No heater blower in any push button position on climate control!

After reading mostly all of the posts here from a search of similar 'heater woes' after my blower quit, I checked #5 fuse and the 30A strip fuse and were good. I also applied 12v to the blower fan which spun OK, however no voltage coming out of the hot lead going to the blower. Next I removed the climate control unit and took off the back cover to expose the circuit board like a few guys had done on this forum. I had not cheked the monovalve or the aux-heater pump yet.

The circuit board looked perfect, but I was prepared to send it out for rebuild anyway. I then got my trusty soldering iron out and said to myself, 'what the heck' and tried what some of you guys had done and reheat the joints.

There are like a thousand joints on this board and I was not going to heat all of them, so I heated up the six joints per push button mount. Also I heated and added solder to the two 12-point power plug joints on the board where the cables plug into the unit and put it back together and threw it back in the car for a test.

"Violla" it now works like a champ! Reassembled the rest of the odds and ends.

My hats off to you fella's for giving me the inspiration to track down this glitch.

No more cold feet! Thanks guys.

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Gerry

59 Ranchero
83 928 Euro S
84 928 Euro S
87 300D Turbo-Frybrid "WVO, Tastes Great - Less Filling"
90 750 IL
91 560 SEL

A combination of wave soldering and vibration causes the solder joint to crack causing open circuits. Adding more solder cures this problem.

Oh, and congratualtions on taking the plunge.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

A question: why is it often called "heater blower" when it is the same device that blows the air for the air conditioning system?

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1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

Thanks Warren. What do you mean by 'wave soldering'?

Braverichard - The term 'heater blower' goes way back to pre-airconditioning days, like in the 1950's and just stuck I guess.

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Gerry

59 Ranchero
83 928 Euro S
84 928 Euro S
87 300D Turbo-Frybrid "WVO, Tastes Great - Less Filling"
90 750 IL
91 560 SEL

HA! That makes sense. Thanks!

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

Congratulations on fixing your fan. I, also from threads on this forum, did almost the exact things last week on my 300SD and low and behold I now have heat and fan too!!!

Now if someone can come up with a plan to get my tranny to shift up to 3rd (without having to remove it) I will be eternally grateful. Have tried most of the vacuum checks, replaced the 3/2 valves and now have only the Bowden cable to check when I get her on a hoist. Previous owner fractured a line and ran her dry. Any and all suggestions appreaciated.

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The meek shall inherit the earth, the brave shall get the oceans

Thanks Dick. You see, it does pay to be persistant towards a common goal! Glad you fixed your heater too.

As far as your tranny, sounds like a rebuild job to me. I had a tranny go Kaputt in my BMW 750il and I found a good used one on ebay for only $500 plus $250 shipping from good salvage yard in New Mexico. I installed it all by myself and now she runs great. (ahh, the lift in my heated garage helped a little too)

If no lift, try your local shop and see how much he would charge for just installation, if you can locate a used tranny (about $500).

I bought a remanufactured tranny from my local Mercedes dealer for my 560sel about 5 years ago, when it started slipping and it was only $1610.

You have a great website and a beautiful boat. What a great adventure! Are you down on the boat now? I had a 37 ft Egg Harbor, all wood, twin 454's sport fisher. Sold it though, I sure miss it.

__________________
Gerry

59 Ranchero
83 928 Euro S
84 928 Euro S
87 300D Turbo-Frybrid "WVO, Tastes Great - Less Filling"
90 750 IL
91 560 SEL

Congratulations on fixing the problem.
This is another success story owed to the good guys that contribute in this forum, as well as the sponsor of this forum (MercedesShop)

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

After doing my diligence and searching the archives I found the reason for my fan blower motor's demise (1989 300SE W126).

It was the 30 amp strip fuse.

Thanks to Sixto and all the others who posted location of fuse, location of blower motor and access steps.

And WHunter for posting links to the subject (found later).

fuse cost $3.45 at the dealer.
Costs alot less at FASTLANE.

Thanks to all members of this site !

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

"Thanks Warren. What do you mean by 'wave soldering'?"

Wave soldering refers to a process used in mass production of circuit boards. It's a simple idea, and frankly surprising that it works at all.

A circuit board, stuffed with all its components is suspended component side up over a pool of molten solder. The distance is very small. Then, a mechanical device produces a wave in the molten solder pool. The crest of the wave travels the length of the pool and back, and as it does, it solders every joint on the circuit board at once.

Pretty neat stuff, but you can see that since all the joints are done at once, the possibility of a poor connection on one or more of the joints is quite real.


-tp

is a common failure on the w123's all the same? i have a 280e and my climate control dont work . only the defrost works ,could this be a unit or motor issue?