Windshield Wiper Questions
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
Windshield Wiper Questions
I'm working on the wipers on my 72 and I can't get the rebuilt motor to run on the car . I bench tested it before installation and it worked fine . Installed it in the car and it worked . Went to turn on the wipers yesterday and nothing. I tracked the problem down to the small red individual wire that goes into the wiper motor. There is now no power coming from the harness into that red wire. If I hook up a jumper wire straight from the + on the battery to the red wire going into the wiper motor it runs fine on both speeds and parks when I shut off the switch. What I need to know and I can't find it in the schematics is where does the current come from leading into that red wire ? I know there are two electrical switches that operate the wiper door . The one behind the tach and the limit switch on the firewall . Would either of them have anything to do with the power not getting to this red wire on the motor ? The limit switch checks out good . The wiring harnesses are new so I wouldn't expect a problem there and it was working.
Team Owner
Joined: Sep 2006
Posts: 31,218
Likes: 4,305
From: Westminster Maryland
Hi bjk,
Yes, the limit switch on the engine side of the firewall interrupts the flow of current to the wiper motor until the wiper door mechanism's 'arm' has depressed the switch.
The purpose of this switch is to prevent the wipers from starting before the door is FULLY open.
Push the button with your finger to see if that allows the motor to start… hopefully it's just an adjustment of the tiny plunger on the arm that needs to be done.
Regards,
Alan
Yes, the limit switch on the engine side of the firewall interrupts the flow of current to the wiper motor until the wiper door mechanism's 'arm' has depressed the switch.
The purpose of this switch is to prevent the wipers from starting before the door is FULLY open.
Push the button with your finger to see if that allows the motor to start… hopefully it's just an adjustment of the tiny plunger on the arm that needs to be done.
Regards,
Alan
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
Hi bjk,
Yes, the limit switch on the engine side of the firewall interrupts the flow of current to the wiper motor until the wiper door mechanism's 'arm' has depressed the switch.
The purpose of this switch is to prevent the wipers from starting before the door is FULLY open.
Push the button with your finger to see if that allows the motor to start… hopefully it's just an adjustment of the tiny plunger on the arm that needs to be done.
Regards,
Alan
Yes, the limit switch on the engine side of the firewall interrupts the flow of current to the wiper motor until the wiper door mechanism's 'arm' has depressed the switch.
The purpose of this switch is to prevent the wipers from starting before the door is FULLY open.
Push the button with your finger to see if that allows the motor to start… hopefully it's just an adjustment of the tiny plunger on the arm that needs to be done.
Regards,
Alan
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
Found the problem guys. I was able to track down where the current was coming from and it led to a defective intermittent wiper override switch. The route of the current is pretty simple if you have a good schematic . I finally found a schematic just on the wiper system. For future search use maybe it can help someone else . The current starts at the fuse link , goes through the wiper override switch ,then out to the limit switch. From there it goes to the plug on the small red wire that leads into the wiper motor. Hope this can help someone else in the future.
Team Owner
Joined: Jul 2006
Posts: 22,162
Likes: 4,171
From: Kannapolis NC
Found the problem guys. I was able to track down where the current was coming from and it led to a defective intermittent wiper override switch. The route of the current is pretty simple if you have a good schematic . I finally found a schematic just on the wiper system. For future search use maybe it can help someone else . The current starts at the fuse link , goes through the wiper override switch ,then out to the limit switch. From there it goes to the plug on the small red wire that leads into the wiper motor. Hope this can help someone else in the future.
Thread Starter
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
That's correct, look at the wire coded red in this Willcox diagram. The power comes from the battery, through the wiper override under the dash, then to the wiper door switch, then to the wiper motor red.
Attachment 47885410
Attachment 47885410
