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-   -   HOWTO: Replace the MTC Blower Motor Resistor (http://www.jeepforum.com/forum/f67/howto-replace-mtc-blower-motor-resistor-926185/)

colinzj 12-15-2009 11:24 AM

HOWTO: Replace the MTC Blower Motor Resistor
 
Since this comes up with regularity, I tore apart my perfectly good interior to take photos.

Tools Required
1. Torx Bit & Driver — I think it's a T15 or T20. If you've bought a bit screwdriver in the past decade, you should have the one you need.

Time Required
15 minutes, tops, if you've never done it before.
Under 5 for repeat visits.

Why Are We Doing This?
You have the manual air conditioning system and only reliably get air on high.

The German resistor pack Daimler specified most likely has committed or is committing suicide.

Step 1: Remove the Damper
The guts of the HVAC system are hidden behind the glovebox, so it needs to come out. Begin by opening the glovebox.

There are a couple things holding the glovebox in. The first thing to deal with is the damper. If you look on the outboard side of the glovebox, you'll see this:
http://www.panachroma.com/bmr/step1.jpg

It keeps your glovebox door from slamming open. It's held on with a simple pin-and-groove system:
http://www.panachroma.com/bmr/step2.jpg

Grab the beefiest part of the damper arm and pull it toward the rear of the Jeep so it unlocks. Gently pull the pin out of the big hole so the damper arm is free of the glovebox.

Step 2: Lower the Glovebox
With the damper removed, we can now work on taking out the glovebox without breaking anything.

You should see this:
http://www.panachroma.com/bmr/step3.jpg

The orange arrows point to the bump stops that keep the glovebox inside the instrument panel. You now need to pull the bumpstops down past the trim so they clear it.

The easiest way to do this is one at a time; I find the outboard (right) one is usually the trickiest. Don't be afraid to get a little rough with it. The left bumpstop actually has a huge fingerhold you can use.

Once you clear both bumpstops, swing the glovebox out. This picture might also give you a better idea of what the stops look like and how to grab them:
http://www.panachroma.com/bmr/step4.jpg

Step 3: Remove the Glovebox
Now we're clear of the interior and the glovebox can come out.

DO NOT USE TOOLS TO REMOVE THE GLOVEBOX. There's at least one writeup floating around that wants you to use a flathead screwdriver to punch the glovebox off; it's totally unnecessary and you risk breaking the mounting hardware or marring the interior that way.

Open the glovebox about halfway between "normally open" and hanging down. (Roughly like in the photo above.) This will line up the openings in the glovebox mounts so you can pull basically directly backward.

Grab the glovebox as close to the mounts as you can on both sides, and give it a good yank one side at a time. Start with the inboard side—if you do the outside first, there's not always enough room to grab the inside.

Once both sides are free, you may have to wiggle things around a little to get everything to clear the opening. Take your time and set the glovebox aside once it's out.

Step 4: Remove the Blower Motor Resistor
With the glovebox out of the way, we've got clear access to our target:
http://www.panachroma.com/bmr/step5.jpg

Only 2 Torx screws and a connector stand between you and four speeds of heating and cooling.

Unscrew both screws and remove the resistor. Do not unscrew anything else on the HVAC box; you just want to remove the 2 screws on the resistor itself. For clarity, they are called out with green arrows in the photo above.

With the resistor free, it's a lot easier to look at the connector and get it off. It's your typical "squeeze to unlatch" deal. (Hint: It's a lot bigger than you think it is.)

If you're extremely unlucky the connector may be damaged, but in my experience this is way, way less common with the WK than with the WJ. It also seems to be related to running faulty resistors for extended periods, so don't cheap out over an $8-9 part. If your connector is melted, seek professional help unless you're confident in your splicing skills.

Steps 4-99: Reassemble
Assembly is the reverse of removal. :D

As with taking it out, it's easier to put the glovebox back in inboard side first.

Putting it back on the hinges just takes a good shove; you'll feel it lock in, and it'll also be obvious you did it right when it's not flopping around.

Have a beer, you just saved $40+ in labor! :cheers2:

Texas WJ 12-15-2009 11:27 AM

Nice. I added this to the FAQ section.

robtre 12-15-2009 11:52 AM

Its guys like you that make this forum awsome!!! Thank you

glopez2k 12-16-2009 07:48 PM

This is great and friendly advice, I appreciate it.

xOakley 12-16-2009 10:40 PM

that easy, this is happing tomorrow haha

robtre 12-17-2009 08:24 AM

My wife and I were going back and forth Facebook vs Jeepforum she thinks I am obsessed with JF (I am) so I said go onto your facebook and find out how to fix your Jeep for free see what you come up with! That shut her down.

sabre364 12-20-2009 12:41 PM

Great info! Thanks

97tjeff 07-21-2010 07:06 PM

...

colinzj 07-21-2010 07:22 PM

That's why the writeup only says to remove the two Torx screws on the resistor. ;)

I'll swap that last image out with a slightly different one for the visual crew.

97tjeff 07-21-2010 07:49 PM

Quote:

Originally Posted by colinzj (Post 9828162)
That's why the writeup only says to remove the two Torx screws on the resistor. ;)

I'll swap that last image out with a slightly different one for the visual crew.

my bad. I looked at the picture and not the words apparently. well then, great write up all around! :2thumbsup:

colinzj 07-22-2010 12:29 AM

New and improved! Now with 100% more green arrows and red Xs to prevent confusion! :thumbsup:

jager00 07-23-2010 04:37 PM

dude ive replaced that part 2 times and need to again wtf is wrong with it

97tjeff 07-23-2010 11:39 PM

Quote:

Originally Posted by jager00 (Post 9839366)
dude ive replaced that part 2 times and need to again wtf is wrong with it

which ones are you buying? IMO if you're going to Autozone to buy something like this, that's why. This is one thing where the best place to get it is the dealer.

jager00 07-24-2010 09:48 AM

Quote:

Originally Posted by 97tjeff (Post 9841357)
which ones are you buying? IMO if you're going to Autozone to buy something like this, that's why. This is one thing where the best place to get it is the dealer.

i got it from the dealor and it lasted a week or too... and then again... now it works on full blast all the time and low and med. if i slam the glove box lol

MBDiagMan 01-14-2011 06:50 AM

Great forum!

I'm trying to fix the blower on my daughters '05 Laredo while she's on her college graduation trip. I searched and found this thread. I only have this weekend to fix it and can only get parts from the dealer up until Noon Saturday morning.

How is the best way to test the "resistor?" Also I have a wiring diagram for the climate control part of the vehicle and do not see anything called a "resistor." I do see "Module Front Blower Power (ATC)" Is this the same thing? It sounds as if ATC refers to Automatic Temp Control, which hers doesn't have. I may have the wiring diagram for the wrong version.

Thanks for any help or suggestions you can offer, as she and her dog are freezing to death when driving it.

Also thanks very much for the pictorial and other information in this thread!

Doc


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