It was working intermittently and is now deceased. Is there a test to determine where the problem is? Dash switch? Regulator? Motor?

 

Did you do the Fonzie method?

 

I don't think that there is an actual test, could be the regulator or the motor. The Fonzie method is where you give it a bang above the door speaker,that's were the motor is, this should wake it up, if it does that means that the motor may be at fault..

 

+1 on the fonzie method , then if it fails again it on its way out. You have to determine if its just the motor or a snag in the window regulator , get behind the door panels and check the cables , linkage and the motor connection. Also its good to check the toggle bank in the center to make sure the plug in the back its clipped in and secure , if both windows don't work the plug might have came out.

Here is the diagram to help:



Window Electric Motor - Front Left -6/2005

http://www.ecstuning.com/Search/SiteSearch/67626955875/



&

Window Electric Motor - Front Right ( passenger ) Part # 67626955876 -6/2005

http://www.ecstuning.com/Search/SiteSearch/67626955876/




And the window regulators.

Window Regulator - Front Left ( driver ) Part # 51337039451 -6/2005

http://www.ecstuning.com/Search/SiteSearch/51337039451/



&

Window Regulator - Front Right ( passenger side ) Part # 51337039452 -6/2005

http://www.ecstuning.com/Search/SiteSearch/51337039452/



Thanks

 

Definitely go with the fonzie. I did on my '04 R50 probably 4 or 5 times over the 4 years i had it. I disagree that it indicates something is failing; after smacking it, it would work fine for many months. The window motor just sticks sometimes.

 

If it's the motor, try the fix on this link:
https://www.northamericanmotoring.co...-fix-free.html

It worked for mine, and didn't cost a penny.