Blower fan resistors upgrade

[Manche757]

89MJ, 4.0.  Has any clever person come up with a way to do away with the resistors and replace them with something electronic?  Replaced them about a year ago and now it has gone out again.

[Pete M]

interesting.   in what manner have they failed?  is your blower motor pulling more amps than it should?

[Manche757]

I had factory air installed in the MJ that never had ac 2 years ago.  Shortly there after, the blower would only work on low.  I had the fan replaced and shortly there after the resistors replaced.  Fyi, the original resistors did not have a cover over them.  About a year ago, those failed and I had them replaced and those were covered.  A week ago, I had the steering pump replaced that had been replaced about a year ago and also had the turn signal/flasher switch replaced which was probably original.  When I picked up the truck, only the high speed would work on the blower fan. The mechanic said newer cars have gone to something electronic.  Any suggestions?   I am feeling like a government subsidy having stuff replaced that has already been replaced.  

[Pete M]

can't say I remember seeing any upgrades to the resistor packs.    but I've not seen everything yet. 

 

I would pull out the resistors and inspect them.  could be the plug has gone bad, could be the pack. 

 

the cover is to help prevent debris from touching the coils.  they get super hot.  something that the original designers hadn't thought of apparently.   even with the cover they can still set a mouse nest on fire pretty easily.  

[Eagle]

Jeep was still using resistor pack in 2000. I've done three of them in our two 2000 XJs, thanks to mouse nests.

 

[A-man930]

Make sure your blower motor isn't stuck with trash or something. If it's not allowed to spin to it's full speed it will demand excessive current

[cruiser54]

and while you're at it:

 

CRUISER'S MOSTLY RENIX TIPS

IMPROVING BLOWER MOTOR PERFORMANCE

NOVEMBER 28, 2015 CRUISER54 28 COMMENTS EDIT

On 1984 to 1990 MJs and XJs, the blower motor’s factory grounding point is on the driver side inner fender under the sheet metal screw. This ground is shared with windshield wipers, front windshield washers, rear windshield washers, AC clutch relay, fan control relay, fog lamps, fan motor, headlamps, front turn signals, front side markers, and park lamps.

So your blower motor has its ground point 10 feet away from where it is located!!

What we’re going to do is leave that ground intact and also ground the blower motor on the passenger side inner fender much closer to the blower motor itself. This will also benefit the other components on the factory ground circuit. Take this opportunity to refresh the factory ground as a matter of course. Remove the screw, scrape the surface to bare metal and reinstall the screw securely.

Here’s what I do to get the ground much closer to the blower motor and add another ground point to this overloaded ground circuit.

Find the blower motor connector on the passenger side. Red and Black two wire connector.

Find a location where the black wire can be made to reach the passenger side inner fender, and cut the wire. You may have to do some rerouting of the harness to achieve this.

Take both cut pieces of wire and put them together into a yellow eyelet and crimp. Fasten the eyelet to a place on the passenger side inner fender with a sheet metal screw after applying OxGard to the contact surfaces. Be sure to scrape the attaching point on the fender to bare metal first.

Your blower motor will now turn faster and last longer, and the other electrical components on the circuit will benefit from a better ground path. 

Revised 01-31-2016