Have classic car questions? Ask an Expert.
Hello, a quick way to test the motor is to ground terminal 31 and use a fused jumper wire to supply 12 volts to terminal 53b (high speed) or 53 (low speed) if the motor does work we know to next check the switch/wiring. You can see the wiring diagram HERE just let me know what you find and we can work further if needed.
Thanks for the additional info. With the key on and wiper switch off is there 12 volts at terminal 53A on the wiper motor?
With the key on and wiper switch on high is there voltage on terminal 53b of the motor?
If voltages are present but motor does not move will it move if you ground terminal 31 of the motor?
My apologies for the delay, I'm looking over the diagram and trying to determine why the switch would be working only with power applied to those motor terminals. I cannot say for certain if it's a power lead missing to the switch on 53a of the switch or the intermittent relay. I'm going to open this back up to other experts to see if any of our other guys has some thoughts on isolating the issue in this circuit.
Hi, my name is***** you still need help with this?
A 74 should not have intermittent wipers. How many positions does your switch have? It should just be OFF, speed 1 and speed 2.
Ok, turn the key on and test for voltage at the wiper motor terminals. Let me know which terminals have battery voltage.
Is your wiper switch a push/pull switch or is it mounted on the steering column? Can you send me a clear picture of the wiper motor wiring and of the connector to the wiper motor? Can you also list the wire colors? Once I have all of that I should be able to sort this out for you.