1991 Mercedes-Benz 420SEL Repair and Maintenance
A guide to problems, costs, maintenance and repair for your 1991 Mercedes-Benz 420SEL
Verified by mechanics, reported by drivers like you
Ask a mechanic in our community
Never overpay. Check prices with our estimator
1991 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.
A rough running motor or lack of power can be caused by a failed distributor cap or rotor, ignition wires (or their resistors), or valve cover gasket leaks. If the valve cover gasket leaks, oil can pool where the ignition wire resistor connects to the spark plug. The resistor can fail and the spark plug may not fire because of a short circuit through the oil.
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.
1991 Mercedes-Benz 420SEL Questionswhere is the rheostat in a 1991 420 sel (1 answer)
something warm up & it wont start
where do I spray starter fuel? how do I find air intake pocket?