1983 mercedes 300d power windows will not operate. I there a relay or something i can check? the fuses are good but i cannot measure any voltage at the fuse.

Bad relay more then likely .
Power Window Operation
The power window system operates under the control of the accessory delay relay. The instrument cluster module (ICM) grounds the relay coil to provide power to the power window system & the radio .

Symptom Chart Condition Possible Sources Action

• All power windows are inoperative

• Fuse(s).
• Circuitry.
• Instrument cluster module (ICM).
• Accessory delay relay.
• Driver window control switch.

• Go To Pinpoint Test A .

The first step to diagnose this problem would be to hook up a factory scan tool an check for DTC'S - diagnostic trouble code's in the ICM . If no codes do pin point test A
Pinpoint Test A: All Power Windows Are Inoperative
Normal Operation Under normal operation the instrument cluster module grounds the accessory delay relay through circuit 1004 (LB/RD). Power is sent to the driver window control switch through circuit 400 (LB/BK) from the accessory delay relay. The driver window control switch is grounded through circuit 1205 (BK).

Possible Causes
• Fuse(s)
• Open in circuits 400 (LB/BK), 1205 (BK) or 1004 (LB/RD)
• Damaged accessory delay relay
• Damaged CJB
• Inoperative ICM
• Inoperative driver window control switch
• INPOINT TEST A: ALL POWER WINDOWS ARE INOPERATIVE Test Step Result / Action to Take A1 CHECK THE VOLTAGE TO THE DRIVER WINDOW CONTROL SWITCH - CIRCUIT 400 (LB/BK)
  • Disconnect: Driver Window Control Switch C504a.
  • Key in ON position.
  • Measure the voltage between driver window control switch C504a-6, circuit 400 (LB/BK) harness side and ground.
  • Is the voltage greater than 10 volts?
  Yes
  GO to A2 .
  
  No
  GO to A3 . A2 CHECK THE GROUND TO THE DRIVER WINDOW CONTROL SWITCH - CIRCUIT 1205 (BK)
  • Key in OFF position.
  • Measure the resistance between driver window control switch C504a-2, circuit 1205 (BK) harness side and ground.
  • Is the resistance less than 5 ohms?
  Yes
  INSTALL a new driver window control switch. REFER to Window Control Switch in this section. TEST system for normal operation.
  
  No
  REPAIR the circuit. TEST the system for normal operation. A3 CHECK THE ACCESSORY DELAY RELAY
  • Key in OFF position.
  • Disconnect: Accessory Delay Relay.
  • Carry out the accessory delay relay component test. Refer to Wiring Diagrams Cell 149 for schematic and connector information.
  • Is the accessory delay relay OK?
  Yes
  GO to A4 .
  
  No
  INSTALL a new accessory delay relay. TEST the system for normal operation. A4 CHECK THE POWER TO THE ACCESSORY DELAY RELAY
  • Key in ON position.
  • Measure the voltage between ground and accessory delay relay socket pin 85 and pin 30 harness side.
  • Is the voltage greater than 10 volts?
  Yes
  GO to A5 .
  
  No
  REPAIR the power supply circuit or central junction box (CJB). TEST the system for normal operation. A5 CHECK CIRCUIT 400 (LB/BK) FOR AN OPEN
  • Key in OFF position.
  • Measure the resistance between driver window control switch C504a-6, circuit 400 (LB/BK) and accessory delay relay socket pin 87, circuit 400 (LB/BK) harness side.
  • Is the resistance less than 5 ohms?
  Yes
  GO to A6 .
  
  No
  REPAIR the circuit. TEST the system for normal operation. A6 CHECK CIRCUIT 1004 (LB/RD) FOR AN OPEN
  • Disconnect: Instrument Cluster Module (ICM) C220a.
  • Measure the resistance between accessory delay relay socket pin 85, and ICM C220a-5, circuit 1004 (LB/RD).
  • Is the resistance less than 5 ohms?
  Yes
  INSTALL a new ICM. REFER to Section 413-01 . TEST the system for normal operation.
  
  No
  REPAIR the circuit. TEST the system for normal operation
• If you don't understand any of this , your best bet mite be to have a qualified repair shop look at it .

Check the connector and wiring on the driver's side door window switch module.

check the voltage at battery with car off. it should be at least, 12-13 volts. then start the car. if alternator is charging it should read at least 13.5-14.2 or better. to test and see if alternator is ok. remove negative cable to battery while running. if car does not quit its ok, if it does its bad or you have a wiring problem. this is how I check for a bad battery as well as above! hook volt meter to battery, turn on headlights with car off. if it drops way down battery is bad. check all fuses and ground wires to charging system if need be.

You said you checked for power, but did you check for ground? Window motor circuits need BOTH to operate.

There is a junction block about 6 inches in front of the battery on the fender, there should be battery voltage on the big wires. The small wire is the starter solenoid. Front the junction block, the power goes to the light switch then to the ignition switch.

Good Luck

Chet

Most likely switch as each window does not have its own fuse. If its not the switch it may be the regulator/motor has gone out.

undo the bolts that hold the alternator on its bracket there stoping you pulling the alternator off the belt
when you have the new belt on pull belt tight and nip up all the bolts again

Check the center lower pulley harmanic balancer if center of pulley spinning, could be broken and just spinning on outer pulley hub.Hope this was very helpful Good luck

This is a common problem, but I've never seen a window regulator go bad in a Mercedes, the problem is probably the switch, you can remove both switches from the consul, and plug in the other side to roll the window backup, you will need to disassemble the switch that does not work and clean all the garbage out of the, and it will work again I've done it to my Mercedes

If you indeed check and veify the fuses are good than you need to check the relay(s) that control the system. These should all be located in the power box located drivers side firewall under the hood (Black cover). You may need to reference your manual for the relative position of the affected componenets (Fuse, Relay, etc...)