Help: diagnostic procedure for failed rear wiper.

[doitmyself]

2014 Jeep Patriot. When I turn the column switch on for rear wiper, the arm moves about one inch. On/off several times moves the wiper arm an inch each time. If I leave switch to on, I can manually grab the arm and wiggle it to cause motor to move the entire swath forth and back. Everything else on the column switch works - front wipers, washer pump (front/rear). I replaced the wiper motor, no change. Fuses o.k..

This vehicle has Chrysler's TIPM. My Autel scan tool in NOT bidirectional. The service manual simply states "diagnosis requires scan tool".

What steps to diagnose this problem? TIPM, Switch, wiring, ground? Thank you very much.
EDIT: I did install a new radio about a year ago with pre assembled Crutchfield harness - I don't "think" these 2 correlate - wiper stopped several months later.

 

[Kira]

Wires in the hinged part of the rear hatch bundle can fray. Intermittent operation results.
My rear wiper died.
I opened the rear hatch after leaving the switch ON and the wiper jumped to life as I opened the hatch.
All designs have wires feeding the hatch.

Another place where things go wrong is in the "switch & contact" box, if your design has one.
The contacts can corrode heavily with or without water leaks.
A seal fails on my vehicle's design allowing the box to fill with water.
Since your wiper cycled after you 'manually wiggled' it, I'd guess your problem might be there.

 

[doitmyself]

Wires in the hinged part of the rear hatch bundle can fray. Intermittent operation results.
My rear wiper died.
I opened the rear hatch after leaving the switch ON and the wiper jumped to life as I opened the hatch.
All designs have wires feeding the hatch.

Another place where things go wrong is in the "switch & contact" box, if your design has one.
The contacts can corrode heavily with or without water leaks.
A seal fails on my vehicle's design allowing the box to fill with water.
Since your wiper cycled after you 'manually wiggled' it, I'd guess your problem might be there.

Thanks Kira. That starts to give me ideas. Maybe I have a frayed wire that allows insufficient amps to power the motor. When I flip/flop the column switch, maybe a surge of power overcomes the frayed wire just a tiny bit? I believe the Chrysler TIPM (Totally Integrated Power Module) is the "switch & contact" box you refer to (no separate relay box) . These TIPM's have a love/hate reputation. I will pull it off and check all connections underneath.

Any recommendations to use a multimeter for diagnosis?

 

[Trav]

Check the power wire at the motor for voltage with it switched on. Check the ground at the motor to a ground with a DVOM and in the left rear quarter panel per the diagram.
Check for corrosion at the motor connection and the module on the left side of the engine compartment. What motor did you get? OE or reman?

 

[doitmyself]

OE new MOPAR motor (one of many things I learned from you) thru Rock Auto (looks legit).

Just did a bunch of wire wiggling from TIPM to motor. Nothing. The motor/wiper blade DOES move an inch every time I slam the lift gate closed. Makes my "diagnostic blinders" think it's something in the lift gate. Can't use my DVOM until later today.

Thank you for the input.

 

[zzyzzx]

Stellantis TIPM's are famous for failure. Having written that, I would disconnect the electrical connector at the motor and test it independently first.

 

[PontiacHO]

Some wiper systems are always “hot” with the wiper switch that applies ground. Either way, frayed wires have to be fixed probably.

 

[wtd]

Do a voltage drop test with your multimeter on both the power and ground to the motor with the circuit loaded. This will let you know if you have full power to the motor and if your ground is good.

It looks like a pretty simple circuit. The diagram shows a connector between the TIPM and motor which could be causing some voltage drop if the connector is not making good contact or corroded.

Also check the signal wire from the TIPM to the motor to see if you are getting the command to the motor and at the correct voltage.

 

[Nukeman7]

Another place where things go wrong is in the "switch & contact" box, if your design has one.
The contacts can corrode heavily with or without water leaks.
A seal fails on my vehicle's design allowing the box to fill with water.
Since your wiper cycled after you 'manually wiggled' it, I'd guess your problem might be there.

OE new MOPAR motor (one of many things I learned from you) thru Rock Auto (looks legit).

Just did a bunch of wire wiggling from TIPM to motor. Nothing. The motor/wiper blade DOES move an inch every time I slam the lift gate closed. Makes my "diagnostic blinders" think it's something in the lift gate. Can't use my DVOM until later today.

Thank you for the input.

While the Stellantis/Mopar TIPMs are generally troublesome, your problem in the Jeep is not there.

The fact that the wiper arm moves when manually assisted and when you slam the lift gate clearly indicates the problem is in the electrical contacts inside your wiper motor assembly. It doesn't appear to be a frayed wiring problem since that would not be affected when you only wiggled the wiper arm. I'd highly guess the contacts/brushes in the motor assembly are oxidized or worn and makes intermittent contact similar to a failing starter. If you can access/open the motor assembly, try cleaning the contacts with a good contact cleaner like DeOxit Gold.

 

[97prizm]

2014 Jeep Patriot. When I turn the column switch on for rear wiper, the arm moves about one inch. On/off several times moves the wiper arm an inch each time. If I leave switch to on, I can manually grab the arm and wiggle it to cause motor to move the entire swath forth and back. Everything else on the column switch works - front wipers, washer pump (front/rear). I replaced the wiper motor, no change. Fuses o.k..

This vehicle has Chrysler's TIPM. My Autel scan tool in NOT bidirectional. The service manual simply states "diagnosis requires scan tool".

What steps to diagnose this problem? TIPM, Switch, wiring, ground? Thank you very much.
EDIT: I did install a new radio about a year ago with pre assembled Crutchfield harness - I don't "think" these 2 correlate - wiper stopped several months later.
View attachment 272291

Sounds like either a short or more likely a motor thats binding maybe due to worn bushings or bearings.

 

[doitmyself]

Sounds like either a short or more likely a motor thats binding maybe due to worn bushings or bearings.

Nukeman7

The fact that the wiper arm moves when manually assisted and when you slam the lift gate clearly indicates the problem is in the electrical contacts inside your wiper motor assembly.

As stated above, I replaced the motor with a new OE MOPAR one. Tried it without the wiper arm installed (bind?). Rubber window bushing seems fine. I'm going after a wiring issue initially. I don't have the diagnostic tools (bidirectional) to test the column switch or the TIPM functionality.

I will follow up when I get time to work on this (outdoor spring busy season in progress). THANKS EVERYONE - got me started with some diagnostic steps/procedures (one of my biggest challenges as a DIYer - avoid parts changing, follow logical steps).

 

[KrisZ]

I wouldn’t rule out a mechanical issue. Perhaps the wiper mechanism is binding somehow and it causes a spike in the current so the system shuts it off.

 

[97prizm]

I wouldn’t rule out a mechanical issue. Perhaps the wiper mechanism is binding somehow and it causes a spike in the current so the system shuts it off.

I have seen "brand new" parts bad out of the box as have members on this board.

 

[Marcozi]

BC you can assist the wiper's movement I suspect that this is wiring problem. Why? That motor needs electrical power (DOH!). Power is measured in watts. Multiplying voltage by current (amps) gives you the number of watts. The wiper motor may be getting full voltage but not the current it needs to move. Therefore, it's not getting enough watts of power. That could be bc of partially broken wires.

 

[doitmyself]

Finally!...............I had time to pursue this, but still came up empty handed. I have 14.0 volts to the motor. The ground seems good. Not sure how I would test the signal wire. No corrosion evident. I poked and prodded quite a bit looking at the wires where I could.

I still have the same symptoms: the wiper arm will move an inch when I flip the on/off column switch back and forth. The wiper arm will go through the entire range if I wiggle it......it will move to fully left position in one movement and stop there, if I keep wiggling it will eventually return to full right (park) position in one movement.

I don't have the knowledge or bidirectional tool to proceed. Thanks for all the suggestions.

 

[Donald]

Finally!...............I had time to pursue this, but still came up empty handed. I have 14.4 volts to the motor. The ground seems good. Not sure how I would test the signal wire. No corrosion evident. I poked and prodded quite a bit looking at the wires where I could.

I still have the same symptoms: the wiper arm will move an inch when I flip the on/off column switch back and forth. The wiper arm will go through the entire range if I wiggle it......it will move to fully left position in one movement and stop there, if I keep wiggling it will eventually return to full right (park) position in one movement.

I don't have the knowledge or bidirectional tool to proceed. Thanks for all the suggestions.

Having the right voltage with the motor not running is not the same as having the right voltage when the motor is connected.

My 93 Suburban had a contact assembly that controlled the wiper motor and brought it back to park when you turned the wiper off. Mine broke in my Suburban and I could get it work with a wrap of my knuckle but I replaced it. Something controls the wiper motor bringing it back to park when you turn it off. I would think that is where the problem is.

 

[doitmyself]

Thank you Donald. I'm testing the voltage in the harness connector installed to the motor and on (see pic). But your contact assembly is in mind - my wiper arm moves when I rap/vibrate the motor. I think my motor is controlled by the TIPM signal wire.

I have a new clue: I have ground with the ignition off. When I turn the ignition to on, I lose ground, there is a brief ground as I turn key to start, then no ground. Turn ignition off, and I have to open/close the driver door for ground to start back up.

Could my aftermarket radio install 8 months ago be the problem? You know how the radio continues after engine shut off until you open the door? I took the radio fuse out with no difference. I used a Crutchfield pre-wired harness for my car.

 

[wtd]

Thank you Donald. I'm testing the voltage in the harness connector installed to the motor and on (see pic). But your contact assembly is in mind - my wiper arm moves when I rap/vibrate the motor. I think my motor is controlled by the TIPM signal wire.

I have a new clue: I have ground with the ignition off. When I turn the ignition to on, I lose ground, there is a brief ground as I turn key to start, then no ground. Turn ignition off, and I have to open/close the driver door for ground to start back up.

Could my aftermarket radio install 8 months ago be the problem? You know how the radio continues after engine shut off until you open the door? I took the radio fuse out with no difference. I used a Crutchfield pre-wired harness for my car.View attachment 275848

According to the diagram, this motor is hard grounded to the left rear quarter panel. Have you checked the connection there? Did you do a voltage drop test at this ground connection point like I suggested above?

You should be checking the ground with the circuit loaded so Key on, engine off to get an accurate measurement. Since you said that you lose ground when you turn on the key, how much voltage are you getting on the ground circuit with the key on?

 

[doitmyself]

Thank you wtd. The hard ground to the left quarter panel is buried behind interior trim panels that I have not figured out how to remove. See the very left of this picture with all interior trim removed. https://imgur.com/gallery/jeep-patriot-headliner-removal-DfCPN. It doesn't just pop off, and it seems like there is a procedure and number of steps/order removing these panels.

So, I just checked ground with a continuity test to several other places inside the car body, i.e., the seat belt bolt into the body, that silver rectangular seat latch in the picture center, etc.. I thought that if I have a ground to anywhere on the body, then the connection in the left rear quarter panel is good? Maybe not?

I did not check the ground voltage/voltage drop you recommended. I will do that next. Thank you very much. Not sure of my time frame - its planting season and I am away for days at a time, then get home to the "honey do list".

On the Patriot Forum, they said if I had a better, bidirectional scan tool, I could over-ride the TIPM and send a signal to the rear wiper to test it. This project is getting beyond my skill level, but willing to try.

 

[wtd]

Thank you wtd. The hard ground to the left quarter panel is buried behind interior trim panels that I have not figured out how to remove. See the very left of this picture with all interior trim removed. https://imgur.com/gallery/jeep-patriot-headliner-removal-DfCPN. It doesn't just pop off, and it seems like there is a procedure and number of steps/order removing these panels.
View attachment 277653
So, I just checked ground with a continuity test to several other places inside the car body, i.e., the seat belt bolt into the body, that silver rectangular seat latch in the picture center, etc.. I thought that if I have a ground to anywhere on the body, then the connection in the left rear quarter panel is good? Maybe not?

I did not check the ground voltage/voltage drop you recommended. I will do that next. Thank you very much. Not sure of my time frame - its planting season and I am away for days at a time, then get home to the "honey do list".

On the Patriot Forum, they said if I had a better, bidirectional scan tool, I could over-ride the TIPM and send a signal to the rear wiper to test it. This project is getting beyond my skill level, but willing to try.

Having a good ground elsewhere in the vehicle does not mean that the ground for your particular circuit is good. The ground for your particular circuit is where you need to test.

The problem with continuity tests is that they don't tell you if the wiring can carry a load. Say you have a 20-strand wire and every strand but one is broken. Your continuity test will still show good but if you loaded that circuit, it would probably burn and break that one strand that is left.

What is the voltage reading of the signal wire at the wiper motor when you turn on the switch to activate it?