Rear window wiper relay seems to work but the motor doesn't :S

[Starlet_Sam's_Mum]

Hey guys,

My rear window wiper doesn't work at the moment. I've tried two different motors and relays and they all do the same thing. They basically click (so I assume the relays are getting power on the 5v rail), but when they switch the motor doesn't move (which I'm assuming connects to a 12v rail).

Does anyone know what could be causing this?

Thorpy suggested fuses maybe, but apparently the rear window wiper fuse is the same as my front wipers and they work fine.

Any other suggestions guys?

Cheers,

Perry

 

[weeJohn]

You should have 12 volts at the motor all the time on 1 wire if the fuse is ok, the washer motor is off the same fuse so its an easy way to check if the fuse is good. Its an odd setup, the relay puts 12 volts to the motor for the first half of the sweep then there is a switch in the motor that keeps that 12 volts on the motor through the permanent 12 volts until it returns to its original position. When you set the stalk switch to on then you should get 12 volts to one of the other wires on the motor plug if the relays and stalk switches are ok, but the motor needs to be well earthed to get it to start moving.

 

[Starlet_Sam's_Mum]

Thanks for the reply John, I've checked the earth next to the motor, its really clean so I thought that was okay and the water jet works fine.

when I switch the stalk the relay clicks, is it not energising the coil in the relay allowing it to pass 12v?

 

[glanza_kow]

Just for daftness mate, have you bench tested the motors your trying? I had similar(ish) problem with mine before. Turned out the spindle was seized thus burning out the motor when keep trying it. I would have guessed if you've got power up to the motor and you know the motor is good, it should work.

Have you got a test probe?

 

[Starlet_Sam's_Mum]

I have a multimeter, but I've left it at my Dads. I've tried 4 motors in total, one off my car, one I bought off someone on here and then I went to buy another one in Sheffield off Thorpy and neither of his worked and he knows one of them worked 100%. I'm confident the motors are fine.....Sort of.....maybe.

The voltage thing is clearly the best thing to do though! I need to probe my head off!

 

[Starlet_Sam's_Mum]

Ok guys, I got the multimeter out. So I get a constant 12V on one of the leads and when I switch the stalk they all go to 12V.

Is that correct? :s

Should my next step be to take the motor apart and just see if it will spin on its own?

 

[weeJohn]

Thats correct, you should loose the 12 volts at 1 of them when the motor starts turning, it will only have it on all 3 at the starting point. Take that earth wire off the bolt and measure the voltage at the lug of the earth wire when you switch it on. If it has 12 volts on it then you have a bad earth connection to the boot lid or body in general I would bet. Try a link from that wire to the battery terminal to be sure all the rest is ok.

 

[Starlet_Sam's_Mum]

Hey John I missed this reply, thanks I will give those a try.