I read in a thread here that the master blower switch is located behind the glove box in a W123. I can't see it. I have searched the shop manual but can find no mention of where it is located. It shows pictures of it.The pictures show what it looks like, but offer no clues as to where it is located.

Anyone know?

Richard

Do you have automatic or manual climate control?

If automatic, horizontal or vertical pushbuttons?

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

It's a 1980 300D with the old style vertical buttons and the evil servo.

Richard

Link to manual, it is for a Chrysler but MB used this system too.

1971 Chrysler Imperial Auto-Temp 2 Service Reference Guide - Session 281

Blower control is by the servo and a stepped resistor under the hood.

There is an analog amplifier that drives the servo motor under the dash.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

The master switch your referring to I believe is behind the center console, possibly in behind the ash tray if memory serves.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

On

The relay for the blower motor is behind the glove compartment. It's on a bracket bolted to the firewall.

It looks like the generic relays but has more pins.

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

The master switch he's after is the vacuum operated one isn't it? I'll have to check, but I'm pretty sure its not behind the glove box.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

refer to post #58
need help!! no heat!! brrrrrrrrr.... - Page 6 - Mercedes-Benz Forum

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

I agree.

However, when someone asks about something and gives a specific location, I tend to wonder if they meant the part located at the spot in question and possibly they used the wrong term.

I have been right before... maybe not this time.

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Yes, that's the one I'm after. I see that in some Benz schematics it's called the "master blower switch" and in others it's called the "main switch". Go figure.

The link that Dude99 posted shows it to be located behind the center console.

I have decided to continue using the defrost button and stop making myself miserable. The blower and compressor run fine on Defrost. I live in the tropics and will never have to use a car heater or a defroster again. All I had to do was wire the valve on the firewall closed: the valve that allows the passage of coolant into the defroster core when the vacuum system is down.

Richard