What the hell....my 1990TE was working and running perfectly...all the sudden...no A/C, no vent, no nothing....zippo....no air movement at all. It is like the entire ventilation system has shut down. The A/C compressor is NOT engaging...the fan is NOT turning....no air, fresh or otherwise, coming through. I have never driven inside an oven before...now i know what it is like. Temps here have been 100 all week...and it will continue like this till October.

No matter what button....nothing...just dead. Turn the temp dial....nothing....just dead.

Is there a particular fusible link or fuse that could cause the entire thing to go down?

If one thing happens like the A/C compressor fusible link burning out...would that cause the fan to stop working in vent mode?

PLEASE PLEASE SUGGESTIONS? ALL FUSES SEEM FINE, BUT I WILL MULTIMETER JUST IN CASE

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1990 300TE....all comments are about this car...in case I forget in the actual post

I just read this great post over at diesel 100% Climate Control Failure: Vacuum, Electrical, or Both?

This guy said his ACC caused this same problem. I will give his fix a shot

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1990 300TE....all comments are about this car...in case I forget in the actual post

Funny stuff....I am finding once again...that as I ask questions...in my persuit to give you guys more info...I stumble upon the solution. This time is no exception....I blew that inline fuse(F15), which is the blower motor fuse. Did not even know it was there...and in the daytime, I completely missed it. I went out at 2am with a flashlight to check for something else...and there was the inline fuse, right in front of the fuse box, partially melted. You can see the strip inside is broken.

Now the hard questions.....

What caused this?
Is this particular fuse known to blow even when there is no short in the system?
Can I replace it with a breaker type of fuse?

And anything else you might add

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1990 300TE....all comments are about this car...in case I forget in the actual post

Saint, replace the 30 amp strip fuse and you should be good to go. I had a similar situation to yours with our 1991 300CE a month ago, but the fuse wasn't melted, just cracked in half. I replaced the strip fuse and everything was back to normal. You can buy the strip fuse online for less than a dollar. Do a search under "Body Electrical" at one of the websites.

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Fred Hoelzle

Yes, this site has been frequented and responded to by some of the best MB techs anywhere for over five years. For that reason there is LOTS of good information available by simply doing a search.

Good luck,

Ferdman....my manual shows this to be a 30amp fuse. The strip is broken, but the outer black plastic enclosure melted right in the middle so you can look inside and see the strip is broken. The strip has a 30 stamped on it. This cable is THICK. It has to be about 8 gage wire, or maybe 10....all this leads me to believe that it is in fact a 30 amp. Where did you get 15 amp from...and do you think I have this wrong?

UPDATE...Because it was late when I checked it last night...I did not give it GOOD going over. I just went out there and popped the melted lid, removed the broken strip...and am looking at it now. Yep, says 30a on it...right where it broke. Problem solved there....now where to buy these where I am not paying more for shipping than for the item itself...lol.

Larry....I ALWAYS search first...but as we have all found out...searching is a whole lot of miss. Just about every problem and answers have been posted at one time or another, but sometimes(most of the time )...it is like a needle in a haystack trying to ferret it out of there. I have so many threads bookmarked right now...lol....I could write a book. And...most of my bookmarked threads have come from searching for something else, and some unrelated thread will pop up having my keyword in it...and the thread being pretty darn interesting for another time.

I love this site. The best MB forum, and really the only one I frequent anymore. Wish I could be more of a contributor...but I am still a MB newbie bout 2 years now.

Thanks guys

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1990 300TE....all comments are about this car...in case I forget in the actual post

Don't be afraid... try a Dealership, especially if one is close or on the way... Most maintenance parts parts like fuses, light bulbs, antifreeze, wiper blades, are usually price competitive. Check them out.

Best Regards,
Jim

Saint, it is a 30 amp strip fuse. I corrected my mistake on the previous post to clarify things. The melted black plastic case may be due to arcing of the broken strip fuse. As for shipping cost exceeding the value of the strip fuse, order some other items so that you exceed $50 for free shipping. Surely you'll need an air filter, oil filter or brake pads soon.

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Fred Hoelzle

The dealership is too far...but still a good suggestion. I have two of these cars, so I am yanking this fuse from the other one since it is currently undrivable.

Gosh...I dont know if I could meet that 50 dollar minimum for MB stuff.

HEHE...LOL....

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1990 300TE....all comments are about this car...in case I forget in the actual post

glad you found the problem. i am always happier w/ a total failure than a partial one as the total failure usually is something simple.

HELP!!!!!

I replaced the fuse, and the fan came right back on. Yeah, I think to myself. I hit the A/C button...I see the enono gauge slide over to about half way...then right back to zero. OH NO...NOW WHAT!!???

The A/C compressor is turning on for a very short (1 second) time, then shuts itself off.

I hook up my A/C gauges, and the low side about goes off the scale....and it is the same as the high side. Now I am thinking...what..the expansion valve or something? I know that the A/C compressor will kick off above 60psi on the low side to protect itself. So, in my wisdom and frustration...I start venting out some pressure. This is enviro safe, not freon. I get the pressure down to 50 on both sides...and still no joy. I drop the pressure down to 30....and still no joy. I have to turn the engine off...then turn it back on...then hit a/c, then the a/c turns on for about 1 sec, and the econo gauge reads higher than normal for a/c use, then the a/c shuts down.

Now, even if the expansion valve is bad, and causing the high and low sides to meet...shouldnt the drop in pressure below 60 get the compressor going again? It is not. I left about 20psi in the system.,....and the compressor still kicks off after about 1 sec on first use after starting the engine.

AAAHHHHHHHHHHHH....it is so hot here is so Cal...and expected 103 all week

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1990 300TE....all comments are about this car...in case I forget in the actual post

First, you should not have vented your refrigerant. It is normal for the high side and low side to be equal when the compressor is not running. There is also no cut-off for the low side being too high. There can't be, or the system would never start up.

Second, your symptoms sound very much like the system is shutting itself off because it's detected a speed variation between the compressor and the engine. At compressor start, the system compares the compressor speed to the engine speed. When the compressor speed is too low, it is interpreted as a soon-to-seize compressor, and disengages to save the drive belt...thus allowing you to continue driving instead of being stuck with a broken belt. This could be due to a faulty compressor speed sensor, a faulty ACC controller, or your compressor could, in fact, be ready to seize.

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1989 300 SEL that mostly works, but needs TLC

yeah...i knew I should not have let out most of the pressure...but damn ..I was ticked when the fuse did not cure my problem....I can be such an idiot sometimes.

here is the thing about speed....It "seems" like the compressor is dragging hard...that is why I made the false assumption that maybe the high side was slipping pressure over to the low side....what do I know???

Back to my point...when the compressor first egages...does it take your econo gauge to about half way before settling back to about 1/4? I dont rermember mine doing that. I remember it going from zero to 1/4, and thats it. Now, when it engages...it goes right to the half way point..then shuts down.

I was considering manually engaging the clutch...but it may make things worse...i dont know...

I have heard of the ACC controller thingy causes problems...do you know where this item is on a 1990 300TE?

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1990 300TE....all comments are about this car...in case I forget in the actual post

The Economy gauge shows manifold vacuum. High vacuum = light engine load. Low vacuum = heavy engine load. It sounds like your compressor is putting a bigger load on the engine than it used to. Sorry to say, but it is looking like the compressor has opted for early retirement.

I'd suggest that (with the engine off, of course) you try turning the compressor by hand. If all is normal, you should be able to feel some resistance, but should be able to turn smoothly. If it feels rough, or you are unable to turn it, then you're probably looking at a new compressor. If you're not sure how it feels, then find a vehicle with working A/C, turn that compressor by hand, and compare to yours.

If, however, it turns smoothly without excessive effort, then we start looking for other causes.

Good Luck

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1989 300 SEL that mostly works, but needs TLC

Turn the clutch by hand?

The compressor has two "rings". One that the belt is actually spinning(inner), and the one closest to radiator (outer)which would also be the clutch. The outer ring gets engaged to the inner when activated. Does that all sound right?

Now, turn the clutch by hand? Is this with the belt on or off? It is a very tight fit in there...do I come up from underneath the car? Dont think my hand would fit in there. Do you use channel locks or something? Sorry for my ignorance....have not spent too much time working on these cars, or A/C for that matter.

Thanks so much

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1990 300TE....all comments are about this car...in case I forget in the actual post