Polo From Wipers Not Working - Odd One

**bigjohnuk** · 09-11-2014,06:34 PM

Hi

Got an odd one. when I start up the Polo in the morning, the wipers do not work right away. I have to wait a few minutes and when on Fast setting the wipers will then work in all settings. They generally are OK for most of the day.

Any ideas why this happens please.

OK 2002 Polo 52 plate 1.4

John

**Flash2** · 09-11-2014,09:45 PM

Hi John, welcome to the forum.

When you say the wipers don't work right, can you explain what are they doing?

Jim.

**bigjohnuk** · 09-11-2014,10:10 PM

Hi Jim,

When I start the car and I need to clear the screen. I put the wiper lever up and nothing happens, I move it to the slow setting and still nothing happens, I move it to the fast setting and still nothing happens. Then I move the level back down and try again. After a few minutes when I have moved the wiper lever up to fast, the wipers start in fast mode. I then move the level back down to slow and the wipers slow down as normal. I then drive to work, then later when I go home the wipers work as normal. It is not until the next morning that the wipers do not work again.

Any ideas ?

John

**Doctle Odd** · 09-11-2014,10:15 PM

probably the relay is on its way out

**bigjohnuk** · 09-11-2014,10:20 PM

Hi What type pf relay? Can you advise part number of Polo 1.4 late 2002 plate 52

John

**Flash2** · 09-11-2014,11:07 PM

John, the wiper relays on your car are built into the power supply control unit and can't be replaced. It could be the relays that are faulty but you'd want to be sure before replacing an expensive ECU. Can you hear the relays operating when you switch the wipers on? Even if you hear the relays operating, that doesn't mean they aren't faulty. Youd have to do a few checks with a voltmeter to check what's coming out of the ECU.

Jim.

**bigjohnuk** · 09-11-2014,11:33 PM

Hi

Power Supply unit. Is this the one on top of the Battery ?

POLO MK4 9N 2002-2005 ONBOARD SUPPLY CONTROL UNIT 6Q1937049D

John

**Flash2** · 10-11-2014,01:08 AM

No, it's behind the dash on the driver's side.

**bigjohnuk** · 11-11-2014,04:23 PM

One thought I had also..... could it be the battery that may not be strong enough ? Just odd that it does not start until a few mins after starting the engine.

**Flash2** · 11-11-2014,08:41 PM

Originally Posted by bigjohnuk

One thought I had also..... could it be the battery that may not be strong enough ? Just odd that it does not start until a few mins after starting the engine.

I doubt that John. If the battery was so bad that it couldn't power a wiper motor there is no way it be able to power the started motor. And once the engine has started the electrics are all supplied power from the alternator.

The way it's working does sound a little strange as if something in the electronics of the supply ECU is charging up or something. It might be worth trying the old disconnect the battery trick (terminal 30 reset if you want to sound technical). Disconnect the neg battery terminal and touch the disconnected neg lead onto the positive battery terminal. That will discharge everything. It's easy and doesn't cost anything, so worth a try. And it's surprising how often it actually does fix things.

Jim.