prospective 94 e420 purchase..questions?
 

I looked at a 94 e420 today and have the following questions:

1. Is the wiring harness an issue with the 119 engines and if
so, at what mileage is the typical failure? This car has 40k.

2. The radio works fine on AM and the CD changer works fine,
however the FM will not receive any stations. Any ideas?

3. When locking from the outside with the windows down,
holding key from the right should raise windows and close
roof - it does not do this.


Any help would be greatly appreciated.

Thank you,

Dan

The wiring harnesses on all 1993-1995 cars are bad.

It seems that 90% of the complaints are on E320s, though.

Why? I have no idea. Maybe it's because they sold more. Maybe it's because M104's suffer from head gasket failure, and moving the harness out of the way to change the head gasket causes more of the insulation to fall off, thus causing misfire problems at the injectors.

But, there are also complaints on the M119's, but most of them seem to be on the early 1992-1993 models. You rarely hear or read of complaints on 1994-1995 E420's, but we do know that the harnesses weren't fixed until late 1995. All 1996 and later E320's and 1997 E420's do not suffer from this problem.

We do know that the 5.0 liter M119 in the 500E / E500's from 1992-1994 do go bad, too, and it seems to be at a high rate. One can only guess that it is due to heat.

Everyone seems to say that the new harnesses on six cylinder M104 cars have been updated so that this problem never happens again. Pretty much all techs say that they've never had to replace a harness a second time.

However, Guido, a member here who is a dealer tech, says the replacement harnesses for 500E's / E500's are still bad, and need replacement every 100,000 miles or so. Maybe this is due to the limited number of 500E / E500's sold, so they are still using up the original run of parts.

Since engine wiring harness seems to be such a rare complaint on 1994-1995 E420's, I'd put it low(er) on my list of things to look out for.

I'd say from reading posts that there is a higher failure rate of the throttle actuator on these cars, and that part costs over $1,000.

The a/c evaporator had a high failure rate on early W124 cars, and it is about a $2,000 job to replace, mainly because it is buried behind the dash and taks 16 hours of shop labor. It doesn't seem to happen much on the later cars, say 1992-1995, but you do read about it happening from time to time on this site. I suspect that it is more common on cars in the southeast, where there is a lot of humidity.

The last thing I'd look at on E420's is power steering pump leaks, at the hoses and at the seals. They are about $400 to rebuild, and more to replace. The main reason is labor. There is little room to work around in these cars.

1) The wiring harness issue is not a mileage issue but a time issue. If is hasn't been replaced yet it will need to be.

2) The stereo is probally bad. I don't think it would be worth fixing.
3) That I can't help you with. It works on my car after the key is held in position for a second or two.

Re: prospective 94 e420 purchase..questions?
 

I'd suspect that either there is an internal problem with the radio, or a problem with the antena or a modulator / booster (or whatevery the hell it's called) is bad. It is in the trunk.

I'd recommend posting this problem in the audio section.

However, the original radio's suck, so I'd drop a new one in anyway.

However, the original radio's suck, so I'd drop a new one in anyway.
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You can get a great aftermarekt AM/FM/CD player installed for $250 or less at places like Car Toys, etc. You will have a much better unit than anything that comes from the factory, especially on the older MBs.

Does the trunk lock on your car have the same window up feature as the driver's door lock like my wagon does? If so try the window thing from there - it could eliminate the driver's door lock and internal mechanism as the problem. Do you hear any noise like a hum when you lock the doors? Vacuum problem maybe?

The 420 wiring harness is made of the same flawed material as the 320 but there are two reasons why the 320 is more likely to fail - 1) as Paul mentioned the 320 wiring harness has to be disturbed to fix head gasket problems, and the 420 does not have head gasket problems, and 2) the 320 wiring harness goes all the way to the spark plugs, whereas the 420 harness goes only to the distributor. The 420 has convenential spark plug wires and replacing the spark plugs does require that the wiring harness be disturbed.

Both harnesses fail from both time and heat/usage. That said, a 10 year old harness with 40k is probably going to fail the next time it has to be disturbed. But if the car has been dealer serviced it may have already been replaced, even with the low miles. The dealer service records should show whether it has been replaced. Absent evidence that it has been replaced I would assume about $500 in parts and $200 to $300 in labor the next time it is disturbed for any reason.

The window lock problem I don't think would be expensive - sounds like a fuse or bad connection.

You could always take a look at the wiring harness in the car. If the engine wiring harness is a problem it should show itself right away upon inspection. The wiring insulation would be dry, brittle, cracked, and flaking off. We're curious what you'll find.

Thanks so much for the input. My brother inlaw (who is an auto body tech) works almost exculsivly on Mercedes, has an in at the local dealer , also suggested I run the VIN#. We will do this monday morning. I would really like to keep the factory radio...I like to keep things as original as possible.The owner states this problem showed up after the battery was allowed to discharge.I don't think this is a CODE problem as I believe the radio would be totally inoperative.I believe this car has the Exquisit version radio.Are there any aftermarket radios that will plug directly into the factory wire harness AND operate the factory CD changer?Is the throttle actuator integrated into the throttle body or is it a seperate drive motor mechanically linked to the throttle plate as in my '91 300e? I guess I need to try the LOCK/WINDOWS UP from the trunk lock or passenger lock to isolate this problem.Thanks for all the help! Dan

Dan,

its a great car. Dont let these things scare you. Speaking from experience, I will add my .02. What I would look out for would definetely be the wiring harness. Pull the air cleaner off and check out the wires or have a mechanic do it. You can get the harness from the dealer for around $420, thats what my dealer quoted me. You might be able to find one cheaper, depends on how bad the dealer wants to rip you off. If you have any mechanical inclination, you can do it yourself in under an hour. Just take your time and follow the leads of the old one.

The radio I think alot of people will disagree with what I have to say. I have kept my factory radio. Not only does it look good and is original, but I think it performs perfectly for what I need it to do. I had a replacement faceplate from becker installed, due to bad buttons/lights, etc. They only charge $80. A good deal. Its somewhat difficult to add an aftermarket system to the 400E's. They come standard with the high-perfomance (by mercedes standards at the time) with 10 speakers. It consists of 6 speakers in the rear deck, 2 on the dash, and 2 in the front doors. To add an aftermarket, you have to run alot of new wiring to the head unit from the trunk, for example, an antenna cable. You also have to either bypass the 2 factory amps (1 per side) or wire it special to use them. When the system is all working properly I feel it sounds good. It has good depth. At high volumes, with bass and treble on full, it tends to clip.

The window closure feature I wouldnt tend to worry about. It could be linked to the door handle. Try it on the pass door and/or trunk. You will probably find you will hardly use this feature.

DEFINETELY pay a MB dealer to give it a once over before you buy.

Good luck

Where are the locations on the rear deck.? When looking at the rear deck of my 400E I can see two locations between the headrests and the side of the car. From the trunk I can see two magnets from those locations. Where are the other 2 speakers?

They are under those 2 covers. They have a midrange and also a tweeter packaged in there. They are all within inches of each other. If you take off the cover you will see what I mean.

RE: the window up feature, try turning the key to the 'unlock' side and holding there for a second or two, until the windows start to go down, and THEN turning in the 'lock' direction and holding. Your windows will probably go up then. I believe it's a safety feature to make sure you really want to close the windows.