Technical Testing front wiper motor

[Dodgy Geezer]

Ho-hum...my wipers don't work.

The manual, surprisingly, shows NO FUSES for these on a Grande Punto. It says there is an 'overload protection' feature which resets after time - so I'm guessing that electricity is going to the wiper motor unit and there is a problem with the unit. I assume the 'overload protection' is in the wiper motor unit. I'm going to have a go at mending it before buying another unit...

To help me diagnose this, does anyone know what the pins on the front wiper motor do?

 

[digger58]

Whats make you think power is going to the motor? Do you have a multi meter?

 

[Dodgy Geezer]

I haven't actually got the wiper motor out yet - I'm waiting for a wiper arm puller. But because there appears to be no fuse for the front wiper motor, the only way I can find out if power is going to it is to take it out and test the input cable.

If there is no power in the input cable I assume that I have to trace it and install another cable, or disassemble the windscreen wiper stalk.

There MUST be a relay for the motor somewhere, which could also have failed - but the manual gives no hint of where that might be...

 

[digger58]

Don't guess, get a multi meter and make sure about live feed to the motor before taking it out.

 

[Dodgy Geezer]

I have a multi-meter. How do you suggest that I check power going to the wiper motor without taking it out? I don't think you can get to the motor connector without taking it out, and there appears to be no fuse...

 

[digger58]

You may be able to get at the motor connector without taking the motor off, have a look. I've never had to take my wipers off the GP. A slight bit of leverage on the underneath of the wiper arm and a sharp tap on the spindle (leave the nut on so you don't damage the thread) should shock it loose.

 

[Dodgy Geezer]

I'm going to use a puller - it seems easier. Only then will I be able to see what the wiper system looks like.

Taking the complete wiper system out should only be a couple of bolts at that point. But I must admit that I expect fault finding to be difficult.

In the old days, if a switch was turned, electricity went to an item. Nowadays, if a switch is turned, I expect a computer to decide to supply electricity or not, so the problem might be a software one!

At the same time as my wipers went, I got the ESC light and the hill start warning. I bought a laptop connector and loaded Multiecuscan, which told me that I would have to buy the full version if I wanted to talk to my car - I think it will be easier to get a garage to reset it...

 

[Dodgy Geezer]

Wiper update:

I got the puller (a day late!) and off came the wiper arm, easily.

The scuttle cover comes off easily as well, though with concealed push-studs, and then the wiper unit is only held on with two screws,

I took off the connector, and checked the pins on the cable. These gave voltages between 10 - 12v, depending on the pin and what was switched on in the car. So it looked as if the problem was in the wiper unit.

I opened up the wiper unit gearbox, but couldn't see any obvious problem. I tried to take the motor casing off, but the brush unit seems to catch in the casing, so I could only get it open by a small gap. What I could see looked OK to me.

So I put everything back together, and plugged the wiper unit back on. Now, it worked perfectly.

There are several connectors both on and inside the wiper unit which I had to disturb to disassemble it. I suspect that one of these was not making good contact, and the disturbance has corrected it.

I wonder how many people have forked out £250 for a wiper unit replacement when the only problem might have been a poor connection...?

 

[Dodgy Geezer]

Damn this plastic world....

Since there was no wood available, I couldn't touch it. Anyway, to continue my story, I put the scuttle cover back, and attached the wiper arms today. Then I started the wiper. It didn't work.

I took it back out again, and disassembled the whole thing - including the motor casing. Everything seemed to work perfectly. I put it back on again, and it worked this time, and, so far, has continued to work.

I could treat the wiper unit as suspect and get a new one, but I have a sneaky feeling that the wiper unit worked perfectly all the time. I think that the problem is in the control board for the wiper unit, which must contain the relay, the rain sensor electronics and the overload protection. It could be the overload protection cutting in incorrectly?

Anyway - this leaves me a bit stuck. I have no confidence that a new wiper unit will sort the problem, and can't find out where the wiper fuse/control box is...

 

[varesecrazy]

Damn this plastic world....

Since there was no wood available, I couldn't touch it. Anyway, to continue my story, I put the scuttle cover back, and attached the wiper arms today. Then I started the wiper. It didn't work.

I took it back out again, and disassembled the whole thing - including the motor casing. Everything seemed to work perfectly. I put it back on again, and it worked this time, and, so far, has continued to work.


Anyway - this leaves me a bit stuck. I have no confidence that a new wiper unit will sort the problem, and can't find out where the wiper fuse/control box is...

https://www.fiatforum.com/grande-punto/221048-windscreen-wiper-fuse.html

 

[Dodgy Geezer]

Thanks for the reference.

That simply tells me that the fuse isn't behind the glovebox, and no one knows where it is. Or even if it exists, because it isn't mentioned in the manual fuse list. Which doesn't help much...