Hi All--

Car has been in the shop for a bit. I replaced the heat sink compound for the blower motor resistor as it was dried out and non-existent.

Now, I can't get the blower motor fan to operator in any fan speed.

CCU fuse 7 is good. The heat control changes the temp of vent air and placing the CCU in defrost causes the A/C compressor to engage.

I haven't checked any strip fuses or wiring but no clue what would have changed.

Any clues?

__________________
Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

The blower is fed from either fuse 12 or an external fuse on the shock tower.

There was an engineering change to remove the 25 A fuse 12 and use the external 30 A strip fuse pretty early in 1987 MY. So if you have an early 1987 with fuse 12 you want to find the strip fuse holder and install it. It just goes across the screws for fuse 12 in the back of the fuse box, and of course don’t install a cartridge fuse in 12.

Wait just saw your sig, you have a 95, you will have the strip fuse. Check for micro cracks, they can look good and even ohm good cold but open up under load.

The ‘resistor’ in a 124 is actually a switching transistor controller that pulse width modulates the voltage to the motor to regulate the speed.

__________________
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

Thanks. I will check. I was running the batter down often when adjusting the sunroof.

I cranked it over and it fired up but barely from a low battery, directly after, the fan wouldn't come on.

I will check the strip fuse. I wonder if I damaged the CCU with the low voltage.

__________________
Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)