wiper motor question

[newstang 388]

when i turn off the switch for the wipers it stops in place, it does not return home. is this the motor or switch?

 

[fvike 173]

I think it stops where it is if stopped on the way up. And goes to park if stopped on the way down.

[69RavenConv 286]

The wiper shaft has a cam that opens the circuit when it gets to the home position. The dashboard switch is in parallel with the cam switch - if the dash switch is ON there is electricity flowing to the wiper motor all the time, but when it's off, electricity stops when the cam opens the switch in the cowl. It sounds like your cam mechanism or the associated contacts may be open all the time.

 

[newstang 388]

so i should be looking at the motor then or the transmission on it. or just change it out.

 

 

[Mach1 Driver 560]

The wiper motor circuit is real science. If the motor runs, then stopping it in the correct place is a function of two switches- one in the dash mounted wiper switch, and the other in the motor. It could be a problem with the wiring too. To get it to stop quickly and in the correct place (they call it parking) they used a technique termed "dynamic braking". It relies on the fact that a DC permanent magnet motor can also become a generator if power is removed and the shaft is still turning. As a generator it produces a voltage opposite to that which would turn it in that direction- if it were a motor. So first they slow to motor to the slow speed, because its easier to stop when its going slower, and then they connect the ends of the motor's coil together. It tries to reverse itself and stops very quickly in the process. You can follow the process step by step here:

 

[newstang 388]

14 minutes ago, Mach1 Driver said:

The wiper motor circuit is real science. If the motor runs, then stopping it in the correct place is a function of two switches- one in the dash mounted wiper switch, and the other in the motor. It could be a problem with the wiring too. To get it to stop quickly and in the correct place (they call it parking) they used a technique termed "dynamic braking". It relies on the fact that a DC permanent magnet motor can also become a generator if power is removed and the shaft is still turning. As a generator it produces a voltage opposite to that which would turn it in that direction- if it were a motor. So first they slow to motor to the slow speed, because its easier to stop when its going slower, and then they connect the ends of the motor's coil together. It tries to reverse itself and stops very quickly in the process. You can follow the process step by step here:

 

thanks!

 

[newstang 388]

I forgot to mention that this has the delay module and switch from a bronco. it all worked fine till a few months ago. I guess ill start with the process of elimination.

 

BY THE WAY,,,,, is it me or do all the windshield wipers sound like nails on a chalkboard?

 

[Mach1 Driver 560]

3 minutes ago, newstang said:

I forgot to mention that this has the delay module and switch from a bronco. it all worked fine till a few months ago. I guess ill start with the process of elimination.

 

BY THE WAY,,,,, is it me or do all the windshield wipers sound like nails on a chalkboard?

 

Nails on a chalk board? I hadn't noticed that- don't forget to add water. My wire diagram says that intermittent wipers were an option in 69. The Windsheild Wiper Governor 17C476 (pause control) appears to be a separate box with a transistor, diode, cap, resistor network and a relay. The switch is different (17A553) with a variable resistor to set the time relay for the relay. The motor is electrically the same. Without converting it from a wire diagram to a schematic I can't be certain the park feature is exactly the same, but it looks like it might be. The switch seems to use the same plug.

[newstang 388]

2 minutes ago, Mach1 Driver said:

Nails on a chalk board? I hadn't noticed that- don't forget to add water. My wire diagram says that intermittent wipers were an option in 69. The Windsheild Wiper Governor 17C476 (pause control) appears to be a separate box with a transistor, diode, cap, resistor network and a relay. The switch is different (17A553) with a variable resistor to set the time relay for the relay. The motor is electrically the same. Without converting it from a wire diagram to a schematic I can't be certain the park feature is exactly the same, but it looks like it might be. The switch seems to use the same plug.

the blades themselves have always been loud as opposed to any other car I own, perhaps pressure or length?