My 99 slk 230 has recently taken to three quirky behaviors.. First the interior overhead light started acting up (coming on and off for no reason) at which time it started to indicate an exterior lamp fault (all of which are fine). The second behavior started about a week later whereby the interior trunk light would flash on and off. I then noted that the alarm would sound/ head lights flash, when no one was near the vehicle.

I am not certain as to whether these are related? The dealer is happy to quote a sizeable estimate to initiate a fishing expedition but first I thought that I would check with the experts here.

I suspect that perhaps the trunk sensor has gone wonky, but wonder if this sounds familiar to anyone?

Thoughts

With thanks

 

welcome rph ottawa

about the alarm, it can be a bad backup battery on the alarm system.
the lamp, we got member who have similar problem and found out that the bad door switch is doing the tricky flash.

is there any way where you can take the car for fault code diagnosis? you can get near the problem quickly but just making a quick scan test.

 

I agree with Sleepwalker regarding the door switch setting and the possibility of the back up battery.
However the bulb warning light suggests that it is either the PSE unit itself or wiring connections to it.
The PSE is situated in the RHS underfloor of the trunck in a foam bundle. It is multifunction and besides operating the pneumatic door locks it accepts signals from the door switches and other sensors inc bulb warning for the rear lights and uses them to control the Interior light, Security system and YES the bulb warning via another module situated in the enginebay.
Although the door pneumatics are in the same PSE unit they operate independently of the control circuitry.
My own experience suggests water ingress / condensation into the PSE module from storing eg wet roof in trunk.
Disconnect the multi pin plugs and look VERY carefully for signs of blueish corrosion.
A fault scan is unlikely to give you much better info on whats wrong than the observations you have already witnessed and I suggest the dealer will just suggest the PSE after charging you circa 30GBP+
A replacement PSE is about 250GBP in the UK. Even with electronic skills it is unlikely that the PSE can be repaired if the circuitboard has corrosion on it.
Stuart

 

Thanks Sleepwalker and snanceki,

I appreciate your direction and will start from there. I will let you know how it goes.

Thank you again

 

hi guey,

i just had a tour around the lower boot, and indeed there is corrosion on one of the tree electical connectors (the one with very small pins.

pardon the stupid questions... but
1- how does one separate the 3 pneumatic lines from the unit?[>:]
2- is there any point to investigating the replacement of that corroded pin and socket?
3-you mentioned a circuit board... i assume inside the unit... should i be looking for corrosion on the board
4- shall i just kiss a thousand $ good bye?

thanks again

randy
sweating my **** off in 30C temparatures, in canada in the boot of my car

 

Sorry, one last question...

It would appear as if one of the pins on the white connector has rotted and in removing it for inspection.... I am now unable to lock the vehicle.

It is possible to lock the driver door, but is there an alternative way to lock the boot?

Thank you again for all your assistance

randy

 

use mechanical key

 

I have just gone through the corroded PSE bit, the bill came to just under £500, the problem is wide spread and should have been a recall as lots of SLKs have had the same fault, later models have had the PSE turned upside down to stop water ingress, you can not do this with earlier cars because the cables are too short to allow the PSE to be turned over.. One point you must protect the PSE the popular method is wrapping it in a plastic bag then taping the bag closed around the cables. The water can come from many places but main source is running down the cables from the car/roof seal from mainly high power washing/heavy rain or leaves blocking the small drain tubes. Be wary of secondhand PSEs because of the many types available and programming needs.

gary

 

hi guys,

thanks for all your comments, one final question...

does this pse unit also control parking lights and fog lights.

i am ashamed to say that i have been lax in replacing the unit due to cost, and the fact that it was only a minor inconvenience to have to lock the doors with the physical key... however the gremlins are now a little too much as the lights are now coming and going at their leisure.

any assistance in determining whether these lights might also be connected to the pse would be greatly appreciated.

thanks

 

no