Where is the rear window defog relay, S420
 

1995 S420. My rear defog does not function, I have checked the fuse and did not find any problem. Is there a relay and where is it located.

Thanks,
DanielW

Here it is..
 

W140 S Class... rear window defog relay is in the trunk on the passenger side... see the attached picture.
Hope this helps.
KenP

on my '88 190e when i turn on the rear window defroster it will never turn off til i turn off the ignition switch. bad relay or bad switch??

I am not sure on your car but on my 1988, 190e, the rear fog relay is incorporated with the intermitant wiper relay. It is a large black box at the back within the fuse box under the hood on the driver's side.

I do not know if your car is wired the same but by chance are your intermitant wipers not working.

To fix mine, I took out the relay cleaned the conenctors and reinstalled. No problem since!

Iggy

thanks KenP
 

Thank you for your picture post --- It was the info I needed. I pulled the cap off the relay and re-surfaced the contact points with 600 grit wet or dry paper. The points did not really look too bad at first, however after cleaning with the sand paper everything worked again. Avoiding trips to the dealer or indy is a GOOD THING. Thanks again.
DanielW

DanielW-
You're most welcome. Glad it helped. Many times the biggest challenge on a W140 is just figuring out where various things are located... :-)
KenP