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Serg is right .5V is high for a regulated output.

The radio and cruise may be related to the actuator fix. Quick and dirty - the radio can have the speed send input nixed on the radio connector. Cruise could be retired. If it's a simple connector issue or a cold solder joint it may be worth a revisit. One concern would be over working the thing and creating a total failure. Plus, its a great excuse to upgrade the stereo. The window deal is not related.

The actuator internally uses a variable resistance strip and wiper contacts to tell the brain throttle position. It is fine as the system goes nutty when they fail. Not serviceable and when worn out, the actuator is a write-off. They also have bi-metallic coils for temperature variable needs. I would not explore the internals as cannot be effected from your wiring job.

Evaluate the probable life left in the car and consider a basic revisit on the connector then quiting while ahead. I know it's hard to stop poking. You still have an 80 percent on the actuator report card.
 

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Discussion Starter #22
Sergio

They want $75.00. I figure that thats a little high, but at this point, I pay it. I'm also getting new low voltage connectors for the coil as the rear one doesn't fit as tightly as I would like. I figure I will just replace all three. MB of Lancaster is charging $11 each for the caps and $3.00 each for the contacts.

Greg
 

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Discussion Starter #23
Thanks again for all of the input. I replaced the voltage regulator and the low voltage connectors on the primary side of the coils yesterday. Voltage is now 14.11 at idle and 14.13 at 2k RPM. The new voltage regulator solved my cruise control and auto down problem on the windows as well! I am now a very happy camper:)

Thanks again
Greg
 

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Discussion Starter #24
I forgot to mention that the radio's erratic behavior has settled down as well. I would still consider replacing it if I could find a replacement that didn't have bright flashing lights or look like it belongs in a kiddie car.

Greg
 

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I cut a slit ~3" from where the harness enters the actuator and there is flaky insulation and bare wire showing. I will pull it off this weekend and rewire it. In addition I will plan on cleaning the throttle body as well.

Greg
Greg,

Did you suceed in rewiring your throttle? I was happy now that I pass the aircare. I still have occasional surge problem when on stop. I am assuming that it might be a MAF.
Raul
 

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Discussion Starter #26
Hi Raul

Yes, I was successful in rewiring my throttle actuator. Thanks for the pointers along the way. After i got the idle squared away, I ran into some over voltage problems due to a bad voltage regulator, but now my car is running excellent. I need to get it inspected and put some nuw rubber on it and i will be good to go, hopefully for some time.

Greg
 

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I do not mean to hijack the thread, but was wondering if someone may think that the voltage regulator may be my issue. My cruise does not work. It used to work intermittently and I resoldered the amp and it stopped working. Since I have tried two replacement amps and after the CEL came on for the throttle actuator, I had an INDY replace it with a tested used actuator. The cruise still does not work and I even replaced the brake switch and checked the tire size and pressure. Would the MAF cause the cruise to stop working? I think my MAF is working alright.

If it is the voltage regulator, where is it located and how can I test?

Thanks,

Hank
 

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Discussion Starter #28
hank3d

I don't think the MAF sensor could cause the problems with the cruise control, but a bad OVP relay could cause it. The OVP ( over voltage protection) relay is behind the battery and has a fuse on top. They are known to fail over time so if yours is original you might want to replace it.

The voltage regulator is on the back of the alternator. You have to drop the underbonnet and remove the plastic cover on the end of the alternator. Remove the two retention screws and put in a new one. You can check the voltage regulator by checking the battery voltage at idle and at ~2500rpm. The voltage should not vary by more than a few tenths of a volt. If it does, the regulator is bad.

Greg
 

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hank3d

I don't think the MAF sensor could cause the problems with the cruise control, but a bad OVP relay could cause it. The OVP ( over voltage protection) relay is behind the battery and has a fuse on top. They are known to fail over time so if yours is original you might want to replace it.

The voltage regulator is on the back of the alternator. You have to drop the underbonnet and remove the plastic cover on the end of the alternator. Remove the two retention screws and put in a new one. You can check the voltage regulator by checking the battery voltage at idle and at ~2500rpm. The voltage should not vary by more than a few tenths of a volt. If it does, the regulator is bad.

Greg
I replaced the regulator and the battery tested fine. I think that the only thing left is the switch itself. on the W202, is there a CC Actuator (not talking about the throttle actuator) I searched and could not find the part.
 

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Discussion Starter #30
Hank3D

The cc actuator and the throttle actuator are the same part. Did you pull the codes yet? If you pull them from pins 3, 11, and 16 you should get a pretty good picture of whats happening with your cruise control.

Greg
 

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Hank3D

The cc actuator and the throttle actuator are the same part. Did you pull the codes yet? If you pull them from pins 3, 11, and 16 you should get a pretty good picture of whats happening with your cruise control.

Greg
Do you mean the OBD codes? That is the only scanner I have and there are no stored codes. When my Indy mechanic scanned the car, he stated that it was the throttle actuator and we replaced it and it still does not work.
 

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Discussion Starter #32
Hank3rd

The codes i'm talking about are the ones from the 16 pin diagnostic port next to the battery. If your indy pulled the codes and replaced the actuator, I'm not sure what else to tell you to check. The CC signal gets compared and modified by a lot of sensors, including the fuel pump cutoff. Maybe someone more knowledable can chime in.

Greg
 

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Does anyone have:

1. The MB part number for the connector on the end of the harness going to the ETA?

2. A recommendation on what wire to buy to re-wire the ETA harness, and where to buy it from?
 

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Discussion Starter #34
The DIY sticky is an excellent idea! I just stumbled across it. I would like to add a further comment regarding rebuilding your wiring harness. Do not simply splice into the existing harness inside the engine bay (300E and E320) even if the insulation looks good near the battery. You may wind up with an electrical short inside the computer connector housing and have to redo the harness (ask me how I know). If you rebuild a harness on a 300 series it is best to rewire all the way to the computer connector. You will have to reuse the old pin body as they are not available, but the pin body housing is available from MB for under $20.00 US.

Greg
 

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Kudos to all who contributed to this thread.

There's a helluva lot of info here about the "ins and outs" of several key 94 E320 trouble spots....engine wiring harness, the TA unit, and good troubleshooting info on the symptoms of voltage regulator troubles. (Not to mention the excellent Wiki DIY link on Engine Harness Replacement. Both now bookmarked.)

My coupe has yet to experience any of these woes in its 104K odo life but, as well chronicled in many forums, they are right up there with death and taxes as eventual, if not imminent, events.

Thanks.
 

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GDC (or anyone else),

When you rebuilt the engine harness, how did you replace the ignition coil wires and connectors (3) which go through a rubber mold? I am thinking of cutting the rubber open and gluing it shut w/ new wires in place. Is this how you did it? And how to open those connectors to solder in new wires?

Also the 6 connectors for each of the cylinders along the drivers side of the engine? It seems I should be able to pull the two wires at each of these connectors to put in new wire ends?? Correct?

The big black connector at the ecu seems to have some epoxy material sealing it which I am trying to break through to remove the white pin body so I can solder new wires in. If I am successful, I should be able to reuse the connector. Did anyone reuse this black connector outer body?

My old harness is out and am looking to rebuild it -- there are some connectors which don't seem that they can be opened. Do I have to cut open these? And glue them back or something?

Great to read that some have rebuilt these harnesses for fraction of the cost and I am sure to a quality even better than what OEM Mercedes delivers.

Thanks for this helpful and informative thread.
 

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Rather than creating another thread, I thought of posting here re: rebuilding Engine harness ...

The big black connector at the ecu and it's white pin-body can be separated after taking the small screw on top and then with a pointed tool picking away at the hardened epoxy sealant through where the wires go in. After the sealant is separated from the black plastic, push through the screw hole to separate. Once separated, you have access to each wire terminal and can be put back w/o cutting open any part of the connector.

I still would like to find answers to the first two questions in my previous post. Anyone who dealt with this?

Also, how do I know what size awg wires are used. Anyone know? There is one size which is the most common in the engine harness... what size is that? There are a few a bit larger. I don't need to go any larger than what MB has but want to be sure not to go smaller.

Thanks guys.
 

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After posting, I just noticed this thread title "Throttle Actuator Removal" and the thread is listed under DIY as "M104 wiring harness and ETA"

Is it possible for someone (mod?) to include Engine Harness and ETA in this thread title because this has info on both?

Thanks.
 

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Discussion Starter #39
Sorry for not posting sooner, I have been away.

If I recall correctly, the largest wire inte engine wiring harness is 12ga, and you will need an assortment of wire from 16 to 22 gauge. I bought 200 ft of each but found you really only need 50 ft of the 12 gauge. I used wire with ceosslinked insulation so I woulnt have and issues with melting later on. The ETA uses smaller wire 24,26, and 28 ga if I remember correctly. Use wire with a thin tough insulation so the the bundles will be smaller and allow easier routing.

I believe the connectors mblink is referring to along the left side of the engine are the injector connectors and they are available as replacements. I installed new ones.

The molded rubber section under the coil cover contains the primary side wiring and I simply cut it open so I could see how the wires were routed and built a replacement with the same configuration. I wrapped the replacement with self amalgamating tape so that it had roughly the same shape as the molded piece.

I hope this clears things up a bit.

Greg
 
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