1. Buckeye601

    Buckeye601 Puttering Along

    This is probably a long shot, but does anyone have a spare 6v front wiper motor available from a parts car or otherwise that they would be willing to sell?

    My motor appears to be bad (it is getting power but does not move the wipers so I presume it is bad) and I was planning to order one from Trabantwelt.de but that item seems to have been removed from their site recently, though it was available for 30 Euros a few weeks back. I was waiting to place another order until I knew if I needed other parts for my brakes, but perhaps I should have ordered more quickly.

    I would be willing to pay a reasonable price for the part and shipping. I am located in the US so it would be preferable to find someone here with one, though I am open to international shipping if needed. I presume they are much easier to find in Europe than here.

    For reference, since there seem to be some different types over the years, I uploaded a couple of pictures to show what it looks like, one with the cover on (it is in the upper right corner of the picture) and one with it off.

    Attached Files:

  2. turbofiat124

    turbofiat124 Premium Member Forum Donor

    Before I bought a new one, I'd remove it from the car, spray some PB blaster on the brushes and stick a pair of Vice Grip pliers on the shaft and try turning it by hand. I'd say the brushes are stuck to the commutator from sitting and just need a little persuasion.

    Just about every spring when my father opens up his pool, this pump motor is always seized up. It makes a hum but does nothing.

    I have to pull the motor out of the pump housing, grab the impeller with a large pair of adjustable pliers and turn barely turn it to break it loose where it seizes up over the winter.
    Buckeye601 likes this.
  3. Buckeye601

    Buckeye601 Puttering Along

    Thanks for the suggestion. It does not make any noise and there is no other evidence that it is trying to turn, but it may just be stuck fast. I sprayed electrical contact cleaner on it and tried to free the brushes without success. I did not remove the motor and try turning the shaft by hand however. I suppose it makes sense to see if I can get it to turn, and perhaps use a stronger solvent if needed since doing so won't make it work any less.

    I found the troubleshooting procedure below on trabitechnik.com (I posted the figure referenced as an attachment). As mentioned above, I tried this to no avail, but maybe it requires a different solvent (or some shaft turning) to break free.

    If voltage is present at the wiper motor (terminal 54) and the ground connection (terminals 31 and 31 b) is functional and the motor still does not run, the carbon brushes usually stick in
    their holders. To remove this fault, the cap of the wiper motor is removed and both carbon brushes are briefly lifted and released several times (Fig. 6-17). They are usually passable again and then lie on the collector of the anchor properly.

    I believe the caption for the picture states:

    The carbons of the wiper motor can be made to work

    Attached Files:

    Last edited: Sep 30, 2019
  4. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I've taken apart, cleaned and repacked two speed Bosch and Magnetti Marelli wiper motors and put them back together. I've never taken a Trabant wiper motor apart. From the photo

    If you can't turn it using some pliers, you could removing the covers where the bearing sits on the end of the shaft, spray some PB Blaster between the brushes and commutator and try pulling it out to see if you can free it up. Being a 1 speed motor, there should just be two brushes. So it's easier than trying to pull three sets of spring loaded brushes back when sliding the commutator shaft back into the stator housing.

    Judging from the photo you posted, it doesn't look like the brushes are worn. That's usually what goes wrong with an electric motor.

    The shellac that coats the copper wire used on the rotor could have degraded and fallen off. Kind of doubt it. I bet the brushes are just stuck to the commutator.

    Sometimes it can be like opening up a can of worms. I tried fixing a Trabant headlight or wiper switch but after taking it apart, I never could get it back together!

    One more thing. The wiper shaft system could be what's actually stuck. It may not even be the motor. Once you disconnect the motor that should be apparent which part of the system is stuck.
    Buckeye601 likes this.
  5. Buckeye601

    Buckeye601 Puttering Along

    "One more thing. The wiper shaft system could be what's actually stuck. It may not even be the motor. Once you disconnect the motor that should be apparent which part of the system is stuck."

    That is a very good point. I assume it is the motor, but maybe it is somewhere in the wiper arm system that needs to be freed up.

    I will take the motor out when I have a chance and see if I can get it to turn, or if the wiper arm assembly is frozen and go from there using your suggestions. It looks like it is relatively easy to pull that motor off (assuming that you can do so without needing to remove the dash - I have not looked up there yet to see), so might as well do it.
  6. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    I've never done a trabi wiper motor, but a many of Renault,Peugeot, and Lucas electric ones(some older lucas models look like this). Most often they are frozen by a wad of rock hard grease. Very rarely do they burn/ short out. When you take it apart, have a multi-meter on hand, and check for shorts. The brushes can get greasy, and lose contact too. Most often it is something simple.

    Shouldn't need to take the dash off. I wanna think it is 3 -4 bolts, and the pivot nut..
    Buckeye601 likes this.
  7. Buckeye601

    Buckeye601 Puttering Along

    I will definitely see if I can get it freed up before purchasing a different one. I see there are several available on ebay.de but the shipping costs are not very favorable, in most cases exceeding the cost of the item by a fair amount. From what I can see under the cover, it really does not look to be in terrible shape, with no apparent burn marks. It certainly would be better if I can fix my own.

    I just need time to pull it out to examine it, which is proving difficult given my full-time work schedule, my "need" to watch college football on Saturdays, and my dissertation proposal work. And I am very much itching to get this car on the road, but my guess is it will take most of the winter to get to that point.
    Last edited: Sep 30, 2019
  8. Buckeye601

    Buckeye601 Puttering Along

    I pulled the motor this afternoon. It appears the shaft is free - at least I can turn it with some pliers. It takes a bit of force but it does not seem overly difficult, and definitely is not stuck fast in place.

    I checked the switch with a test light and I am not sure what to make of it, and the schematics I have don’t really explain it, or perhaps I am a bit deficient in reading them.

    With the key in the on position and the switch turned to the left position, terminals 54d and 54 are hot, 31 and 31b no power. With the switch turned to the right most position (which I assume is on, but I guess I don’t know for certain) only terminal 54 is hot. I assume that all the wires are connected to the correct terminals on both the switch and the motor but perhaps something is not correct with that.

    Based on the schematic I have (which may or may not be correct for my particular car) terminal 31 appears to be earth, 54 seems to be power in from the fuse block, and I assume 54b would then be switched power and 31b would be neutral. If that’s the case, it seems the on position is when turned left which is the opposite of what I would have assumed. Does that sound like a correct conclusion? In neither position does the shaft turn even when not connected to the motor assembly.

    If so, what else should I look at to diagnose if the issue is with the switch, the motor, or something else perhaps? It seems to me the issue is with the motor and not the switch but I don’t know for sure. Any advice would be appreciated.

    Attached Files:

  9. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    By that diagram #31 is a ground. #31b is a switched ground. If you don't have a multi meter, jump #31, and #31b together with the switch on... Or to a good ground.

    Why not hook -6v to 31,31b+. And 6v+ to 54d, or 54? You will know right away..
  10. Buckeye601

    Buckeye601 Puttering Along

    I had my meter with me but turns out the battery was dead and I didn’t have time to run home to get a new one. So all I had available was the test light.

    I will try one or the other of your suggestions next time I have a little free time. Thanks for the help.
  11. turbofiat124

    turbofiat124 Premium Member Forum Donor

    How many positions does your wiper switch have? Reason being 6 volt wiper motors are one speed. So there should be just two positions on your switch (off and on).

    However you can use a 12 volt switch with the intermittent delay built into the switch.

    Someone installed a 12 volt switch with delay on my car. I didn't know it at the time as to why my wiper switch had an off, on and two delay positions.

    I *think* Trabant 12 volt have two speed wiper motors so when you connect a 12 volt switch with the delay circuitry to a one speed 6 volt motor, the switch acts kind of funky.

    The fast speed setting becomes a redundant delay mode. The two delay modes on my car seem to be the same frequency.

    I'm not sure why. My guess is because the 6 volt motor has just two brushes where the 12 volt has three brushes, the 6 volt motor lacks a wire so the system gets confused.

    I don't know if that makes any sense.
  12. Buckeye601

    Buckeye601 Puttering Along

    My switch is a plain two-position switch - on, and off.

    I have not had much time to look at it recently, but I believe that Spooky Ghost is correct that there is negative switching involved in this, which I was not considering last time I looked at it. I think that negative switching explains why there are two hot wires when the switch is in the off position (to the left) and just one when it is on. I think the power is routed through the motor and back on the second lead (54d). Once the switch is turned right to the "on" position, that wire connected to 54d is closed to ground, and thus does no longer is "hot" when tested with the test light or presumably a volt meter.

    I have not had time to think through what that means exactly for how each terminal is being used, but it seems as though the switch is operating properly as far as that one wire is concerned, and is not working "backwards" as seemed to be the case when I presumed that the switch was switching hot and not ground. My suspicion still is that there is an issue with the motor, and I noticed that Trabantwelt.de has a 6v motor listed there currently. Its design seems to be different, but it looks like the mounting points are similar or the same as the one I have, so perhaps they are interchangeable. Unfortunately, as with all their parts, there is only one picture of the part, so it is hard to tell if it is likely to be the same regarding the number of connections etc.
  13. phi

    phi Loyal Comrade

    I've just put a 6V wiper motor on our kitchen scales (old-school like your granny's). It shows ~1300g what means one of the cheaptest ways would be sending it as a 2kg mini-parcel to USA. The price for shipping is 16 EUR for postage and 4 EUR for track&trace/insurance up to 50 EUR.
    Before sending the motor, I would like to connect it with a switch to a battery and proof its working condition. And afterwards, you have to wait some days until I'm next time in Germany or see my German friend in Switzerland.
    How can you send money to Switzerland?
  14. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I see what your saying. The motor itself is grounded to the chassis through pin 31 but appears the switch is also grounded but for what reason? I could see if there was a delay function built into the switch but if your car still has the original 2 position (on/off) switch, then I can't understand why it would need to be grounded. What purpose does that serve?

    I could test the pins/wires on my wiper motor and tell you when there is power present to each wire but not the switch itself since somebody installed a 12 volt switch with the delay function on my car.

    Have you tried actually bench testing the motor just to rule out the switch itself? Just unplug the wires going to the motor (mark them before hand) then run a wire directly from the battery to each pin to see what happens.

    Apples to oranges: I was trying to figure out why the windshield washer pump did not work on my MGB. For starters when the car was de-smogged and converted to a Weber, there were two wires in the vicinity that went to the anti-dieseling valve. Somehow the correct wires got unplugged and the wires that went to the anti-dieseling valve got connected to the washer pump.

    But when looking at the wiring diagram, what I couldn't understand was why the pump is powered through the wiper switch, but is also grounded through it. So the motor is powered when the car is running but when the stalk is pulled back, it grounds the pump! Looks to me they could have simplified things by simply grounded the pump to the chassis and powering the pump when the stalk was pulled back.
  15. Buckeye601

    Buckeye601 Puttering Along

    I plan to pull the motor again and bench test it to see if the problem is in the switch or not.

    As far as the negative switching goes and the exact design they chose for that switch, I am not really familiar with automotive wiring. I worked for ten years in the engineering department of our local electric utility and understand AC power and wiring fairly well, but the peculiarities of vehicle wiring are not something I am yet comfortable with yet.

    I will post a different schematic I found which provides some internal motor details for the wiper. It does not clear things up for me, but may be helpful for someone else in understanding the motor, or perhaps other detail in the schematic that they are interested in as it seems to be a well-done drawing.

    Attached Files:

    Last edited: Oct 14, 2019

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