NEWBIE!! 1989 300SEL A/C Blower only working sometimes - PeachParts Mercedes-Benz Forum

supercanuck · #1 04-28-2010, 06:55 PM

I just paid a bunch of money to have a new a/c installed in my 1989 300SEL so it would blow cold. It worked, but now the blower doesn't work. Strangely, the blower will work sometimes, but only when the temperature outside is relatively cool (unless it's purely coincidental, this seems to be the connection). Any thoughts on what might be causing this?

tinypanzer · #2 04-28-2010, 07:03 PM

There is a strip fuse located in a smallish fusebox which is separate from the main fusebox. It is located next to the first firewall a few inches from the main fusebox, is black, and has a little flip up top. There is a 30 amp strip fuse in there, and you will probably have to replace it every two years or so. My local MB dealer didn't have them, but my local VW dealer did, for $5. Or, you could do surgery on the thing and replace it with a regular style fuse holder and fuse and save some money in the long run.

macdrone · #3 04-29-2010, 04:50 PM

The regulator has gone bad, it has its own connected cooling fin and powers the blower. It is mounted under the blower motor.

tinypanzer · #4 04-30-2010, 10:47 PM

Quite possible, but I'd check the fuse first. It's a typical failure, even with the intermittency.

macdrone · #5 05-01-2010, 12:58 AM

once the fuse breaks no power will reach the blower, it will not be intermittent. It is a strip fuse on the driver side strut mount in a tootsie roll size box.

tinypanzer · #6 05-04-2010, 05:38 PM

Dude, not to get aggro on you, but those strip fuses fail intermittently all the time. I have had that fuse go 3 times, and twice it was intermittent. As I explained in the other thread where you bashed my advice, the fuse develops a hairline crack right in the middle, and for a while it will operate intermittently as thermal expansion/contraction makes the circuit open and close at that hairline crack.

Frankly I don't care if you believe me, I just hope the OP doesn't pull his regulator out before checking this simple and typical failure.

Sheesh.

dablk1 · #7 05-04-2010, 06:14 PM

Check the fuse before you do surgery. The blower motor itself might just need a little lubrication. It happened to me. It was intermittent, then it stopped working completely. Removed the motor, lubed it real good and I haven't had a problem since. Works like new.

hbofinger · #8 05-07-2010, 02:55 PM

... you might also consider replacing the brushes.

One the W126, the removal of the blower motor is not difficult, and brushes are available for pretty cheap on the web. All you need to know is how to solder...

shiny star · #9 05-09-2010, 08:22 AM

Mercedes-Benz 200E W124: january 2010, the blower works intermittently

Cause: fuse 30 Amps broken at the middle (not for overcurrent but for mechanical stress)

Changed with another new.

After five months the blower works ever fine!

engatwork · #10 05-23-2010, 12:24 PM

The crack is pretty evident upon closer examination.

shiny star · #11 05-29-2010, 09:29 AM

Conclusion: Intermittent fan equal broken fuse to 90 percent of cases (or more) (i think)

(the picture explains better than a thousand words)!

macdrone · #12 05-29-2010, 05:17 PM

Wull super whats the verdict?

urtruelove78 · #13 02-08-2012, 05:17 PM

For the records.

1. Check strip fuse first (30 amp outside fusebox) (should not be more then $2)
2. Check your ignition. Wiggle your key just a little.

Yes I know what I'm saying. Weird it may sound but my blower will quit sometime and i checked everything that make sense including strip fuse, bench tested blower motor and regulator was working fine too.
One day I was at my Indy and mentioned him this that my blower just cut itself from nowhere and it does sound like temperature based.
He said let me show you magic and he turned key in ignition just a little and blower started.

Since then i just have to wiggle my keys in ignition whenever blower stops intermittently and it never failed me.