Other than a defective motor, a bad switch or blower motor resistor assembly can cause an inoperative heater blower motor.
Car problem reports
Problem with your car? See what our experts say or submit your own.
Most reported 1990 Mercedes-Benz 500SL problems
High mileage vehicles may develop a transmission fluid leak from one or more of the oil seals.
As vehicles age, various problems may develop with the hard and soft tops. If problems are encountered, it would be recommended to have a technician familiar with these tops perform the diagnoses.
The bushings for the shifter lever wear out to the point where they break and fall out. This causes excessive movement (loose feel) in the shifter lever and a clanging-type noise when changing gears.
The engine wiring can degrade because the insulating material falls off leaving the bare wire exposed. This can cause many problems depending on which wires are exposed and what they touch.
A faulty mass air flow (MAF) sensor can cause erratic/rough engine operation and fuel economy issues. Since this sensor measures the actual amount of air entering the motor, when it fails, the engine control module (ECM) takes the wrong information and delivers incorrect volumes of fuel to the cylinders.
A coolant leak may develop form the Radiator due to degradation of its plastic components. Replacement of the failed radiator will be necessary.
A refrigerant leak may develop from one or more of the following AC components: AC compressor, hose manifold for the compressor, or the evaporator core. The loss of refrigerant can cause poor AC performance. Our technicians tell us that proper leak diagnoses should be performed in order to determine the cause of any refrigerant loss.
The head lamp wipers are easily damaged, especially by automatic car washes.
Oil feed tubes break and fall into the crankcase (engine) and the tappet becomes noisy (ticking), resulting in degraded idle quality. Our technicians recommend replacing all of the tubes at the same time, broken or not.
The tie rod ends, idler arm, and/or drag link components of the steering linkage may wear prematurely. Please keep in mind the wheel alignment should be checked and adjusted when any of these items are replaced.
The electronic throttle assembly may suffer an electrical failure. It is often cheaper to send the valve to a service center for repair that to purchase a new part.
Ports in the cylinder head related to the emissions air injection and EGR systems can clog; the cylinder head should be removed and the ports cleaned.