RLich8

Hi guys, I just took over an 05 SL500 - silver exterior/black interior, and 30k miles. Went through and did a bunch of little maintenance things like control arms, motor mounts, replaced an ABC line, flushed ABC, trunk struts, new left and right front wheel hubs, simple oil change, etc. It is not an abused car, but a rather clean and original one.

The car runs great, no malfunctions at all. The two remaining issues:

1. The climate control seems to have a mind of it's own. The fan control doesn't respond up or down a lot, and says Auto almost all the time. I can get the car to heat and cool fine if I push the temperature control far enough to heat or cool but overall, it lacks driver input.

2. The radio sounds like it has no oomph at all. The radio on a ten year old Honda civic is better. There is no bass, treble is ok. I remember the stock radio on these cars being very good (my father had this car in 2003) and sounding pretty nice. Also, the reception for FM seems very bad.

Any ideas?

I look forward to becoming part of this community. I love the car - rode in one in my teen years - and I'm excited to now own one.

Thanks guys
Royal

Aussiesuede

Regarding the radio, I'd suggest pulling it out to see if there are signs that an aftermarket unit had been previously installed and then removed. When an aftermarket unit is installed, you have to work around the original fiber optic system. Often things don't get reconnected to stock upon reinstallation of the factory unit because of a myriad of potential errors. The stereo systems on this era of R230 are very proprietary, an a proper reconnection can be a challenge without knowledge of how the original system operates and some will stop investigation once they successfully get 'sound', especially when a vehicle is being prepared for resale. Once you've confirmed, then come back and we can start helping you troubleshoot the system. You might get lucky and it's just that the fiber optic Amp hasn't been reconnected. For your sake, I hope that's the case, since troubleshooting the system can be a pain.

Re: the Climate Control, I's suggest investing the $125 in an iCarSoft MBII scanner, since it'll read the climate control errors and point you in the right direction. The scanner will prove invaluable in diagnosing other systems as weel (Brakes,ABC, SAM modules, etc)

RLich8

Thanks - I'll check out the scanner - may have the ability to borrow one.

I did find this unconnected inside of the fuse box behind the passenger seat - any clue if this might be a contributing factor? Or is this perhaps just part of the wiring loom for some option that my car does not have...?

Nosmo SL55

With the climate control, push the button/knob where "Auto" is lit up and it will pop out and you will be able to manually control the system.

RLich8

Unfortunately, this isn't my issue. It is irresponsive to most input even when it is popped out. Most of the time, when popped out, it stays on Auto. Once in a while you can coax it to work, but it is absolutely not working.

Aussiesuede

Does the SOS lamp just above your rear-view mirror blink when pressed? I can't confirm without seeing the pin faces to the plug, but it looks similar to the Tele-Aid plug. The TeleAid system is now obsolete, and it is known to malfunction, causing the Tele-Aid unit too continuously attempt to make a phone call, thus resulting in overnight battery drains. Simple remedy is to unplug the TeleAid unit the which resides near that plug you're holding beneath the rear storage cubby. The original stereo amp also resides beneath those cubbies (Passenger side), as does one of the diversity antenna control units (don't know the official name?)

Aussiesuede

Ahhh. This explains your scenario in more detail. When I first acquired my R230, the "Fan Speed" control knob was erratic. Sometimes if it were turned slowly enough, you could acquire the fan speed you were trying for, but more often than not, it just sped up to full, nothing, or somewhere in between - all of it's own choosing. Upon inquiry, most suggested I needed a new climate control unit. Being someone who typically see's these instances from the point of view of " It it's already broken, then I can't very well break it - can I?" So for me, that meant opening up the unit to see if there was anything I could notice that was amiss. In my case it turned out to be pretty simple - dirt, dust, and hair was visibly noticable on the stalk of the Fan speed Knob. About 5 minutes with some rubbing alcohol and a Q-Tip was all it took to regain control of my Fan Speed knob. So wait for some suggestions from others 1st, and if th common suggestion turns out to be "anew Climate Control Module, then you can decide if the Alcohol + Q-Tip method seems to be a potentially viable one for you.

RLich8

GREAT post, thank you... I was thinking, "the contacts inside this thing might just be dirty, maybe it needs a cleaning." Glad I was able to corroborate my suspicion... I'll go a few more days to see what people have to say but might end up going this route. All of the other switches/dials work just fine, by the way. It is literally only the fan speed control that is screwy. Hopefully I won't have to spend $700 on a new control unit.

RLich8

Just an update - Aussiesuede, I think you were onto it. This morning when I hopped in the car, I lightly turned it left to right about 50 times and it appears to be functioning just fine now. If it occurs again, I'll remove the unit and clean it out - surely there was nothing more than a little dust/hair/debris affecting the use of the contacts.

Now just to solve the radio problem.

TheSaint

I am sure the problem with the fan speed control is dust in the potiometer. If the fan knob is in postion 1 and you just touch it the fan motor might go up to 5?

It is almost like an old stereo when you adjust the sound louder or lower you hear that "dusty" sound.

I am pretty sure that the AC/blower have been in position AUTO most of the time and if you start to use the blower motor manually that might help

You can also clean it using electro cleaner but be careful when doing that

Aussiesuede

Excellent! I love it when when we're able to cheat the Stealership lords! lol Now fingers crossed that that stereo Amp is simply unplugged!

RLich8

I'm thinking the subwoofer might be bad or unplugged -- the mids and highs are good but the system lacks bass. And I know they aren't super bass heavy systems, but there's nothing... I can't feel anything when I put my hand underneath the glove box, so I am betting it's bad.