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Discussion Starter · #1 ·
So, I bid on a used wiper motor on ebay, never expecting to win it at 99p, but I did. Its a Bosch, complete with E Class mercedes mounts etc (which could be handy). Anyway, it just has 3 wires coming from it, and all the examples I have seen have more than this. I have a brown and a red (presume live and neutral?) along with a much thinner whiteish wire. I have enclosed a pic, anyone offer any help? Thanks.
 

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I wish I could help. If there is no movement maybe it has a bad solenoid? Also wanted to be clear. The thread title says Wiper Motor but in your post you say Starter Motor. If it is a starter motor than 5amps is not going to be sufficient to get it going.

http://www.aa1car.com/library/2002/cm10220.htm

According to this an average starter draws 60 to 150 amps with no load.
 

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I'm not sure but I think the red is your positive and the brown is the low/high wire. The white I'm not sure about? It could be a ground? But I'm just guessing on the white wire.
 

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try ground to the body , connect positive to the red. Then touch the brown to the red and positive, if it works then jump the brown wire to the white one which might be the park. I dont know the wire diagram but just keep trying different combinations and 5 amps might not be enough to turn it and or enough for proper torque .
 

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Discussion Starter · #9 ·
Thanks for all your input. I have tried grounding the white wire to the body etc. and no joy. I did turn the motor by hand to make sure it was free and discovered that Mercedes must have some funky set up for this wiper set. The crank arm is blocked by a couple of raised sections on the wiper connectors, so only has 180degrees of movement. So, I guess that Merc must have hade some kind of controller, possibly reversing the polarity so the motor went back and forth, rather than spinning all the say round. Unless someone has rebuilt the whole motion system incorrectly, but the is no obvious sign of this. Does this sound likely to anyone? Would seem a step away from the norm, even with rear wiper motor systems, and this one is definately a front (even says so on it, and has fixings for 2 arms) so it is looking like it may be a dud. Oh well, only £1.
 

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Discussion Starter · #11 ·
Maybe, I might try more in depth google search too.

I am also thinking of stripping the motor off the mechanism, cleaning the contacts etc and then hooling it to a car battery to see if it just needs more ampage to fire.
 

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Discussion Starter · #13 ·
I will. However, I am trying to understand how/why that might work. Surely running power through the 2 large cables is what Mercedes do to power the motor, so why doesnt that work? I am not amazingly electrically minded so dont be too harsh!
 

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i just bought two motors wiper motors from the auto wreckers , had me stumped for a bit and the ground is the body. When the wiper motor is attached to the car it gets grounded threw the body of car. The body of the wiper motor just acts like a ground wire. You shouldnt really hurt anything trying, I have made lots of sparks and had many computer power supplies shut down testing wiper motors. In the end they still all work fine. The only caution is the wall adaptor will not have an internal shut off if it gets overloaded and may burn out.
 

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I will. However, I am trying to understand how/why that might work. Surely running power through the 2 large cables is what Mercedes do to power the motor, so why doesnt that work? I am not amazingly electrically minded so dont be too harsh!
The red and brown could both be positive voltage, one high speed and one low speed. If that's the case then connecting negative voltage to the metal body would complete the circuit. The white wire is much smaller gauge which suggests that it is most likely the park wire. The park wire may need to be connected to negative voltage to get the motor running.
 

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Discussion Starter · #16 ·
Thanks J man, that helps me understand why you are asking me to do this. Alas I have tried and still nothing.
I decided to pop the cover off what I was expecting to be the gear box section of the assembly, and whilst unable to remove it completly, I could see inside that it has a PCB complete with what looks like a capacitor of some kind. Is this normal? Could this be the reason for it not working? I am starting to think that I may be flogging a dead horse.
 

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Discussion Starter · #18 ·
I have been able to remove the case and wire straight into the 2 wires to the motor. The motor works, though because it does not have whatever funky controller working, it just hits the bracket, so need to remove it from the bracket and decide on a prop to build to make it operate!
 
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