wiper motor blowing the fuse

[jskinner96]

Wipers were working okay but slow so I took them apart and cleaned them all up. Put it all back together and it blows the fuse when I turn the key on. I've read the other posts on here and tried everything but it's still blowing fuses. I can't see where there are any nicked wires. Could it be the way I put the motor back together? Seems to be right and really just one way to go back together. Any suggestions would be greatly appreciated.

[18Fiatsandcounting]

I'm not familiar with an '85.5 spider, but if it's like the earlier ones, there is an electrical connector underneath the hood cowl. The connector for the wiper motor. Disconnect that connector, and see if the fuses still blow. If they do, then your problem is not the motor. If they don't, they your problem is the wiper motor.

I vaguely seem to recall that you could put the wiper arm rotors back in a certain orientation that would lock up in a certain position, and that would definitely jam the motor and blow the fuse. Perhaps that's your issue. So check that each wiper arm shaft isn't working against the other, as they go through their full range of motion.

-Bryan

[spider2081]

Put it all back together and it blows the fuse when I turn the key on

if the 85.5 Spider has more that one connector at the wiper motor are you sure they are plugged into the correct mating connectors.
When you say you disassembled do you mean you opened the actual electric motor itself ??

[jskinner96]

I did open up the motor itself and took the plastic piece off that covers the wiring just to make sure it was all in good shape. I wasn't positive that the connectors were plugged into the correct ones and I can't make sense of any of the wiring diagrams (don't seem to show the color wires I have) so I tried both ways and it blew. There are two 2 pin and 1 one pin. I then tried to unplug each one to see narrow down which is blowing and the one with the red end from the motor (light blue/white and blue/black) that plugs into the black end (light blue/white and blue/black) is the one that blows the fuse. If it's unplugged but the other two are plugged in it doesn't blow. The other 2 pin from the motor is has a white end (grey and blue) that plug into a black end (light blue/red and grey). Since the motor was working okay before I took it apart and I've tried the wiring both ways it almost seems like I may have disturbed something in the motor itself that's making it blow the fuse. But I've inspected the motor quite a bit and tried to take it apart and put it back together several times and it seems like it's put together correctly with no broken wires.

[spider2081]

I think when the 2 connectors having the light blue/white and light blue/black wires are mated that is correct. That leaves the cars connector having gray/yellow and light blue red connector to mate with the wiper motor connector having I believe red and gray wire.

When you removed the black plastic cover did you see an exposed switch that is activated by the cam on the nylon drive gear? That switch switches a ground to stop the motor in the park position. It is not too unusual for this switch to overheat and its contacts melt the plastic retaining them, creating a short.

The fact that the fuse blows when the ignition switch is turned on and the wipers are not leads me toward the park switch.
Have you separated the linkage from the motor to see if the fuse blows?

[jskinner96]

When you removed the black plastic cover did you see an exposed switch that is activated by the cam on the nylon drive gear?

I'm not real sure to be honest. I'm a visual learner so when I get home I'll be looking at that as I re-read your comment about it. I do have the linkage removed and have tried the motor just by itself but it still blows. There was a small spring connected to a white plastic piece that went down in a small hole. I kept looking at that and never could really figure out what it's purpose is. But when I pulled it apart that spring was completed rusted and it just fell apart. I searched my entire shop for a replacement spring that size and then realized it's the same spring as inside an ink pen with the clicker top. So I added that spring back on and cleaned up all the crap out of that area but that didn't help. And I still don't know what that spring and white piece even do?

[spider2081]

And I still don't know what that spring and white piece even do?

I believe you are talking about the "V" shaped nylon piece. the motor armature center shaft is the worm gear that drives the large white nylon gear. I believe he spring and wedge limit the end play of the worm gear and shaft. The force required for the large white gear to begin turning would would wear its teeth if the worm gear were not allowed to move slightly end wise when the motor starts.
I have seen some earlier wiper motors that do not have the wedge so I think it a product improvement.

[jskinner96]

I have the motor working and not blowing the fuse now. Thanks to Richard for that electrical diagram. I think when I put the housing on it was pulling the shaft back out a little so it wasn't set in there correctly. I was able to put a screwdriver in the area where the shaft meets the white wheel with the teeth and hold it in place as I put the housing back on. With the wipers raised up off of the glass the motor spins perfectly and moves the wipers round and round. As soon as I place the wipers on the windshield they go nowhere and you can hear the motor going but just some grinding noise like that white wheel with the teeth isn't engaging. I inspected the teeth on the white wheel and they seem good but that white wheel does have some small cracks in the center of it. Not sure if that would make it not work at all. But something isn't engaging strongly enough and moving the wipers. All the linkage is greased and moves great.

[18Fiatsandcounting]

It kinda sounds like the outer portion of that white gear might be spinning around on its hub, or on the center shaft that drives the linkage to the rotor arms. There's enough friction to keep things moving when the wiper blades don't have any resistance, but when they do, the motor turns but the shaft coming out of the motor doesn't.

I just rebuilt the washer motor on my '69, which I realize is nowhere near the model year of your car. However, I noticed that the inner hub of the white gear (yellow in my case) is not entirely cylindrical; rather, it is sorta square. If the square portion of the shaft end isn't totally inserted into the squarish hole in the gear, it could be slipping. Take off the cover to the wiper motor along with the black plastic block that has all the wires to it, and then remove the nut and washer at the end of the shaft. Make sure the shaft is fully seated in the white gear.

-Bryan

[jskinner96]

I've checked the white wheel thoroughly and all teeth are good and it spins like it should without slipping even when I put some good pressure on it from the side that hooks to the linkage. I think the issue is that the worm gear fro the motor is not inserting all the way up like it should and I can't seem to figure out what the issue is. There are also some grooves in that gear that look like it should be inserted further for them to make contact but they are outside of the shaft not making contact with anything. I haven't figured out the picture posting yet but the links are below that show how far I can insert the worm gear and the grooves on that gear that aren't touching anything when I push it through.

https://imgur.com/a/I97zIvu
https://imgur.com/a/I97zIvu

[18Fiatsandcounting]

Are these the right pictures? The links take me to 2 pictures, one of which I can't really tell what it is, and the other is a picture of the motor armature contact windings, which are on the opposite end of the motor from the white gear.

Sorry I can't be very helpful, but it's not clear to me what exactly we're dealing with here.

-Bryan

[jskinner96]

Thanks Bryan, I got that "C" ring off and got to the white wheel. It likes it was seated correctly so I put it all back together firmly. without the worm shaft inserted I can spin it and when I hold friction on the part that goes to the linkage it becomes harder to turn the wheel. When I put the shaft in it connects just right to the wheel and I can spin that and make it turn as well. Applying hard pressure on the part that goes to the linkage makes it harder to turn but nothing slips. I put it all back together making sure the shaft didn't slip down when I put the housing with the magnet on it and put it back on the car. Same result. I lifted the cowl and applied a small bit of pressure on the linkage and it stops spinning. The only thing left that I can think of is the motor is bad and too weak? Any easy way to test the motor to see if it's bad? At this point I'm ready to just buy a new one anyway. I could have marked about four other things off my Spider to-do list in the amount of time I've spent on this damn wiper motor. I really appreciate all the help though. Jeremy

[18Fiatsandcounting]

Jeremy, this one has me stumped, and it sounds like the best course of action might be to buy a new wiper motor.

If you buy a new motor and want to get rid of (sell) the old one for parts, let me know.

-Bryan

[jskinner96]

Thanks again Bryan. I'm stumped as well. I looked at several other pictures that show the armature inserted in between the brushes and they seem to insert much deeper than mine. Below is a pic of mine and the next pic is one I found of someone else's. I can't push it in any further though because there's a cap at the top that will push up a little as you push the shaft up. I even thought maybe something fell in the hole that the shaft goes in and was keeping it from going all the way up. But I blew it out and there's nothing in there. I think these brushes not making contact all the way around may have something to do with my issue but for the life of me I can't figure out why it won't insert more. I'll definitely let you know if I'm not going to need this motor.

https://imgur.com/a/sZdnabo
https://imgur.com/oHnSD2f

[18Fiatsandcounting]

It does look like the rotor part of your wiper motor isn't inserting all the way into the back cap, as the brushes don't look like they're riding on the center of those copper winding contacts. If that's the case, this could cause the other end of the rotor (the worm gear part) to not be positioned on the white gear where it should be.

Can you take out the two carbon brushes and see what the issue might be? I seem to recall on my wiper motors that the non-gear end of the rotor inserts into a little bearing in the cap, and it has to be inserted right or it won't go all the way in. The "little bearing" wasn't a true bearing in the sense of ball bearings with a race, but rather just a collar made of brass or another softer metal. Again, going by recollection here.

-Bryan