i have no breaklights on my 1985 .....
iv checked for power at the switch plug by running a tester to it and ground and unplugging it ......it has power when the key is on...none when its off, but if i turn key off n switch my tester to power the plug has ground.......

the actual mechanical switch seems to b working fine, i put power to it with the pedal at rest n the cicuit was broken...i depressed the pedal and the circuit closed (test light came on)

now im going back out to to mess with the tail lights themselves....the breaklight bulbs look fine. 7056 i think they are. so im going to try to figure out what is what on the plug that plugs into the tail light n c if i get power back to it when the break is depressed......

this is my only vehicle at the moment so i kinda got to hustle n get this working tonight ......

Probably an easier way to determine if the circuit is good is to jump the 2 terminals at the BRAKElight switch and see if the BRAKElights come on, if they don't you know the problem is elsewhere. You can then test for power and ground at the sockets in back and go from there.
What model is the car, you only say 1985, which is good to know it is older, but is it an S or E or what is it?

__________________
Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

OK I looked at your profile 300SD

__________________
Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

Have you checked fuses?

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

fuses are good ......no license plate lights either......

so i took the bulbs that i know r good ( blinker) n set it on my ground on the batter n took my test from from the positive and touched it to my buld and my tester lights up on any good bulb i do it to .......when i do it to my break light bulb and my license plate bulbs it does NOT light up......soooooo im hoping that by some freak thing all four bulbs are bad n if i run to the parts store n replace them then maybe ill b ok.......but im not optimistic , how all 4 b bad at the same time?

I also did bypass the brakelight switch and i DO have power back at the tail light plug in a terminal that i did not have power at b4...........

Sometime they blow out within a few months of each other and don't realize it until they are all blown out. I have seen this before though where a problem is just bulbs.

__________________
Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

You stated it has power when the key is on - which position? This sounds normal to me, it should not have power when key is not in position 2.

Does it work when the engine is running? The brake lights should only work with key in position 2 - engine on or off. When you crank the engine and release the key it goes back to position 2.

__________________
http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

change the bulbs

__________________

1990 190E 3.0L

ok so i guess im a Tard! but the bulbs were the first thing i checked! .....in the dark on the side of the rd in front of a the state trooper who pulled me over......i didnt think i could have 4 bulbs go bad all at once! iv only had the car a cpl months n they worked when i bought it.....well sorry for the stuid questions! but i know a bit more about the wiring of my car now lol ......thx guys u r awesome...AND PATIENT!

PEACH PARTS....

....because sometimes the simple solution seems too easy. :-)

Just kidding, but glad you are now familiar with your wiring.

__________________

1990 190E 3.0L

FYI: Diesel Discussion is the designated place for M-B diesel discussion . Nothing wrong with posting here -- wiring is the same between gassers and diesels -- but just for future reference .

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

I think he did well by posting it here, many people never look at diesel discussion, I know I never would have seen it there, I think DD is mainly for diesel-only topics, just my opinion.

__________________
Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

I had years of bulb trouble till I ordered a German set.Now no problems

__________________
1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

I believe DD gets more traffic than Tech Help, so I think the odds of a better response would be better there. Besides, everyone knows that the best Mercedes don't have spark plugs.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.