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Hi there - new to forum! This is related to a 2005 S430 (W220) I'm stuck trying to troubleshoot this issue. Current problem: Doors will not lock.
Hear solenoid in PSE unit, but does not lock any door. Relevant other info: Central unlock works, remote fob works, trunk works.
Question: What could be causing this? A leak within the line(s) for this? Which connection is for the door locks - does someone have a link to which air connection supplies what system. For instance, I'm guessing HECK is for trunk for example. What is the way to test the line? I know it works on both pressure and vacuum. For instance, can you disconnect the relevant air line and then either apply pressure (how much) or vacuum, to see if it either a) operates the doors (so perhaps solenoid valve in PSE is somehow faulty) or b) the air pressure/vacuum changes fairly quickly indicating a leak?
Backstory: There's a lot more to what I've done than above, so here's the history.
All of a sudden I had failure of PSE system, as no doors would lock, no headrest drops, no trunk opening. Here's kind of what I did from memory.
I checked fuse (F62, 20 A in rear under seat fuse box), it was blown.
Replaced with new fuse. Fuse blew again very quickly.
Removed PSE, and disassembled, removed pump. Pump seized, charring/burn colour by brush holder. Power wires to pump, touching each other, with insulation partially melted. So assuming enough high current to melt insulation before fuse blew.
Sourced a used pump. Tested in direct on battery, works.
Installed new pump - fuse blew again! :-(
Assumed, there is likely a further insulation meltdown in the power wire to pump somewhere between fuse and pump.
Removed rear seat, seat back, trunk liner as I wanted to trace the wire (Red w/ white) to see if can locate a ground fault/short.
Could not locate any false ground. Assumed perhaps that in loosening the rear SAM or the PSE unit, somehow wires relocated to not cause the ground fault. Manipulated the wires with a constant audible continuity tester in hopes I can verify I have a ground fault somewhere in the wire. Was never able to generate that problem.
Connected fuse back in, shows the +13 V at the pump. Connect pump, it runs fine. (everything is in parts at this time)
I put everything together in piece wise fashion and testing it at each step to see if I generate a false ground or that I still have the 13 V (still suspecting there must be a wiring issue somewhere - but the wires run forward all in part of the big loom). All good.
I get all the air lines hooked up and test it. Pump runs for some time then fuse blows again! Uggh.
I do some more looking for a ground fault on that wire - still nothing (I verified I have a good ground, as I test it for voltage on same screw if I put fuse in and that's good).
Upon not finding anything, I replace fuse and now the rear headrest button worked and the trunk kind of worked! Like, upon closing it spat out the handle, but would not retract it. So thought perhaps a leak in that unit. Removed trunk liner and see if I can get a closer look. Or perhaps hear hissing from a leak.
Now I have a working trunk release, including the handle that comes out and retracts after closing. Also, if I manually push down the door locks, the dash button (or key fob) will unlock the doors. But the doors will NOT push down. Manually pushing them down, they all seem stiff somewhat. However, the resistance is the same for unlocking.
Update:
I've noticed the pump seems to run longer whenever it is called for (e.g. pressing unlock button, etc.). The latest is the fuse is blown again.
So either,
a) for some reason the motor is drawing too much current (I don't have a multimeter that has 20A+ capacity to check the draw) or
b) there is an intermittent short somewhere in the wire from the prior issue above (possibly other melted insulation)
Or, is there another possible issue that I'm not aware of? Like, could there be an intermittent fault with the circuitry of the PSE (solenoids, etc.)? I'm not a mechanic and I'm not strong in electrical matters, so I'm at a loss. Any help would be greatly appreciated.
Update #2:
I've now spliced in a replacement wire from the fuse block, wiring up an external fuse, to the group plug on the PSE, to completely remove the existing power wire from the circuit (per theory "b" above).
The pump works, pumps for fair bit of time. It doesn't seem to get proper vacuum, as now the controls are still not working fully (like when I manually lock the trunk latch it doesn't unlock it when pushing the button, and the pull down handle from outside does not come out (Retractable Trunk Handle), but it does the first part where it moves the cover down to allow it to come out, then stays there).
While I was inside testing unlock button, etc. I could hear the pump working. It shut off after a while then immediately kicked in again (vacuum leak?), it may have done this more than once, then it seemed to be working hard to finish it's cycle. Slowing down, working ever harder and slower, like it just can't quite get there and then watched the fuse blow. So, it seems as it slows down, works harder, you can exceed the fused amperage.
So, at this point now I'm 100% certain, it is not the existing wire supply.
My next thought is to take the PSE apart, and adjust the pressure switch (per PSE Pressure Switch Adjustment) - although if it is too high, the controls should still be working, which they are not (in contrast to earlier where they HAD appeared to work).
QUESTION: Is there a method on how to check individual air lines. Specifications of pressures (both + / -) required, etc?
Setup for bypassing power wire to PSE from fuse block.
Last edited by trialsntrib; Jun 29, 2022 at 09:09 PM.
Reason: new info.
Well, I've located this resource: PSE Pump System so I have more information.
I've verified the resistances on all the coils, my meter shows them as 34.5, 34.7, 34.7, 34.7, 34.6, 34.1, 34.8, 34.7, 34.5, 34.5. So, they all check out.
I've been able to test some of the air lines, by simply using my mouth to create suction (successfully dropped the rear headrests, for example). But do not have a manual/hand vacuum pump to test better.
When I wrote earlier that I installed a new pump, that is not correct, it was a used pump sourced of Amazon, even though it had been indicated as new. However, the pump ran fine,. But perhaps the pump itself is not in best shape
Yikes, in all this analysis, I failed to see slight bubbling of the base plate as described in link in this post. I've not yet been able to test, but certainly that is likely the issue.
I’m sure you checked for leaks at the door actuators correct ?
BTW I posted a question about setting the PSE pressure . There are two ports looking down into the unit . Mine has the white dial / screw in the near side to the coils . Did you figure out if it was clockwise or counter clockwise to set pressure ?
Thanks !
I’m sure you checked for leaks at the door actuators correct ?
BTW I posted a question about setting the PSE pressure . There are two ports looking down into the unit . Mine has the white dial / screw in the near side to the coils . Did you figure out if it was clockwise or counter clockwise to set pressure ?
Thanks !
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