Hopped in the Benz ( 1990 420SEL) yesterday to head for work and when I went to turn on the A/C, the fan wouldn't blow at all no matter which switch I selected. I could tell the air was working but without any fan blowing I was basically SOL and hot.

I'm hoping that it may be a fuse or something? I'm not real mechanically inclined so that's why I'm turning to you pros in here.

Thanks in advance for any tips or advice.

Cheers, Todd

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1990 420 SEL / 151K mi.

Hi Todd,

fuse number 5 (8 amp) supports the climate control system and other things. The fusebox is in the engine bay driverside between brake fluid reservoir and the levers that hold the hood up. Inside the lid is normally a card that describes the circuits. If your's is missing, the dealer sells them for about a $.

Good luck

Reinhard

as a quick & dirty fix on my 560sel, i give the panel under the passenger side dash an open-hand slap to fix the intermittant quitting of the blower motor... works fine for a few hours up to as much as a month.

I had the same thing happen to me. I had to replace the blower motor regulator. Mine just quit, replaced that piece and has worked just the way its suppose to ever since.

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90 300TE
00 ML320

...above-referenced "blower motor regulator", please?

My '91 420SEL has just developed the identical problem: I can hear the various valves working going from A/C to Econ, but no fan action on high, low or auto positions...

Fuse #5 (8A) is fine. Could it just be the switch itself?

Thanks in advance for all consideration!

Cheers!

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'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435

there is a 30 amp "strip fuse" located in front of the fusebox also that solely is for blower motor. could also be your regulator....

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Mercedes-Benz master certified tech

That's what it was... Sorry I didn't post back sooner

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1990 420 SEL / 151K mi.

post back sooner?? ha, i just posted that one about an hour ago

Mnstang is a former coworker of mine. He's a sharp guy and we're lucky to have him answering some questions.
Welcome him!

Gilly

REGULATOR is located where...? I'm not familiar with the term "strip fuse", either. Duh, me!

Thanks!

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'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435

i don't know how to explain what the fuse is, it's basically held in with 2 screws, one on each end. it's basically a really really thin piece of metal. (i think aluminum?)
it is in front of the fusebox, it has it's own little holder for it, it's plastic and you have to flip a lid open to see it.
the blower motor regulator is right by the blower motor, just follow the wires from the motor and you'll get right to it!

edit, thanks for the welcome there gilly.

Right, you'll see it behind that "front" firewall, it's in this little plastic box, looks like a small plastic coffin or something. Over in front of the fuse box and brake master cylinder, in that area.
If you're familiar with MB Diesels, it's the same type of fuse MB uses in the glow plug relays.

The blower motor itself is on the bottom side of the dash on the passengers side, you need to drop that under dash panel down to get to the blower motor, and that regulator is in that same area. Not a bad thing to work on compared to the 124 and 201's.

Gilly

I'll be digging in there tomorrow, under dash on passenger side for blower motor & regulator, in front of fuse box for "strip fuse".

Are there any exploded diagrams available on the Web for W126 OR W116 Series cars? I know there are sites with this kind of info for other makes (i.e. my SVX) but have not needed this kind of info (yet!) for my MB's.

Regards!

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'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435

In the litle black plastic "box" in front of the fuse box & towards the centerline of the car...

Be sure when checking this fuse to use a meter because mine looked to be 100% OK, but there was a hairline crack in it.

BTW- Blower motor was drawing 15-16 amps which my tech said was just fine.

I'm a happy camper, now!

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'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435

Mine 89' 420SEL has same problem.

Heat and ac were working but stops in between and restarts again. I didn't bother until it stopped completely and i have to drive it to work instead of my 93' 300E.

When pressing high/normal/low buttons, Can hear small hiss from vents and engine was responding with little vibration but no fan was engaging.

Never did anything myself except changing one rear bulb on MB's.

Was worried that will pay $200 or more at dealer. Tried to search for problem here for week or so. Once got familiar with terms and parts was easier to look around on these forums now.

Mine 30 Amp strip fuse looked intact like new. Touched it and there it is 2 pieces.
Went to Mercedes parts store, bought one for $2 replaced and fan started again. voila...........

Never been happier.
Thanks for all member contributions.
Please update the forum once your problem is solved and what it was...It helps great deal