Slow Windshield Wiper Operation.......

[Wild Comanche]

I have a 1989 Jeep Comanche.  About a year ago I installed a new wiper motor.  At the same time I replaced the replaceable bushings in the linkage.  Lubricated wear points that were obvious.  Reinstalled and tested.  Very slow wiper movement on the slow and fast settings.  Slower movement than any vehicle that I have owned.  The reason I replaced the motor was because of this very problem.  Very slow wiper speed.  Thinking that the motor was worn out.  Now I am wondering if the motor is getting lower than normal voltage.  Is there a wiper relay on this year of vehicle?  If so, where is it located?  What else could cause this slow wiper movement?  The wipers are not noisy.  Seem to be smooth in movement, but extremely slow.  Thanks........................

[cruiser54]

check this out:

 

CRUISER'S MOSTLY RENIX TIPS

IMPROVING BLOWER MOTOR PERFORMANCE

NOVEMBER 28, 2015 CRUISER54 24 COMMENTS EDIT

On 87 to 90 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. 

[Wild Comanche]

Thanks for the reply and your many tips.   I have refreshed many grounds on this Comanche after reading your section on grounding.  And bought some "OxGard".  But never noticed the grounding spot by the windshield washer reservoir.  I will get that and the new grounding spot on the passenger side.  Seems like there is an intermittent wiper module located under the steering column area that is no longer in production that can cause problems.  Saw where a guy drilled out the rivets and cleaned the old one up and reassembled with zip ties.  I don't know if this could cause slow wiper movement.  I also read on a post that this module controls the operation of the blinkers,  but don't know if this is correct.  My emergency blinkers even with a new flasher relay will sometimes work normally and then slow way down for 5 or 10 seconds and then speed back up to normal flashing speed.  This didn't change with 2 new flasher relays.  One a thermal type and the other an electronic type.   

[HOrnbrod]

1 hour ago, Wild Comanche said:

Seems like there is an intermittent wiper module located under the steering column area that is no longer in production that can cause problems.  Saw where a guy drilled out the rivets and cleaned the old one up and reassembled with zip ties.  I don't know if this could cause slow wiper movement.  I also read on a post that this module controls the operation of the blinkers,  but don't know if this is correct.

 

I have never heard of the intermittent wiper module causing slow wipers. And this module has nothing to do with blinkers either.

 

Do you have an intermittent module on your MJ? If so you can pull the harness connectors from each end of the module and plug them together to eliminate the module for testing purposes. And yes, there are still a few NOS modules available (~$200/ea  ), and there are plenty of "pre-owned" on Ebay. Search for p/n 56006957.

[Wild Comanche]

I refreshed the existing ground on the driver's side (forward of the windshield washer reservoir) inner fender and also broke the ground wire coming from the blower motor, soldered the two ends into an eye and secured the eye to a bare metal spot on the passenger side inner fender area.  Tried the windshield wipers and blower for function.  The wipers seem to rotate a little faster than before and the blower is putting out a good volume of air.  But I discovered something that I never noticed before.  This vehicle has lost the two speeds of the wiper function.  When this problem began I have no idea.  I still have the mist function.  I still have the delay function.  But when the "Lo" and "Hi" positions are used there is no difference in the speed.  Or at least I can't tell a difference.  In both positions the wipers operate at about the same speed.  Whether I have lost the "lo" or "Hi" speed is unknown to me.  The wiper motor is new.  The wiper linkage is in good shape.  I installed new bushings where possible and lubricated the rest of the linkage pivot points.    I wonder if the intermittent wiper module could be at fault or the switch assembly in the steering column?  Or is there some other electrical device that enables the two speeds?  Thanks......again......

[HOrnbrod]

Read the last paragraph on my previous response. Take the module out of the circuit as above and try the wipers w/o the inline module connected to see if there is any change in wiper speed.

[Wild Comanche]

Tried wiper functions w/o the module installed.  Now I know the difference in the two wiper speeds.  I had lost the "Hi" speed with the module installed.  Checked the internet and couldn't find any site that still had part #56006957 in stock.  Apparently a discontinued part.  Looks like Ebay or a wrecking yard.  But definitely a used part.   And three options: Live with the loss of one of the wiper speeds or Buy a used one or Try to repair the existing module.  I think I'll try to repair the original, If I can't I'm no worse off than now.  It has 4 small rivets holding the cases together.  Thanks for the input..................

[Wild Comanche]

As "Hannibal" of the "A-Team" used to say, "I love it when a plan comes together".   Don't know how long it will function correctly, but I got the two speed wipers back.  Drilling the small rivets out was the hardest part w/o damaging the plastic box.  Didn't see any overheated electronic parts on the circuit board.  Cleaned up the points with #600 wet/dry sandpaper.  Sprayed the points with electronic cleaner and blew it off with compressed air.  Used small zip ties to retain the cases.  Thanks for all the advice..............................

[SVPete]

^^^^Hmmm....that's good to know^^^^^

[HOrnbrod]