remove the resistor block.

5. Reverse the removal procedures to install.

6. Test blower by turning ignition key to RUN and selecting any setting on the AC/Heat control panel using the mode selector. Run the blower on all settings.

Kick Cover:



Resistor location:

 

Thank you thank you thank you! I saw you commented on a few of the other threads I read about similar problems, was hoping you might comment.

 

If I see overheating/melting on the connector is that something I'm gonna have to cut then splice a new one on to?

 

[QUOTE=Vonguido;2650378]If I see overheating/melting on the connector is that something I'm gonna have to cut then splice a new one on to?[/QUOTE]

Replacement connectors with pigtails are confusing to find. It seems the illustrations shown on the auto parts store's web sites don't really match the looks of the actual connector. I've never had to replace mine so I really don't know what you'd be getting if you bought one.

 

Ken comes through again... thanks man. I have the same thing going on... you might've just saved me and my girlfriend's relationship.

 

So I had to revive this thread because I have still yet to fix this with a new resistor. yes I know its been almost 6 months but I had shocks, and steering to replace.

So the hvac still only works when the speed is set at 4, however something new happened this morning when I came to work this morning at 5am. I turned of my Jeep and took the key out of the ignition and the heater was still on...... I was dumbfounded. I turned the hvac to the off position and it stopped. Turned the Jeep back on and then turned the hvac back on again and shut the engine off and it still kept staying on...I tried this for another couple minutes before finally just turning the hvac into the off position and going into work. So my question would be is this from the resistor that I know I need to replace or could it be a fuse or something else? I searched and wasnt able to find a thread with the same problem.

 

Study this schematic.

You'll see that the blower relay control coil is powered from the RUN bus, that is, the key must be in the RUN position to activate the relay. The power contacts in the relay are powered directly off the battery bus.

Note also, that when the Mode Selector is in the OFF position the ground to the blower circuit is terminated.

If the blower relay is defective and stuck in the closed position, the blower running with the mode selector in any position but OFF would be expected, even with the key to OFF.

You'll see the blower motor relay in the pic on the schematic. To get at it you have to roll down the glove box by removing the two rubber stops and let the glove box 'roll down'. The relay is like any in the PDC. just hold the bottom of the connector and pull up on the relay to remove it.

You can borrow the electric radiator fan relay from the PDC and plug it in to see if it corrects the problem. If it does get a new relay, but make sure it's a 40 Amp relay. If it doesn't correct the problem you'll need to do some troubleshooting.

 

Once again CCKen coming to the rescue. I work this weekend at the station so if I get some downtime between calls I will dive in. If not first thing next week. I did buy a new resistor from napa just haven't had the time to put it in yet.