1977 Gran Fury wiper woes

[Manfred1]

Ok I'm trying to figure out a mild electrical fire that may be the result of a bad decision. Its a 3 speed wiper motor and when I got the car 10 years ago they did not work. The switch has a strange "Borg" looking ( heat sink?) that sits ontop of the switch. Its a rectangular block with a few thin wires going into the switch. So, I replaced the non working switch years back with a junkyard one that was identical. Viola!! They worked although it was touchy ( had to tap the switch just right) and only 2 of the speeds functioned, plus it had difficulty "parking". A month back they switch would no longer park and only barely worked with a wipe or 2 before freezing up. So...I di through my stash and find a switch w/o the "Borg" box ( a 2 speed switch I presume), it plugged in the same and the wipers promptly parked. It was dry out so I did not run it through its paces. Drove it for 2 days, all good and then the blue/pink wire caught fire and scared me 1/2 to death. This car is my daily driver. I checked the plug and the "hot' wire was still hot, no fuse blown. The blue/pink is a 'delivery" wire. Of course this wire is deeply embodied in the harness so I'm going to build a new sub harness so no stress is put on the main.

Could the install of a 2 speed switch on a 3 speed motor cause this? Is all grounding through the switch body? What is the "Borg" rectangular box ontop of the 3 speed switch ? Can I trust the wiper motor? Blue/pink wire function? The rest of the sub harness is all good?

Thanks in advance

 

[1970FuryConv]

Ok I'm trying to figure out a mild electrical fire that may be the result of a bad decision. Its a 3 speed wiper motor and when I got the car 10 years ago they did not work. The switch has a strange "Borg" looking ( heat sink?) that sits ontop of the switch. Its a rectangular block with a few thin wires going into the switch. So, I replaced the non working switch years back with a junkyard one that was identical. Viola!! They worked although it was touchy ( had to tap the switch just right) and only 2 of the speeds functioned, plus it had difficulty "parking". A month back they switch would no longer park and only barely worked with a wipe or 2 before freezing up. So...I di through my stash and find a switch w/o the "Borg" box ( a 2 speed switch I presume), it plugged in the same and the wipers promptly parked. It was dry out so I did not run it through its paces. Drove it for 2 days, all good and then the blue/pink wire caught fire and scared me 1/2 to death. This car is my daily driver. I checked the plug and the "hot' wire was still hot, no fuse blown. The blue/pink is a 'delivery" wire. Of course this wire is deeply embodied in the harness so I'm going to build a new sub harness so no stress is put on the main.

Could the install of a 2 speed switch on a 3 speed motor cause this? Is all grounding through the switch body? What is the "Borg" rectangular box ontop of the 3 speed switch ? Can I trust the wiper motor? Blue/pink wire function? The rest of the sub harness is all good?

Thanks in advance

Probably not a problem with your wiper motor
Check continuity and resistance on every wire in the wiper motor wire harness. In Colorado, when wipers freeze against the windshield, the wiper motor can draw a lot of current to try to break the wipers loose. This burns up your wiring harness from the wiper switch to the wiper motor.
Buy a new switch on eBay. Heavy current draw burns up internals on the switch. The junkyard switch has the same problem because it is from the same location.
Most importantly, break the wipers loose by hand from now on (You probably already know this)

 

[Manfred1]

I already have a NOS switch, the correct version.

Thanks

 

[Manfred1]

I'll try the reroute and new switch this week. I bet the frozen wiper is part of the story, especially with the hidden location that loves to hold ice and water.

 

[Manfred1]

So I'm still baffled on how to proceed. I tested the NOS switch with an ohm meter and discovered to my horror that even in the off position power is sent into the harness via the blue wire that caught on fire. I only the fat red wire is hot and the switch delivers signal to the other wires once activated. Why in the world would that blue wire be hot with the switch off. I checked against a known good used switch as well as the NOS one. I'm not a novice at electrical work, but the factory wiring diagram is beyond my comprehension. I'm tempted to just force a new circuit and bypass all the "park" , multiple speed , and wiper washer functions. The wiper motor has a ballast resistor on in as well. Its my daily driver and this fire has really freaked me out. Everything else still works and it never blew any fuses. luckily I caught it while driving. Feeling defeated on this issue

 

[1970FuryConv]

So I'm still baffled on how to proceed. I tested the NOS switch with an ohm meter and discovered to my horror that even in the off position power is sent into the harness via the blue wire that caught on fire. I only the fat red wire is hot and the switch delivers signal to the other wires once activated. Why in the world would that blue wire be hot with the switch off. I checked against a known good used switch as well as the NOS one. I'm not a novice at electrical work, but the factory wiring diagram is beyond my comprehension. I'm tempted to just force a new circuit and bypass all the "park" , multiple speed , and wiper washer functions. The wiper motor has a ballast resistor on in as well. Its my daily driver and this fire has really freaked me out. Everything else still works and it never blew any fuses. luckily I caught it while driving. Feeling defeated on this issue

Hi Manfred
Pictures of the Wiper switch and the Borg mechanism on top would help.
Have you gone on www.mymopar.com to download shop manual with wiring diagram?
Don't know why a NOS switch would send power to the wiper motor in OFF position. How did you determine this?
Thanks Ben

 

[Manfred1]

I'll get pictures and look at the down load for the shop manual. I determined the switch function with an ohm meter and a test light. Thanks very much for the offer to help

 

[1970FuryConv]

I'll get pictures and look at the down load for the shop manual. I determined the switch function with an ohm meter and a test light. Thanks very much for the offer to help

So you moved the switch to OFF and had continuity from the NOS switch's power input socket/blade to the switch's socket/blade for this blue output wire?
If so, we need to know if the blue output wire controls the Park function of your 77 Gran Fury

 

[Manfred1]

That would be my guess, its a unique expression of the switch. So maybe the wiper motor fried internally and grounded out that circuit? That could explain the ballast resistor, it stays hot but at low voltage while in stand by mode? I'll get pics tomorrow

 

[Manfred1]

OK here is a picture of the switch. I'm guessing the power on in the off position reverses the polarity for the park function

 

[1970FuryConv]

OK here is a picture of the switch. I'm guessing the power on in the off position reverses the polarity for the park function

View attachment 697086

View attachment 697087

View attachment 697089

I think you're right.
Have you used an ohmmeter to check for cross continuity in the wires from the switch to the wiper motor? Disconnect both connectors. Start with one wire at wiper switch connector. Check all connectors at wiper motor? Should be only continuity for the wire that you have the probe on at the wiper switch connector
Does the blue wire control park? Does disconnecting it disable park?

 

[traintech55]

You need to lay your hands on the electrical schematic for the wipers. If I remember correctly, the three speed system always has a hot feed to the motor, and all other functions are controlled by different grounds.

 

[traintech55]

I remembered I have the prints you need. The bottom schematic is for the three speed wipers, the top is for the two speed. The print starts on page 27 and ends on page 28. Good Luck. Bill

 

[Manfred1]

Thanks so very much! I think I can move forward