Jason Riha

I really screwed up this time.. after research I found out how touchy the electrical systems are on these guys and feel really stupid right now. I bought running lights recently for my lower bumper. On the packaging it said connect to any 12v source and to test with the car running. I didn't have proper tools so I opted for a random wire running to the fan. Obviously a dumb choice because for one it didn't light up.. two.. my fan runs super high now and the "ac off" red light is stuck on.

I have learned my lesson so please don't be cruel.. should I just suck it up and wind up paying the dealership to star test and fix it or has anyone else dealt with this?

I have a 2003 s430 I live in Corpus Christi, TX.

Jason Riha

When I had my Ford I could caveman anything to make it work I understand now how easy it is to screw up a Merc.. I noticed the electrical tape I used to cover the now naked wires was not very well wrapped so I did another tape session

Jason Riha

Didn't help 😠

engindin

i thought I am the one who do such mistakes, anyhow that's the way we learn new things. Unfortunately I don't have experience in this case but I have running w220 and a multimeter. I can measure any value if you need in wire/fuse etc.


It can be like this, when you connect your running lights to your fan wire, it pulled too many current and blow a fuse or sensor, and because of w220s are engineered awesome, to be in safe side it runs the fan anytime.


start checking fuses from passenger side fuse box, f33 to f48


When you get tired finding the problem, can go anytime to dealership

Jason Riha

Thanks for the reply.. I will check the fuses.. assuming the fuse panel inside below the rear passenger seat?

wallyp

There are several fuse boxes on the W220, and fuse locations and values vary by both model and year. Two large plastic boxes at the rear corners of the engine compartment, one at the right end of the dash under the snap-off cover, the one under the right rear seat, some fuses under the trunk lining, some under the carpet...

If you look at the encyclopedia at the top of the page "...start here." you will find a post with a link to fuse locations to all years. It is not very likely that replacing a fuse will help you in this case.

It will be helpful if you edit your info to give the model year, and your location. There are Forum members who have a STAR/DAS system, and one of them might be willing to meet you and hook up their system to your car.

kraut56

you may have caused grief to the ac controller software.
Check out AF83.40-P-2400A in WIS; to clear the red AC light in the button and to have the AC come on again the controller must be cleared using DAS.

Worked on my car just fine.

Good luck!

Jason Riha

Thanks for the advice and reply sir.. I updated with my year/model/location. I posted on a local mechanics page to see about any local mechanics that may have a star diagnostic beside the only stealership in town (which I dread taking her in to).

Jason Riha

Could this also cause the radiator fan to constantly blow on high?

kraut56

don't really know, but I do know that the AC controller inputs into the engine ECU to control fan speed.

BTW:the AF mentioned before says "software error in ac control module" without indicating a DTC"

Jason Riha

Thanks.. yes, this makes sense as to why it runs non stop.. I read that mercedes naturally keeps the fan at full blast when anything having to do with it has a malfunction. I found a local mechanic with descent prices that has STAR.. Trying to set up an appointment right now.

Do you know of an ECU reset would fix anything or possibly make something worse?

tusabes

It might fix it and it shouldn't make it worse

kraut56

No, not an engine ECU reset; the AC controller needs to be cleared of an internal non-annunciated fault memory.

Needs following steps:

1) do quick test and clear all faults

then
2) go into control units
3) air conditioning

then goto sub-menues:

4) automatic air conditioning
5) troubleshooting over complaints or symptoms
6) automatic air conditioning does not cool
7) delete fault memory

May now require another quick test and DTC code clearing.

Hope your guy knows how to do all that.

Good luck!