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New Owner w/ 2 Strange Problems; Central Lock & Radio

1K views 14 replies 6 participants last post by  1994 S500 
#1 ·
Howdy all!

Recently bought a somewhat neglected 1994 S500 Sedan.

Unfortunately, two strange problems:

1:

The power door locks don’t work either via the door lock switch on the center dash or via the key when turning to lock the doors; the red light on the door handle does blink however. What’s strange is that when I either press the lock or unlock switch on the center dash, the overhead interior lights flash on and off once and I hear the pump in the trunk activate. Also, the trunk handle doesn’t pop out and the rear parking assist masts that flank either side of the trunk are partially raised and don’t lower. All doors soft close shut with no problem.

I pulled all fuses at the right interior of the trunk, waited and replaced in hope to reset the system, but no luck. What in the world can the door lock switch have to do with the overhead lights!? :(

2:

When powering on the radio, there is a crackling / static-like sound that comes through the speakers, which I believe continues for a short time even after the telescoping antenna is finished extending. Note, not 100% sure, but believe most or all of the crackling sound is actually coming solely from the center speaker behind the rearview mirror. Almost sounds as if sparking from behind the dash, but no smoke or burnt smell.

Thanking you in advance!

Matthew
 
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#2 ·
Your locking pump is under the rear seat, the motor has probably failed, this can also upset the boot handles etc.

Hard one re the lights, could be poor pin switch in A pillar.
 
#4 ·
Your locking pump is under the rear seat, the motor has probably failed, this can also upset the boot handles etc.
First problem is definitely the PSE pump under the back seat. It's also connected to the dome lights; I had the exact same thing happen (press the unlock on the console and it flashes the dome lights). Replaced the pump and it all went back to normal. Pumps can be either repaired or replaced, not a big deal.
Thank you both! :thumbsup:

I disconnected the battery, let the car sit and reattached, and the door locks, trunk lid handle and front dome lights were working as should again! What a great feeling. Unfortunately, after a couple of rounds of shutting down, getting out, getting back in, starting back up, etc.; wasn't working again! Sad. :(

I took a closer look at the fuse box at the right of the trunk and see that one of the fuses controls both the door locks and the dome lights. Anyway, I pulled all fuses for the door locks and replaced, which didn't help. I've since purchased new 20A fuses, but haven't gotten to trying them yet.

I've also pulled the rear bench seat and see that the pump seems to be new - the newer style pump with the splitters - not the one with the adapter that connects up top - which I believe to be the older style pump. I don't see why the pump should go bad. How can I figure out if it's actually the pump or something else that's wrong? Anything I can do to reset it for good?

I'm now faced with another problem, which I really need help with. My driver's door lock plunger doesn't go down and the door doesn't lock thereby, which means I'm now not able to use the car, as I can't leave it with it's door unlocked when parked. The other door locks work if I push them down. Can someone please help with this as well? Could it be that there's pressure in the line and I should disconnect any particular line that's routed back to the pump?

Last, can any of these problems be related to the engine wiring harness? I'm understand it had been replaced.
 
#3 ·
First problem is definitely the PSE pump under the back seat. It's also connected to the dome lights; I had the exact same thing happen (press the unlock on the console and it flashes the dome lights). Replaced the pump and it all went back to normal. Pumps can be either repaired or replaced, not a big deal.

Second one sounds like your nondirectional tweeter blew or is on the verge of blowing. I'd listen very closely to hear whether it actually continued functioning after the scratching/static went away. It could also be some interference or bad wiring, but that can be hard to track down. The tweeter itself is easy enough to replace if necessary, but that may not solve the problem if it's a wiring issue.
 
#5 ·
Engine wiring harness has nothing to do with this in the slightest. It's the engine after all! :p

Regardless of it being a newer pump or not, it's still nearly 20+ years old. It's going to wear out eventually.

The PSE pump uses a combination of vacuum and pressure to actuate items. It's rare for there to be a leak on the lines, unless someone has fussed about them. For example your drivers door not going down, that item uses both vacuum and pressure to be actuated by the PSE pump. All of your issues can be traced to the PSE pump being faulty somehow. Outside of using an SDS to diagnose it, there isn't really anything you can do, outside of replacing or repairing it.

Also on your speaks, I have an alternative idea as to the problem. Your Bose amplifier has old, dried out capacitors on the tweeter channel and will need to be rebuilt. I have much of the same kind of issue, but on a different speaker. It doesn't happen immediately, but eventually it happens. I've traced this to the amplifier needing a rebuild.
 
#6 ·
Thanks as well!

More specific question regarding the driver's door plunger not going down...

Because I'm not able to push it down by hand or with the key, does it mean there's something wrong with the door / lock / actuator - or, can it still solely be a problem with the pneumatic line / pump?
 
#7 · (Edited)
I would say yes, there may be something wrong inside there. When I was having my PSE pump repaired, I could still lock and unlock my driver's door without the PSE pump even in the car. You still have mechanical parts for that door lock, along with the actuator, and it's these mechanical parts I suspect are preventing the door not locking. I would say this is a separate problem from your PSE pump issue.
 
#8 ·
the door lock is pretty complex system in terms of mechanic. it seems something is blocked. you must get access to it and observe it. after you will understand how it works you can repair it maybe. or maybe levers connected to the lock are blocked which would be best and cheapest option for you.
 
#9 ·
I am SO UPSET. Just damaged the PSE pump!

When removing one of the rubber lines form the top of the pump, the nipple broke off!

SO UPSET. Photo attached.

Any advice on what to do now and how to remove the rest of the lines without further damage.

So not good. :(
 

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#12 ·
Thanks. Any thoughts on how to remove the other lines without further similar damage? Any technique to employ?

I sort of have the same problem with my car's locking/unlocking. But am able lock/unlock ok by using the plungers by hand. The insert key only works on the passenger door. In your case, It does seem like the problem is with that door's locking system.
:(
 
#13 ·
just think about what happens when you put the line ON the pump. consider what happens. So when you are in a position to remove the line OFF of the pump you must do something in an opposite way :). I do not see any connector (line) on your picture so it is hard to say. I use a big flat screwdriver on my pump and pry the connector (upwards) slowly over its circumference let's say every 90 degrees.
 
#15 ·
Hi all, just wanted to update everyone with what I did to get the lines off...

Used a blade to slice the rubber lines horizontally immediately above the nipple and then sliced what was left surrounding the nipple vertically. Even after only a small piece of rubber was left surrounding the nipple, it was still a pain to get off!

Wish I did this before, without pulling on the lines and damaging one of the nipples. :(
 
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