Mercedes-Benz Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
It was suggested that I post here and would appreciate any help or thoughts with my issue, My S500 started just fine backed it out of the garage so i could clean up. Went out several hours later and NOTHING.... battery is good, all fuses are good,I tried a new starter relay but to no luck, I can jump the relay and it starts (thats how I got it back in the garage) but still cant figure it out. Anyone run across a similar situation? Have any ideas???
 

·
Registered
W220 S320 CDI 2005; W140 S280 1994 (Sold Nov. 2012)
Joined
·
867 Posts
It was suggested that I post here and would appreciate any help or thoughts with my issue, My S500 started just fine backed it out of the garage so i could clean up. Went out several hours later and NOTHING.... battery is good, all fuses are good,I tried a new starter relay but to no luck, I can jump the relay and it starts (thats how I got it back in the garage) but still cant figure it out. Anyone run across a similar situation? Have any ideas???
What happens when you turn the key? - here are some suggestions:

1. Loud clicking from under the hood and cluster lights go dim: bad starter solenoid.
2. Cluster lights stay bright - bad ignition switch, bad starter lock-out relay, or bad neutral safety switch.

Since you say you tried a new relay that would appear to rule that out. When you jumped the relay did you jump straight on to the solenoid terminal or did you still have to use the key in the start position? If you used the key then the ignition switch is probably OK and so is the starter solenoid (unless you went straight on to the starter) but the ignition switch can become intermittently bad (don't I know it!).

That leaves the NSS as a possible cause. That's if you have one - I couldn't see it on the cct diagram in this link: http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1996/S500/SYSTEM WIRING DIAGRAMS/6068.pdf. They are usually on the side of the gearbox but this diagram shows the lock-out relay getting its 0 V connection from the transmission control module. So I guess the module knows whether you're in 'P' or 'N'. Did you try starting in both 'P' and 'N'? So I guess the remaining item is the switch/wiring that tells the control module what gear you're in - I imagine that's in the centre console somewhere.

Mike
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Hey Mike, thanks for the reply. When I turn the key "nothing" happens no click, no noise, lights stay bright and I have even tried it with a battery charger on low just for good measure. I have replaced the starter lock out relay and that is where I jumped the circuit with the key in the run position. I too thought maybe a NSS so I called the dealer a to get a price and was told this model does not use a NSS as the transmission is electronic. So Iam back to square one :( I have tried starting in all gear positions including park,neutral, and drive.....figured it couldn't hurt. I also thought maybe something with the key or alarm but the battery in the remote is strong and I get a green light on the mirror when I hit unlock......however and it just donned on me, the driver door is not unlocking all other doors will unlock just not that one.
 

·
Registered
W220 S320 CDI 2005; W140 S280 1994 (Sold Nov. 2012)
Joined
·
867 Posts
Hey Mike, thanks for the reply. When I turn the key "nothing" happens no click, no noise, lights stay bright and I have even tried it with a battery charger on low just for good measure. I have replaced the starter lock out relay and that is where I jumped the circuit with the key in the run position. I too thought maybe a NSS so I called the dealer a to get a price and was told this model does not use a NSS as the transmission is electronic. So Iam back to square one :( I have tried starting in all gear positions including park,neutral, and drive.....figured it couldn't hurt. I also thought maybe something with the key or alarm but the battery in the remote is strong and I get a green light on the mirror when I hit unlock......however and it just donned on me, the driver door is not unlocking all other doors will unlock just not that one.
So it sounds like your transmission module is not asserting 0 V on pin #5 of the lock-out relay for whatever reason. I guess it could be to do with your central locking problem - if that's a new problem that's also just appeared - otherwise, the transmission range recognition switch on the gear selector or the transmission module (is it fused?). I don't have any diagrams for the transmission wiring so can't 'help' any further.

Mike
 
1 - 4 of 4 Posts
Top