Case Study: 2005 Touareg, wipers inoperative

Took an odd phone call today. Caller was dealing with a 2005 Touareg and the wipers didn't work, and could not scan address 68 - Wiper Electronics. If I understood him correctly, he got a used unit, no change. Got a second used unit that was tested prior to being removed and was confirmed to be a working unit, but once installed into the project vehicle, wipers did not work.

• Tested power and ground, good. Even load tested with a fog light bulb, no problem.
• Checked Gateway wiring for voltage activity, checked out good.

Noticed in the wiring diagram, the wiper motor, J400, has the Gateway wiring daisy chained off the radio. Odd, but whatever. Informed that the radio is in SAFE mode, but that shouldn't effect the wipers. Have the tech try to scan the radio, address 56. No luck. Remove radio and unplug. Wipers still not working.

So I start digging through the wiring diagram and put 2 and 2 together and notice, the wiper motor is on the Infotainment Gateway, not the Comfort Gateway. So more digging we start looking for other modules on the Infotainment Gateway:

• Telematics, J499
• Roof Display Unit, J702
• Vehicle Position Recognition Module (compass), J603
• Amplifier, R12

Kind of worked our way through, did have a J602, but not a J702 or J499. The last item, the R12 is located in the right rear of the vehicle. Had to remove a few items to get to it and unplug it. With the Amplifier unplugged, the wipers started to work again. The R12 was corrupting the Infotainment Gateway, so no module on that network could communicate. Also learned that in address 19 - CAN Gateway, there was a fault code for the Infotainment Gateway.

The two big things to take away from this.... expect the unexpected... and knowing how to read the wiring diagrams can be the difference between a 20 minutes of diagnostics and 2 weeks of chasing your tail. I don't know how long the tech has been working on this prior to calling.

I swear, the Germans are still at war with us.

TLDR: wipers don't work, unplug amp.

Jef said:

TLDR: wipers don't work, unplug amp.

Click to expand...

filed.

I swear, the Germans are still at war with us.

Click to expand...

Yep. Still mad about the big one.

[h=1]49 CFR 571.104 - Standard No. 104; Windshield wiping and washing systems.[/h]
[h=1]49 CFR 393.78 - Windshield wiping and washing systems.

[/h]
The National Highway Traffic Safety Administration has a legislative mandate under Title 49 of the United States Code, Chapter 301, Motor Vehicle Safety, to issue Federal Motor Vehicle Safety Standards (FMVSS) and Regulations to which manufacturers of motor vehicle and equipment items must conform and certify compliance.


FMVSS 209 was the first standard to become effective on March 1, 1967. A number of FMVSS became effective for vehicles manufactured on and after January 1, 1968. Subsequently, other FMVSS have been issued. New standards and amendments to existing standards are published in the Federal Register.
These Federal safety standards are regulations written in terms of minimum safety performance requirements for motor vehicles or items of motor vehicle equipment. These requirements are specified in such a manner "that the public is protected against unreasonable risk of crashes occurring as a result of the design, construction, or performance of motor vehicles and is also protected against unreasonable risk of death or injury in the event crashes do occur."
This booklet lists the Federal Motor Vehicle Safety Standards in effect as of December 1998, and provides a brief description of each safety standard. It also provides a brief description of other Federal consumer information regulations and requirements.

Click to expand...