Problem with Corsa C imtemittent wiper

Won't be the first time you have been wrong though, will it?

;-)

Chris

Conor, I'd put the spade down before that hole gets any deeper.

Wiring diagram can be found at

First tests I do are at the wiper motor connector (easiest bit to get to) with it disconnected.

Check for the following on the vehicle wiring side (The terminal letters are marked on the connector) Terminal A should have 12V with wiper switch on speed 1. Terminal E should have 12V with wiper switch on speed 2. Terminal B should have continuity to earth. (those 3 are obviously working if the wipers move, so you can ignore them) Termainl D should have a permanent 12V feed with the ignition on.

Now with the ignition switch and wiper switches off, you should have continuity between Terminals C and A, which I'm guessing is where the problem lies. The wiring between these two terminals, passes through the two wiper motor relays, and a fault with the NC (normally closed) contacts in either relay will cause the park system to fail.

Unfortunetly, the relays are located in the Body Control Module housing. That's the big plastic box at the N/S (passenger side) of the scuttle panel. You'll want an appropriately sized torx screwdriver (25 I think, or possibly

20) to unscrew the cover. You do not want to damage the box/seal, otherwise you risk filling the BCM with water and getting a nice water sloshing sound, aswell as water leaking into the vehicle. The two relays are in the front group of relays, and are the two in the centre row (if you take the row as as running front/back) with K69A being at the front behind the big yellow flasher unit, and K69B the next one back.

And now the bit just for Conor (you'll need to study the wiring diagram for this bit). With the wipers on, power is applied direct to the wiper motor terminals A or E dependant on speed. When the wipers are turned off, power is provided through terminal D, which passes through the park switch, then back through the NC contacts in both relays before powering the motor through terminal A. When the park position is reached and the switch is activated, it moves the contact from Termainl D (+12v ignition supply) to Termanl B (earth), which in effect shorts Terminal A to ground, braking the now freewheeling motor. If you were to disconnect terminal C, under certain conditions the wiper motor could quite easily freewheel past the park position and keep going.

Absolutely brilliant information moray. Now all I need is a day when it's not constantly raining (LOL).

Thanks again.

Is this the same location for a Combo Van 53plate 1.6 Petrol?

Just id rather ask before taking it to bits...

Any ideas on the cost of the relays?

Tom

Should be identical. Combo C is identical to the Corsa C upto the dash level on the B-Pillar. Only difference in that area is the suspension specs.

Relays should only be a few pound from a motor factors. I'm pretty sure the wipers use standard size relays, but there's two common pin layouts, so check the diagram on the side of the relay/pin numbers to make sure when buying them. Failing that, just goto vauxhall that way you should get the right ones if you want to buy them before you strip the scuttle off.

Thanks, still not had chance to have a look, too busy messing with suspension (see other post) and it's been too wet to mess about on the street. One think I have noticed is when the wipers are in operation there is [1] some interference on the radio, which increases should the wipers stop in any position other than the proper park position.

[1] possible only on the down swipe - but I haven't listened too hard/paid much attention.

Thanks so far anyway

Tom

Possibly another symptom of a poor earth. If the motor is mounted on rubber bushes then an earth connection is needed otherwise it will be trying to earth through the spindles.

If it was a bad earth, the wipers wouldn't work on any speed.

Depends how "bad". A bad earth in a light cluster can make a rear light dim! A wiper earthing through the spindles would be a noisy bad earth. Think back to the old days when we had to emery polish the earth contact area of car radio aerials when we fitted them! No earth would prevent them from working - a bad earth would cause interference and poor performance.

I'll rephrase that. If it was a bad earth, the wiper fault would be consistent on any speed.

The fact that the wipers work on intermittent, and speeds 1&2, would indicate that the earth is doing a good enough job. The motor/switch/BCM doesn't change the motor earth just because you've moved the switch from on to off.

I was using the radio interference as an indication of a likely poor connection.

Hopefully in the relay the controls them?

It seems to be the park aspect that is the problem, as it just stops all over the place on intermittent, and when the stalk is returned to off from slow or fast wipe the wipers will park wherever they feel like it....

Tom