1998 500SL is there a way to test the blower relay to see if it is the problem. All fuses are ok. The relay has four wires . If we ground the blue wire ,on the relayto the black wire, on the relay the blower will come on. If I put a meter on yellow wire, and turn the speed control of the fan and turn it up to hight .It read 6 volts. the red wire reads 12 volts, the black is a ground.
The fan will not come on any setting (air, hear ect) does this sound like a bad relay switch or something else. thanks Linda