1990 Mercedes-Benz 420SEL Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 1990 Mercedes-Benz 420SEL
Never overpay. Check prices with our estimator
Verified by mechanics, reported by drivers like you
Ask a mechanic in our community
1990 Mercedes-Benz 420SEL ProblemsBad Switch/Blower Motor Resistor Assembly May Cause Inoperative Heater Blower Motor
Other than a defective motor, a bad switch or blower motor resistor assembly can cause an inoperative heater blower motor.
It is not uncommon for the idle air compensator to get stuck in one position, resulting in the engine idle speed (rpm) being too high or too low. Replacement of the failed compensator may be necessary to correct this concern.
A refrigerant leak may develop from one or more of the AC hoses. Proper leak detection procedures should be followed if refrigerant loss in encountered. Replacement of any leaking hoses will we required to restore proper AC operation.
1990 Mercedes-Benz 420SEL QuestionsI have no heat or a/c blower works, and I have replaced several parts already (2 answers)
I have replaced the climate control switches, a/c compressor, mono valve, thermostat, I need help and or cost for repairs
The economy needle has gone from black all the way to red.