The climate control on my 1999 C230 has stopped working. Manual dial system not the digital display.

It happened after I replaced the windshield wiper motor (due to ice holding wiper and plastic gear inside motor was stripped). Not sure if this is related or just a coincidence.

The blower runs when power is connected to it directly OR when the REST button is depressed (red light on). This is the way I am getting heat right now, until I figure this out.

When the REST button is engaged the switches illuminate, when the REST button is off the switch lights are off.

I have constant power to the Blower Regulator and power at the blue wire and red wire connected to the regulator.

When I connect a test light to a ground and touch the body of the Regulator the test light goes on? Is this normal?

I have tried another regulator and get the same thing.

Is there a way to figure out if the climate control switch module is bad?

The EC button does not illuminate when pressed, but the heat was working fine anyway until 2 days ago.

I have taken it out and inspected it but everything (circuit boards) look ok, no smell, clean, etc...

anyone home?

This is a ground control circuit = all control is on the ground side.

Best guess:

You lost the ground connection or the blower regulator failed.

.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

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