New fan switch fixed blower, then died

[t00th]

Hey all. I know the blower issue has been covered at length but I haven't found my particular set of issues discussed, so hoping someone with more experience than me can help point me to the appropriate next step(s). Here's how it went down:

1. I get the jeep. One of the four speeds doesn't work. Not a dealbreaker, goes on for a few months.

2. I lose all fan speeds. I tolerate for a few months. Then I start looking into fixing it. Research, forums, etc.

3. I replace the resistor. No dice. At least that's something ruled out.

4. I replace the fan speed switch. That's it! That was the problem! Fan blows on all speeds for the first time in months, easy fix, love it.

5. A week or two later, the fan dies while in use at highway speed. No fan speeds work. Shit. It's then that I remember that the old switch I replaced did look kinda new.

So ... now what? I have very limited electrical knowledge and skills. But, I think I can assume that the faulty fan switch WAS what was preventing my fan from turning on--but also that there is another issue further up the line that is causing my fan switch to become faulty. Sound right? Anything that is known specifically to cause this?

If it's any help, my A/C switch does seem to work and I hear those little vacuum noises when I turn it on or off.

 

[MountaineerTom]

Did/does either fan speed switch look melted?

 

[t00th]

Did/does either fan speed switch look melted?

I examined the old one pretty thoroughly, and it did not look melted. haven't checked the new one yet. To clarify, the switch has male connectors, so I should be looking at other areas of the plastic housing that may have melted or discolored?

 

[Jerry Bransford]

Could very well be a bad fan motor. They go bad from shorted windings which causes them to draw way too much current which can take out the switch, resistor pack, and/or melt/burn the insulation on the wiring.

 

[MountaineerTom]

What Jerry said.

When I bought my Jeep, the first time I had the HVAC controls out, I noticed the fan speed switch was slightly melted. Not long after my fan motor started squeaking. So I replaced it. Left the switch but eventually it started losing certain speeds And event I had to press the not in to get it to blow at all. Replaced resistor and speed switch.

After examining the switch, it looked like the way it melted, it was not able to hold itself together and I think that’s why I had to press in on it to make it make contact to make the fan blow.

Working as advertised now after replacements. No signs of melting after when I’ve been in there. It’s only been a couple times though.

 

[Imapepper]

Could very well be a bad fan motor. They go bad from shorted windings which causes them to draw way too much current which can take out the switch, resistor pack, and/or melt/burn the insulation on the wiring.

Kinda scary having stuff melt before a fuse blows..

 

[t00th]

Thanks guys, this is really helpful.

So as I understand it, I should next replace the fan itself along with the switch (second replacement, first replacement I assume was taken out by the fan).

Then if THAT doesn't work or I have the same problem with it working and then the switch failing, that means that I have to look elsewhere? Is there something else in the system that could cause my fan switch to go bad? Other faulty wiring caused by the bad fan motor?

 

[Imapepper]

If you have limited to no experience take it to a shop, throwing parts at it until it's repaired is unwise.

 

[Wakeangel]

Try pulling the blower motor/fan out and cleaning it and the housing before throwing more parts at it. I had been having this problem with a '98 Sport. What was strange was that it would intermittently work. Sort of like, hitting a bumb, bamb... Blower works. Though not like it used to. And there was weird humming, whirring noise down under the dash panel. So last weekend, I decide to try and fix it. I pull off the kick panel, only to discover the fan is accessed through the engine bay. Pull the battery, pcm, then the fan. It's full of debris. Pine needles, leaves, dirt, all kinds of stuff. I pull the blower, clean it out, vacuum and blow out the housing, pulled the resistor. The resistor was rusty, looked a bit beat up, cleaned it, put some dialectic grease on all the contact points, put everything back and wow, I have full blower function. It even blew a bunch of dust and crap out of the vents. I do a lot of desert runs with no ac so dust is a way of life.

 

[WDE]

You are treating the symptoms. The cure is a new blower motor.

As the blower motor ages, it starts to draw more and more current. They are fairly cheap and easy to replace.

 

[t00th]

If you have limited to no experience take it to a shop, throwing parts at it until it's repaired is unwise.

I do have limited experience but I've done worse, I know that the fan is a relatively simple job and I'd rather do that myself for a hundred or so bucks than spend hundreds at a shop having them chase down a problem. If the fan doesn't fix it then maybe I have another mess on my hands that's better left to a pro

 

[t00th]

You are treating the symptoms. The cure is a new blower motor.

As the blower motor ages, it starts to draw more and more current. They are fairly cheap and easy to replace.

I'm hoping this ends up being the case. Ordered. Will report back later

 

[Queticon]

Not sure how 'easy' the blower motor is to replace. At least on my '05 I had to remove the entire dash to get to the box with the motor and heater core. I should say, it's not hard, just really involved. And actually kind of fun. You know all that crap you lost behind the dash?

 

[t00th]

Not sure how 'easy' the blower motor is to replace. At least on my '05 I had to remove the entire dash to get to the box with the motor and heater core. I should say, it's not hard, just really involved. And actually kind of fun. You know all that crap you lost behind the dash?

Ah weird, all the vids I've watched show it being replaced through the engine bay. Remove that aluminum panel top passenger side, and it's below that. Seems simple enough, if a little time consuming? But that was on at '01, and mine's a '00

 

[Queticon]

Ah weird, all the vids I've watched show it being replaced through the engine bay. Remove that aluminum panel top passenger side, and it's below that. Seems simple enough, if a little time consuming? But that was on at '01, and mine's a '00

I seem to recall that all changed in the '02 model year.
Here's a video of a guy replacing the heater core:



this is the assembly that houses the motor, heater core, and AC core. The motor is to the right and below that green plug.

 

[t00th]

I seem to recall that all changed in the '02 model year.
Here's a video of a guy replacing the heater core:



this is the assembly that houses the motor, heater core, and AC core. The motor is to the right and below that green plug.

View attachment 118389

In that case thank god I bought a 2000 because that is absolutely not something I'd want to tackle or enjoy tackling. geez.

 

[Queticon]

In that case thank god I bought a 2000 because that is absolutely not something I'd want to tackle or enjoy tackling. geez.

Some of this stuff you have to take a zen approach. It was actually 'easy'. Only one nut was a serious PITA. But since all the stuff you're working on is inside, there's no rust fighting to do. Plus I did a lot of 'while you've got the dash out' stuff.

That said, I hope I don't have to do it again any time soon.

 

[WDE]

I have a 2000, and there is no need to remove the dash. It is accessed on the passenger side firewall under the hood.

 

[t00th]

UPDATE: I replaced the fan and the switch. Bingo! All speeds working great, and much quieter than before thanks to the new fan. But just for shits and giggles, I decided to take the new switch out and put the old switch back in. Still works! Great, now I have a spare, and turns out that this time it wasn't actually the switch.

Shit. It stopped working this morning. I have yet to replace the switch again and see if that works, but also there's clearly another problem that I need to find and address so this doesn't keep happening.

So to recap, here's the chronology:

1.One of the four speeds doesn't work, then months later I lose all fan speeds.

2. I replace the resistor. No dice. At least that's something ruled out.

4. I replace the fan speed switch. Regain all speeds!

5. A week or two later, blower dies while in use at highway speed. No fan speeds.

6. Replace fan AND switch. Then put in old switch, and it still works. So maybe this means that the SECOND time, the fan itself went and the switch was fine?

7. Wrong. It died again. CERTAINLY it can't be that the new fan failed (or can it...?). So I now need to see if a new switch solves it for good. To be clear - once I replaced the fan, it worked with the switch that had previously stopped working. So could this mean that that switch was on its last legs but was able to work better with a new fan, but has now died? Or is it more likely that regardless of brand new fan and switch, there's something ELSE in the system (wiring, ground) that's causing my switches to short out and fail?

Let me know if this is unclear, I didn't do a great job of explaining it. Will check in after I replace the switch to see if that helps. Lucky for me, last time I ordered one Amazon accidentally sent two and let me keep both, so I do have a spare.