Weird wiper problem! Help pretty please

**b6-sr20det** · 11-29-2008 08:58 PM

So today was the big audi fix er up day for me today and i wanted to just all in one shot fix everything. So I started with the timing belt and water pump. Then i did the stupid coolant temp sensor behind the block.

So after not having wipers for the last 2 months and being my last fix of the day it was on to taking the motor/linkage out and lubing it up with hopes that it would remedy the problem. I was wrong! The linkage moved perfectly with no signs of rust or corrosion. So while it was out i plugged it back in and hit the wipers and it still did nothing? I unfortunetly didnt have my test light so i just grabbed some stripped wire and i tried to power the wiper motor itself direct from the battery and wha-la! the wiper motor free from the linkage spun right up and worked perfect. Being a bit confused i double checked the fuse and it was perfect! My only thought is that the wiper motor for some reason isnt getting any power. So does anyone have any insight on my problem? i searched for a while and didnt find anything! and to make matters worst my check engine light came on again!

Any help would be appreciated! And thanks everyone for the helpful write ups on here! It made everything go smooth today!

**diagnosticator** · 11-30-2008 02:38 AM

A couple of things that could cause the motor to run fine unloaded, but stop with the wiper mechanism load, is the Central Electric Control module is faulty, with the wiper power supply output voltage low or zero volts.
The wiper motor may have a burned out winding inside, leaving the remaining windings unable to generate enough torque to run with a load applied, but will run unloaded.
The wiring connection to the wiper motor power supply may be shorted somewhere.
The ground wire connection from the wiper motor to the chassis ground is faulty, and has a poor connection or high resistance due to corrosion or is loose at the chassis ground connecting point. If this is involved, the motor will run unloaded, but when the higher current draw required to run with a load applied, the high resistance ground causes excessive voltage drop, and not enough power can reach the motor to run with a load applied.

**b6-sr20det** · 11-30-2008 10:20 AM

Originally Posted by diagnosticator

A couple of things that could cause the motor to run fine unloaded, but stop with the wiper mechanism load, is the Central Electric Control module is faulty, with the wiper power supply output voltage low or zero volts.
The wiper motor may have a burned out winding inside, leaving the remaining windings unable to generate enough torque to run with a load applied, but will run unloaded.
The wiring connection to the wiper motor power supply may be shorted somewhere.
The ground wire connection from the wiper motor to the chassis ground is faulty, and has a poor connection or high resistance due to corrosion or is loose at the chassis ground connecting point. If this is involved, the motor will run unloaded, but when the higher current draw required to run with a load applied, the high resistance ground causes excessive voltage drop, and not enough power can reach the motor to run with a load applied.

Thank you for your awesome answer! Last night i actualy pulled the wiper motor apart and there were no signs of burns etc... on the electric winding or anything. Its just weird that it wouldnt do anything from the wiper motor plug but would from direct battery power unloaded. What is the deal with the cecm and are they expensive to replace? I would realy like to have wipers for the upcoming winter.

**diagnosticator** · 11-30-2008 11:02 AM

You will need to test each possible cause until something is found to explain the malfunction. For example, with the wiper switch ON, there should be ~vbatt between the power supply and the ground terminals in the harness connector. If not, test the resistance of the ground between the harness connector and the chassis common ground nearby, it should be less than 1 ohm. If it's too high, the voltage to the motor will be low.
The CECM usually works or doesn't work at all, but the switch inside the CECM is a transistor solid state switch, so it's reliable, but if all else checks okay, then the CECM is the only other possible cause. It's not cheap, a new one is more than $270.
Also check the resistance through the motor, make sure the resistance is fairly even as the motor is turned through a complete revolution. A motor winding can be open circuit, from a break in the winding cause by something other than a thermal burn out. The brushes and commutator is often the location of a poor connection in a motor.

**b6-sr20det** · 11-30-2008 11:22 AM

Thank you again sir! I will be busting out my multimeter this week and going to town!

**b6-sr20det** · 12-09-2008 01:42 PM

Dear Diagnosticator! Your advise is needed pretty please!
well a few days ago I decided to bust out the old circuit tester and see whats up. So i have the car running and i test each pin on the wiper motor connected and i think i found the problem but im not sure how to fix it.
There were 4 wires for the motor
Brown = ground
black/white - green/yellow and green lilac for power supply.
All of them tested awesome but the black/white wire show both a power and a ground when i did the circuit testing! It also showed for power when the wiper switch was off but no other wires did. I am guesing that this wire is bad? I also tested my motor with the wiper transmission on it and it still spun perfect!
So my question is now how do i go about fixing this?
Any advise would be greatly appreciated!
thanks
-mike-

**Smiley** · 12-09-2008 02:16 PM

offtopic

SR20DET ftmfw!!!!

Good luck with ur problem however! I'm sure one of the Audi geniuses will help ya out.

**b6-sr20det** · 12-09-2008 03:14 PM

Originally Posted by GtiRSmiley

offtopic

SR20DET ftmfw!!!!

Good luck with ur problem however! I'm sure one of the Audi geniuses will help ya out.

Thanks dude! yeah my gt3076r sr20det 240sx is my track car and the audi is my daily.lol Anyway some one please helps

Im thinking about just cutting the bad wire all together! I need wipers!!!!

**b6-sr20det** · 12-10-2008 08:27 AM

Bump! Anybody?

**b6-sr20det** · 01-03-2009 06:45 AM

Sorry to bump my older thread guys but with the snow and the yucky weather conditions we are facing in the north east I NEED MY WIPERS lol! Im all out of ideas and ready to trade this cursed car in for a b7 2.0t

**Wanted** · 01-03-2009 08:17 AM

While I'm no diagnosticator by any means I hope I can help.

When you say that all the wires "tested awesome" - what kind of readings did you get at each wire?

**dirtybrd** · 01-03-2009 08:38 AM

You need a wiring diagram. More then likely you have a bad module or relay.

**Wanted** · 01-03-2009 08:42 AM

Great point dirtybrd. X2

**b6-sr20det** · 01-03-2009 09:29 AM

Originally Posted by dirtybrd

You need a wiring diagram. More then likely you have a bad module or relay.

Thats what im thinking myself. When i used a circuit tester on the 4 wires(1-ground /3 powers for different speeds) they all showed up perfect but one! My black/white wire wich i believe is the slower speed for the wiper motor not only did it show that it was getting power but it also showed as a ground

. I then tried cutting this wire thinking it was causing the wiper motor to short to ground and i tried using the wipers at the different speeds by the unaffected power wires but it still did nothing. Im starting to think that it is my cecm but i have had no luck finding one? Does anyone have any useful insight to this odd behavior or where i could purchase a cecm?
any help is always appreciated!
-mike-

**Bradycruze** · 02-15-2011 08:11 PM

Originally Posted by diagnosticator

You will need to test each possible cause until something is found to explain the malfunction. For example, with the wiper switch ON, there should be ~vbatt between the power supply and the ground terminals in the harness connector. If not, test the resistance of the ground between the harness connector and the chassis common ground nearby, it should be less than 1 ohm. If it's too high, the voltage to the motor will be low.
The CECM usually works or doesn't work at all, but the switch inside the CECM is a transistor solid state switch, so it's reliable, but if all else checks okay, then the CECM is the only other possible cause. It's not cheap, a new one is more than $270.
Also check the resistance through the motor, make sure the resistance is fairly even as the motor is turned through a complete revolution. A motor winding can be open circuit, from a break in the winding cause by something other than a thermal burn out. The brushes and commutator is often the location of a poor connection in a motor.

Sorry for the bump i am just having problems with windshield wiper motor and looks like diagnosticator's comment in here is pretty interesting and helpful. Well following what you said is a lot easier than visiting my dealer. Thank you so much you just saved me my hard earned money.

**JA4** · 02-15-2011 08:42 PM

Sorry to bump this, again, but this guy should be the prime example for new members.

Searching for things does work! Congrats on finding a fix and welcome!