Windshield wipers not working ,I' don't know what to troubleshoot
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Make sure you are getting good ground. The motor grounds through one of the bolts and a grommet strap. If you do not have a good low resistance connection between chassis and wiper motor base it will not work.
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The wiper motor receives its power through the ignition switch accessory circuits. Do other things like radio and heater blower function? If so, it's not the ignition switch.
The windshield wiper switch has a built-in circuit breaker and if it has failed will not supply voltage to the wiper motor. Check for voltage on the red wire at the connector on the wiper motor, it should be hot all the time. If it has battery voltage the circuit breaker is OK.
The white wire to the motor should have battery voltage in the switch low position, and the dark blue with orange stripe wire when in the high position.
The windshield wiper switch has a built-in circuit breaker and if it has failed will not supply voltage to the wiper motor. Check for voltage on the red wire at the connector on the wiper motor, it should be hot all the time. If it has battery voltage the circuit breaker is OK.
The white wire to the motor should have battery voltage in the switch low position, and the dark blue with orange stripe wire when in the high position.
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I put together a few snippets of schematic info for a 1973 Mustang windshield wiper circuit. It ought to be the same as found in 71-72 Mustangs, and even earlier models in general. The wiper switch circuitry does show it has an internal circuit breaker. But, it also shows Fuse #1 is part of the wiper (washer motor) circuitry. Attached is a PDF file showing the wiper circuit, another file showing fuse block detail, and a third file with a graphic drawing and photo of the fuse block. In the graphic PDF file the description of what Fuse #1 is not as complete as I feel it should be. That is corrected in the PDF file covering the Fuse Block schematics, which shows the more complete circuit protections from the Fuse Block.
There is attached PDF file that shows the fuse block circuitry details also show the various circuits fed via the fused side of the fuse block. Circuit 296 is fed by Fuse #1, and it is later found to be used for the for the windshield washer circuit. Looking at the schematic at grid location B-61 does cause me to concur Fuse #1 is for the windshield washer motor circuit, whereas indeed the schematic does show the internal circuit breaker in the wiper switch is what actually protects the wiper motor circuitry (although in the next paragraph I do mention Circuit 37 which is protected by a Fusible Link). Also, the schematic shows two different wiper switches, an intermittent switch, and the regular two speed switch. Only one of the two switches will be in use on any particular car, but both are shown in the schematic.
Circuit 297 is what feeds the circuit breaker protected current to the wiper switch. At grid location B-59 you will see how Circuit 297 is sent off in different directions at splice S-302. The part of what feeds Circuit 297 at Splice S-302 can be traced to the ignition switch at grid location C-57. What feeds the very beginning of Circuit 297 through the ignition switch is Circuit 37, a Yellow wire that can be traced back to Fusible Link mounted to the larger positive post of the Starter Motor Relay. So, in essence the complete circuit is protected by a Fusible Link in Circuit 37, and by the internal circuit breaker inside the wiper switch fed by the one end of Circuit 297 used for the windshield wiper circuit.
I hope this helps. If you need more info just let me know via this post's thread, or at [email protected]
There is attached PDF file that shows the fuse block circuitry details also show the various circuits fed via the fused side of the fuse block. Circuit 296 is fed by Fuse #1, and it is later found to be used for the for the windshield washer circuit. Looking at the schematic at grid location B-61 does cause me to concur Fuse #1 is for the windshield washer motor circuit, whereas indeed the schematic does show the internal circuit breaker in the wiper switch is what actually protects the wiper motor circuitry (although in the next paragraph I do mention Circuit 37 which is protected by a Fusible Link). Also, the schematic shows two different wiper switches, an intermittent switch, and the regular two speed switch. Only one of the two switches will be in use on any particular car, but both are shown in the schematic.
Circuit 297 is what feeds the circuit breaker protected current to the wiper switch. At grid location B-59 you will see how Circuit 297 is sent off in different directions at splice S-302. The part of what feeds Circuit 297 at Splice S-302 can be traced to the ignition switch at grid location C-57. What feeds the very beginning of Circuit 297 through the ignition switch is Circuit 37, a Yellow wire that can be traced back to Fusible Link mounted to the larger positive post of the Starter Motor Relay. So, in essence the complete circuit is protected by a Fusible Link in Circuit 37, and by the internal circuit breaker inside the wiper switch fed by the one end of Circuit 297 used for the windshield wiper circuit.
I hope this helps. If you need more info just let me know via this post's thread, or at [email protected]
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