1995 E300D looking for opinions on window motion control - PeachParts Mercedes-Benz Forum

Texasgeezer · #1 07-19-2018, 09:44 AM

A few months ago I pulled the front door panels & cleaned & lubed the slide area & gear on the window regulator. I cleaned ( didn't burnish ) the small relay contacts mounted on the convenience module. I replaced the associated relay behind the fuse panel with a Mercedes provided part.

Rear windows have always worked.

Recently both front windows have quit working again. The convenience relays are operating & 'sparking' a little when window switch is released. I've ordered new relays to replace the ones on the convenience module, but I'm concerned that motor current is possibly excessive & will burn the new contacts fairly quickly.

New motors appear to not be available from Bosch & probably not from Mercedes ( they want a core charge ).

I hate to start throwing money at it & buying questionable rebuilt motors.

If it was you what would you do?

Motors - pull & have a local shop try to improve them? Buy a rebuilt one? If so, from which company. Or?

Window rubber parts - buy new ones from Mercedes & hope they're still pliable? Use high viscosity silicon oil on the rubber parts that contact the glass & live with the possible streaking?

convenience module improvement - any ideas?

Other suggestions?

Maxbumpo · #2 07-20-2018, 02:24 PM

Have you tried cleaning the window switches in the center console? They are notorious for getting dirty inside. Carefully pry out the top rocker switch while working inside a plastic bag to contain all the parts, clean up the inside with De-Ox-It, and they will be good as new.

Diseasel300 · #3 07-20-2018, 03:16 PM

Make sure the window moves freely in its track. Disconnect it from the regulator and move it up and down by hand, it should be EFFORTLESS. If it is dragging or binding up, the motor current will be excessive as the motor stalls.

Texasgeezer · #4 07-20-2018, 04:00 PM

Thanks for the replies

My console switches are good. The problem appears to be excessive current burning the relay contacts for the front windows. The convenience module below the rear seat has 8 small relays. Four left ones are for the front. Four right ones for the rear windows. Rear windows always work.

Each of the four relays for the front will energize when the console switches are pressed. Just not enough ooomph at the motor to cause the motor to turn. I fixed it before by cleaning the contacts with contact spray.

I want to fix it so the front windows work reliably. If I replaced the related parts with new Mercedes parts the cost would approach $2,000 & that probably has rebuilt motors from Mercedes not new ones.

I do expect the glass is dragging since the rubber parts are 23 years old. The motor brushes may not be making good contact due to positional burning. I do not believe it is regulator issues. They looked good when I cleaned off the old grease and applied new grease a few months ago.

I bought a used functional convenience module from a Dallas salvage yard. It works the same as mine. Relays energize but no front window motion.

I'm hoping to get some tips on what to do about the motors and window rubber channels and lower wipes. I'm concerned about new rubber parts being old stock and might also not be flexible. Hoping others have fought this problem and might give me some input on what made their windows be reliable. I've read that silicone oil in the window channels has fixed the problem for others. I plan to have new tint installed soon and haven't wanted to possibly mess up that with silicone streaking on the glass.

Today is approaching 108, so I get up early and work on the car til it warms up too much.

Probably will take me several days if not a few weeks to sort this one out.

Does anyone have any experience with A1-cardone or other motor rebuilders.

Diseasel300 · #5 07-20-2018, 07:52 PM

Buying a rebuilt motor to replace a motor that's currently operable will not solve the problem. Unless the armature is burned up (extremely unlikely), the current draw will be a function of the load on the motor. Fix the drag problem, let the motor do its thing. A "rebuilt" motor will very likely be worse quality than what you're dealing with right now, assuming it even works out of the box (A1-Cardone).

Chris W. · #6 07-21-2018, 01:25 PM

I had good luck with a chicom motor-regulator assembly off eBay, like this one:

https://www.ebay.com/itm/Power-Window-Regulator-w-Motor-Rear-Driver-Side-For-Mercedes-W124-1247300346/281724115250?epid=10007491781&hash=item419810d932%3Ag%3A67sAAOSwv%7E1aDx8Q&_sacat=0&_nkw=w124+window+regulator&_from=R40&rt=nc&_trksid=p2380057.m570.l1313.TR1.TRC0.A0.H0.Xw124+window+regulator.TRS0.TSS0

I know this is a rear window, but they have similar front units too. Only changed this, not anything to do with the switches or relays. Gave good service for several more years - sold the car with it working fine.

Rgds,
Chris W. ex '95 E300D, 467K when sold

Texasgeezer · #7 07-25-2018, 05:37 PM

Thanks for the replies. Unreal how cheap chinese parts can be.

I agree I need to reduce current load on motor to protect control board relays. I've ordered new front window runs and the inside & outside glass 'wipes'. Runs have to ship from Germany. Hopefully they will be fairly easy to install.

My ordered relays have arrived. I ordered Siemens and Tyco to compare the quality. Siemens visually look better but if one has bigger contact points I'll probably use that brand. There are 7 solder points on each relay. I've checked on soldering irons and solder suckers & will order those tomorrow. I plan to replace the four relays that control the front windows. They are mounted on the convenience/comfort module that resides below the rear seat. Pictures show the Tyco relay as delivered.

Texasgeezer · #8 07-26-2018, 12:05 PM

I'm researching soldering irons/stations. Anyone have an opinion on one with auto temperature control. Also opinion on solder suckers.

I'm leaning towards the Hakko FX-600 or FX-888D.

My main concern about changing the relays is the relay copper construction might suck up a lot of the heat from the soldering iron and cause difficulties leading to damage of the circuit board.

Diseasel300 · #9 07-26-2018, 08:21 PM

Are you planning on doing a lot of soldering or reworking a ton of circuit boards professionally? If not, shelling out big bucks for a soldering iron isn't a wise investment. You want something quality, with interchangeable tips, and 40W element. While it isn't anything fancy, the Weller WLC100 from Home Depot is a decent setup. I have one here at the house that I use when I'm too lazy to drag something to work to use the expensive soldering stations.

Skip the solder sucker too. Invest in some solder wick. The suckers suck. And not in the way you want them to.