1994 Mercedes E320 Engine Wiring Harness Replacement (W124 chassis, M104 engine)

[@Dezhighspeed]

Man you do not no how much you really helped me, I have a 1994 E420 with a very similar layout and it will not start, and the harness is degrading, but I'm ordering one as of thursday I miss my car.

[@majorsnodgrassthethird5699]

I have a 1994 E320 Coupe and luckily the wiring loom has been replaced. If you go for an E320 Coupe now in 2015 make sure the loom has been replaced unless you can do what this guy did in the video. Also check head gasket has been done too. They are great cars but under appreciated so only buy if you have plenty of spare money to fix them as they can be very expensive to fix at times. BUT you wont regret buying one and driving it around even if you don't get your money back..

[@sambking]

eallevato, Thank you so much for posting this video! I am about to embark on the replacement journey myself. The search begins for an inexpensive harness that can take the heat. Thanks again! Sam

[@eallevato]

In the past couple of years, I had the Check Engine light come on a few times. The mechanic troubleshot the components associated with the DTCs and could not find anything wrong. He suggested replacement of the harness. After reading the forums, many folks reported if the harness is giving problems to replace it, as it may fry the ECU. Glad that I did, as my harness had many wires with the insulation completely gone, and connectors that disintegrated when I grabbed them.

[@scherrit]

Thanks so much for this detailed guide! really appreciate it.

[@tonyvargas368]

I’m not mechanically inclined at all. I find this type of video fascinating. When it came time to replace the wiring harness on my 1995 E320, I literally just took the car to my mechanic and gladly paid him to do it.

[@billnadeau7136]

I was successful yesterday in replacing the harness on my 95 E320 Coupe, but it was a saga. My harness was the ____2933. I believe yours was most likely the ____5632. Big difference! There are several connections that required my wife to help with her slimmer arms to squeeze into blind spots. I only weigh 135# so my arms are not that large either. One connection required me to jack the car up to get at it from underneath the driver side. This must be the reason the 33 harness has a higher price than the 32. i.e. More connections. After 4 hours, I successfully restarted the car

[@eallevato]

Congratulations!!! Yes, my harness was ___5632. Perhaps, you could make a short video to follow up my video, explaining the differences. It sounds like your effort was a bit more challenging than mine. Congrats again.

[@mercedestopseals5792]

They made less than 1/2 number of the 2933 vs 5632. I have used upgraded engine wiring harnesses for e320's, both # 2933 and 5632 and for many other Mercedes models s500/s420 s320 e420 e500 sl320 sl500 c220 c280, s600. The throttle body (eta) uses the same crappy wiring, I have used upgraded eta for c220 c280 e320 s320 SL320 S500 S420 SL500, s/sl600.

[@dredastardly6771]

When reconnecting all the plugs shown at 15:41, which wire goes to what side? Each plug end has two wires, one white and one red/brown I believe. The new wiring harness I have has the plug ends broken off and the wire ends are exposed. I connected everything else correctly and started the car up and it stutters and goes into a limp mode and then cuts off. The 2nd time I started it up, it stayed on but ran horribly so I cut it off immediately. I believe I may have gotten the wires backwards at some end.

[@manekdubash5022]

Thanks so much, very clear. This is my next job...

[@TeamHURSTOLDSRich]

Ive watched a few of your videos very informative. Good job.

[@eallevato]

There is supposed to be a white tag around the harness with the manufacturing date info. It should be located near the inside side of the battery. On my original harness it was missing!!! The newer harnesses have them. Good luck

[@scotttaylor8811]

I just tried this by myself. Not quite finished, but almost. I appreciate the video thank you. Even though it describes a bulk of the work I found it mostly goes through the easy to reach connectors. I have 4 connectors still not connected. One of which was in the video, but you just said that one down there is a bitch. I would have love some strategies on getting those. Those are two of the hard to reach ones. I am using the 2933 harness that I got from Ebay for $250 shipped. It is a 2006 Delphi. There is another connector at the back/front of the engine near the firewall. The last unconnected one is a short one right in the middle of the harness tray. It was not connected on the car I took it off from and I have not figured out where it goes yet and it is not obvious. Took me many hours so far, but I have been cleaning along the way. Can't wait until I can fire it up. Update: One of the unidentified clips was for the Air Charge Temperature Sensor that plugs into the crossover tube. Three left the two that connect to the side of engine block and the one hard to reach one between the engine and the firewall.

[@wadayoub]

Please explain to us the connection of the tubes of the vacuum device .Because I bought a car and found this device in the trunk of the car and did not know how to connect it

[@jagveshjagernauth8049]

Hey guy …. I have a leak in the front of the engine …air filter housing side ….above the alternator. Any thoughts?

[@redpig1120]

Great video..was it running bad

[@indotube8125]

Is the new harness for w124 still produced ?? Is the bew one still biodegradable ???

[@geoffroberts1126]

I have a Ssangyong Musso that uses this same engine, made in 1996. They use a power train built in toto by Mercedes. Seems to not have the overall deterioration issue, however, I had a long standing fault with the cam sensor, replacing it (twice) to no avail, then swapping in a s/h ECU which didn't fix it either. I decided it was the cable (being the only thing left) and cut the connector off the end in preparation for replacing the cable. The cable from the cam sensor on these (it's a passive reluctor on this model, not the later Hall Effect device) is a type of coaxial, shielded cable. When I cut it, and sliced it open, I discovered the internal insulation between the centre conductor and the shield had vanished into a bit of greenish mush and the cable was shorted internally, so for some reason that cable does seem to have this issue. This engine had a timing chain let go (before I owned it!) and the cam sensor was smashed in the process of it letting go. Head was rebuilt, but the cam sensor was faulty according to the computer from then on, despite being replaced (twice). I have a friend with the same model Musso and his cam sensor works fine, so I suspect that it's probably ok until it's significantly disturbed - bent and pushed around a bit - as it was when the head was removed and cam sensor replaced etc. I'm going to replace it with some RG58 50 Ohm coax which should finally fix the issue - the rest of the wiring harness, including the wiring inside and around the throttle body is fine, no sign of deterioration at all.

[@SY-ml5nl]

So you can swap the ssangtong 3.2 wire loom with the mercedes 320?

[@rahsiadiri5510]

Very useful video bro. Thanks a lot...

[@karasu5000]

Great videos!!! I'm working on my 1994 Mercedes Benz E320 as well, so these videos are proving to be very helpful. :-) Also, do you know what would be broken if my heater and defroster aren't working? I've replaced the blower motor, relay, and the climate control unit and my heat still isn't coming on. Is it possible that it's the blower motor regulator or blower resistor? If you have any ideas that would be great. Thanks!

[@classiccarssp]

Thanks for your video 👍

[@jamesreckling6697]

Have you replaced the other wiring harness?

[@jonthenn656]

Would this be the same steps if I were to replace my 1995 c280?

[@nabildawahre4915]

Hi, Please let me know where did you get this used parts :1994 Mercedes E320 Engine Wiring Harness Replacement (W124 chassis, M104 engine)

[@Level_Up_Nation]

I have a 95 SL 320 and after paying 3200 to get it repaired once already just to have it fail again in 2003, have left the car to sit in my garage..since 03 lol is there a aftermarket harness out now? the shop put another Factory one on..hence the recurring issue..would love to drive it again.

[@arvidsamuelsson]

Thanks for the very good video that really helped me a lot doing the job myself. I got the original ....5632 wire harness for my 1994 E320 coupe. The engine starts and runs ok but still has the varying idleing when in Park. So still there must be a problem? And btw I have one contact left over that does not fit anywhere. It is up front near the thermostate. It is oval with 8 contactholes (numbered 1 to 8) and has a red gasket ring around it. Where should this fit? (No cruisecontrol on my car.)

[@Disruptedgarage]

Thank you for this!

[@tonyc926]

Hi Eallevato, this has been enormously helpful for us as it took us a long time to diagnose this problem and Mercedes Benz of Beverly Hills acted like it was our fault and wants to charge us in excess of $3,000 to fix. Are you aware of any class action lawsuits regarding this obvious factory defect? Thanks again and Merry Christmas.

[@eallevato]

I don't know if there is a class action, but it sure seems like there should be one.

[@torquemonster290]

eallevato I agree with this- 1 year later, and I have the same problem.

[@tommervaag92]

Did you try to change the oil pressure guage (the sender unit mounted on the oil filter housing)? I had the same problem on the same car, and the problem on my car was a defect sender unit.

[@mercedestopseals5792]

Yes, I still sell a lot of used updated harnesses for 1993 300e's and 1994 e320's also 1995 e320's and have most 1992-1996 harnesses available including diesel and v12 600's

[@SpenserRoger]

Mercedes Top Seals Link?

[@eallevato]

I am just catching up to the questions, so I apologise for the delay. I would think that there is an electrical test to check out the sending unit. I mean using a voltmeter to measure the output voltage out of the sensor(s). It looks like it might be a connection issue on the back of the instrument cluster or the gauge itself might have gone bad. Good luck.

[@autojock4472]

hello i like the detail that you used in video attention to detail super job, i have question if you can help, my 94 e320 stop registering oil pressure on the gauge inside took valve cap off while running oil shooting everywhere but no oil pressure on gauge replaced sender from oil engine that was working no pressure still what do you think.

[@heartsongful]

Thanks for the extremely helpful walkthrough. Could you explain how to release the straps that hold the cables down? I am having trouble getting the cover off on the drivers side for access to one of those last connectors. Is there an easy way to remove it?

[@eallevato]

Yes, that one was a bear to remove. As I remember, I just used a flat blade screwdriver and pried the tabs until it popped off. I think there are 3 tabs.

[@philipcooper8297]

Do we know what engines had this biodegradable wiring harness? I've got a '95 w202 C200 CGI, M111 engine and I can't tell. The car runs alright, but safety first.

[@middletonomalley3258]

Nice job and very informative!

[@Mediagiant28]

So I am looking to buy a 1994 E320. Is there trick to determining if the wire harness is defective? Other than visually looking? Is there an ideal part of the harness to inspect?

[@eallevato]

+Rich Rossway There should be a white tag on the harness near or around the battery area, and it should list the manufacture date. On my car it was missing, however one could see bare wires in the harness near the thermostat area.

[@johnd6782]

Thanks to your video, I was able to complete 99% of the WH swap. There is a ground wire and connector that attach behind a small black plastic box on the driver's side wheel well. Do you know what size nut holds the ground wire? It is too tight to be loosened with a small wrench. I tried my 5mm socket and it was too small. It think it has to be between 5.5-9mm. Any help you could provide would be greatly appreciated.

[@Level_Up_Nation]

all that needs to do is be attached to the frame (ground) if thats all it's running too, if that helps.

[@agron1974]

Is there a way to tell if the wire harness is replaced? Is there a code or date on the wire? Thanks

[@richardnorris553]

Thanks for the video. Based upon the confidence of it, I attempted to do mine (95 E320 Coupe) and found it exactly as you explained. However, you left out the procedure for a few of the more difficult connectors. The connector that leads down by the oil filter housing cannot even be seen from under the car and the two on the block under the intake manifold are seemingly impossible to access. Any advice would be greatly appreciated. Thanks for all your great videos. Your car looks beautiful. Regards

[@eallevato]

Yes, some of the connectors are tough to get to, but they disengage fairly easily. Some of them you have to do it by feel only.

[@baytcelu3379]

God bless you man!

[@billnadeau7136]

Thanks so much for the great video resource!! 2 questions: 1. For the lower clamp that holds down the air crossover piece for which you advise using the long handled screw driver, is there a screw holding the clamp together or just a tab. It is very hard to see under the manifold. 2. I read a post a few days ago, but can't find it again whereby someone said that one should spray WD-40 into one of the fasteners and let sit overnight, because it is difficult to break free. Did you have a similar issue, and if so, which one(s)? Thanks so much again! Bill

[@eallevato]

The lower clamp is a worm drive type hose clamp around 3-4 inches in diameter, and yes with a long screwdriver and by feel you should be able to loosen it and remove the crossover assembly. I did not have any issues removing any fasteners and did not have to use any spray lubricants. Good luck.

[@jellevr1983]

Great video👌🏻

[@ShirleyAerial]

What symptoms were you having with your car that made you think of replacing the harness?

[@علاءفاهم-خ9ق]

Thank you sir❤

[@TheWolf326]

Very usefull Stuff!

[@MrOliveira1111]

Thank you 🙏🏼

[@umarche81]

Many thanks you,for video.Hope will else

[@eallevato]

I suspect that it would be nearly identical. Just start at the big connector and do one connection at a time.

[@pavelb2649]

Hi.I bought the same harness. But on my old harness is one more another plug socket He goes to the throttle body. Can you help me, please ?

[@eallevato]

As I mentioned in the video, the 1994 model year has 2 different part numbers for the engine harness. You have to look up your chassis number and order the correct one.

[@eallevato]

Thanks. The climate control system is a bit complicated. I found a very good website that list a pretty complete set of maintenance manuals and circuits. It is called w124-zone. It sounds like you have replaced most of the usual suspects. You should be able to test the blower resistor with an ohmmeter. It could very well be the motor regulator.

[@clamberthjr]

my car is stuck in limp mode with the junk wire... will just the wiring harness fix that?

[@eallevato]

Typically, limp mode is engaged to protect the transmission, but maybe a badly degraded harness could cause the issue as well.

[@johnyon123]

eallevato Hi.. In the morning, even after a warm up, the transmission does not shift from 1 to 2nd gear until I drive for 2-3 minutes (still at gear #1). I heard that this is normal for 1996 e320 (transmission 722.6). Someone told me that this is to protect the tranny? Is this also called "limp mode"? What can be done so that the car will shift into second gear when I drive off? Thank you !

[@esanding]

John Yon You can reset the transmission with the use of star scan tools and works fine again.

[@johnhayward7730]

thank you , very much

[@lisadangeltorres]

can you give me instructions on how to disable alarm system in e320 cabriolet 1995?

[@Omardottcom]

Great Video

[@lma112567007]

Can anyone post where I can get a rebuilder kit or a new non biodegradable harness at a fare price. Thank U 😢

[@jkausg]

Changed today ;-)

[@kristianbardhi4821]

Hi can someone help me to find a page or internet adress where to order those (Wiring Harness) ? im looking for them but is not so easy to find . one adrees would help me, Thank you !

[@tsimons2889]

1994 e320 # 5632 harness >>> round thermostat plug 1994 e320 # 2933 harness >>> square thermostat plug Do not use your VIN to find the correct harness for your car, last May the MB dealer (or online parts supplier) was wrong twice. I have used updated engine wiring harnesses for most models available at www.mercedesenginewiringharness.com

[@Adoradorsoy]

Nesecito saber en dónde puedo ordenar este ser de cables ? Me urge please I need to bay this wiring harness replacement

[@eallevato]

Puedes comprar en Ebay.

[@queenofheart2heartstalk]

I NEED TO PURCHASE A WIRE HARNESS FOR A 1996 MERCEDES BENZ C220.

[@cutemanzwa]

where can i find Mercedes Benz A 2025403832 Engine Wiring Harness diagram?

[@eallevato]

Try the website w124-zone. They have a lot of documentation.

[@cutemanzwa]

i need it to wire o2 sensor to ECU without o2 conector >>>help me plz ??

[@eallevato]

I don't know about that one, have you tried some salvage yards to find the connector?

[@palewriter1856]

Wow - biodegradable insulation on wires that lay right upside the hot engine - in a high-brow piece of german engineering like ours? A couple years ago when I had to have mine replaced (even same color as yours) I was enfuriated by the obvious QC shortcoming that would allow insulation to just crack up and fall off and short things out - but I had to pay the piper anyway. It was the last straw in a horror story that started out as a few C-notes to fix an oil leak, which turned into 4500 before I could get it back. Worse yet, ever since, I've had even more electrical issues than before I took it to this wrechanic. Now the cruise control won't EVEN work, nor the outside temp, and worst of all the engine temp wigs out most all the time and the needle jumps to max - indicating it's WAY overheated even though it's running at normal op temp. Well, had I known how easy this task was, I'd have done it my own self, but I would have had to get it TOWED from that shop to my house - so I let him do it. Of course the thing isn't worth near what that cost, so I'm gonna have to drive it until I can no longer buy gasoline to get my money's worth. So I've been perusing dubyuh124zone as you mentioned, looking for schematics and info to troubleshoot these issues - so far no luck - but thanks for that tip anyway (among others). I always appreciate seeing good, common-sense technicians at work, especially when they can create and share well-done videos. Carry on! p.w.

[@ManiaRockinRecipes]

i have a 1993 300e .. does this matter?

[@earlallen8684]

Yes, unless it was already renewed. The Electronic Throttle Assembly (ETA) has the bad wiring as well. But if it is not disturbed it may not present symptoms. Look behind the battery for the label on the base of the wiring harness to see if the date of mfgr is still readable.

[@ManiaRockinRecipes]

thank you

[@dadangsubandi67]

Mercedes - Benz alus euy

[@yogavnture1]

I have a 94 e320 sedan In excellent condition with 70000 miles on it. that's right 70k its been sitting in garage. I don't know what to do with it. I'm tempted just to wait someyears and maybe someday it will be desirable as a restoration car? anybody got an opinion on that? also. should I do anything as the car just sits. i did remove battery. but I know it has at least a gallon of gas in the tank. with stabilizer , but the fuel is now 3 yrs old. I'm tempted just to take gas cap off and wait a few months. will it evaporate out? any opinions on what I should do as the car sits for years without use? maybe i should get old gas out. and jjust but bits of fuel in engine and let it run for a a bit each year?

[@simeonsimeonov4776]

It good to ride or start the car from time to time and is good to have fuel in the tank for fuel pump

[@yogavnture1]

simeon simeonov does this car have any value to me. hate to give it away 70k original miles and runs good. just sits for at least 6 years now

[@simeonsimeonov4776]

Keep it some young fella from ur family one day maybe interested, better if u have son to work together on the car :)

[@mercedestopseals5792]

I have used upgraded engine wiring harnesses for e320's, both # 2933 and 5632 and for many other Mercedes models s500/s420 s320 e420 e500 sl320 sl500 c220 c280. The throttle body (eta) uses the same crappy wiring, I have used upgraded eta for c220 c280 e320 s320 SL320 S500 S420 SL500. And: rebuilt top cylinders and cylinder seal kits for Mercedes r129's SL320 SL500 SL600 300SL 500SL 1990-2002. All are available at mercedestopseals.com

[@esanding]

I just change one got it from ebay around $ 189

[@XMercedesXBenz]

Hi guys me too i change my engine cables harness 1400€ foukk... ( mercedes w202 C220 petrol pack amg 1994 217.000km ) i have now another problem my garage told me to change body throttle (1200€ garage , ebay 400€ , foukkk.... :(

[@Hippiekinkster]

So a new harness costs a gazillion dollars Euros Yen Pounds Renminbi Dirhams Zlotnys NYC Subway Tokens Lortabs 5.56mm bullets BJs whatever why"