Hi,

I have no heat on my 1990 W124 2.5TD. Sometimes the heater blower motor does come on after a very long time (20 minutes) and sometimes it does not come on at all. It seems that I hear some ticking sound in the dashboard area.

When the heater blower motor comes on sometimes, the heat seems to work. I changed the heater valve and auxillary water pump last year.

Anything I should check? I appreciate any guidance. Thanks.

Best Regards,
Louis

Yes, power (12V) to the blower motor & to the blower motor electronic regulator.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The blower motor and regulator were changed last year as well. The heat and A/C did work for a while and then it became inconsistent.

The A/C does not work either since the blower motor does not come on.

What else could it be?

Check for power at fuses, blower fuse is on drivers shock tower. (30A strip fuse)

Fuse for climate control is #7.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks for the recommendation. I did replace the fuse and it worked for a few days and then I started to get the problem where the blower motor does not come on after maybe 20 - 30 minutes of the car being on.

It is a very inconsistent problem that is impacting both Heat and A/C functions. Could it be a bad CCU? Thanks.

Could be the pushbutton unit. Strange things like that can happen when they fail. I need to do mine soon!

__________________
Streetside: 1987 Mercedes 300E Petrol Blue/Green
2014 Ford Mustang Grabber Blue
1999 Ford Ranger Green

Dockside: 1968 Eltro 17
1985 Silverton 34C

My 1995 e320 wagon was exhibiting the same symptoms; the fan would come up after 20 minutes of driving. It got worse for a week, and then the fan stopped. See my post of two weeks ago. The brushes were very worn, and I suspect they were not making contact, but did so after rattling around for a few minutes.