V70: Wiper fuse blowing when ignition switched on

[TDIvolvo]

Hi all, I am posting some information here hopefully to help others because I found really VERY little regarding this matter after scouring the internet for some time.

Vehicle is a 2000 V70 classic. Wipers had started to loose functions and it was put down to the stalk probably being worn however on Friday night they were switched off and several minutes later when turned on they didn't come on. No scooshers, horn etc. so fuse #34.

On Saturday I went out and checked the fuse and right enough it was blown. Stick in a new fuse and it immediately pops, ignition was on but the stalk was at 0. So I turned off the ignition and put in another, turned on the ignition and pop. OK we have something not right here. Decided to take the stalk off first (it was cold and this meant I could sit in the car) as it is arguably the start of the system, at least logically speaking, assuming the wiring is fine. Took it off complete and put in another fuse - pop.

Gave up on the stalk there deciding it was possibly motor related and the system didn't need to be on at the stalk because the motor would still have a live feed if it wasn't parked.

Last night I started disconnecting things to see what it could be. First up I pulled the relay. Which is the big red one which is up above the pedals, you must take the lower dash panel off with a single torx and then sort of gently pry and pull it off.

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With the relay out I put in a new fuse, it popped, which was quite telling actually because with no relay there really is not much chance of it being control circuitry. I then pulled the headlight wiper motor connections, which are the dark red connectors up above the headlight cluster, fuse still popped.

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So it was time to take the scuttle off. This is very easy, undo the nuts from the wipers and I was lucky that mine just pulled off with some wiggling. The blade pushes down onto the windscreen making the wiper arm sit at an angle to the boss, so it's best to hold the blade up and pull it straight off and it should come right off. Then undo about 4-6 torx screws at various points along the scuttle, on mine some were buried by leaves. Remove the two drain pipe clips and pull them off. Then just pull it towards the front of the car as you lift it at the front so it clears the wiper bosses.

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I disconnected the wiper motor and put in a fuse - all good. Excellent. Removed the wiper assembly (2 x 10mm bolts) and figured out the wiring and powered it up with a 12V supply, motor runs a treat. I then laid it on the engine and plugged it back in, turned on the ignition and the system automatically parked and the fuse stayed OK. Switched them on and within about 3 seconds the fuse popped.

At this point I removed the black section of the gear housing and cleaned up the contact plate, I found a spark eroded section of the track (18:00 position) that rough edge really doesn't look in good order - it's full of blackened grease, all that could make grease in here black would be carbon from arcing, so my thoughts are that the damaged section you can see has possibly worn so far through that it may be a dead short onto the gearbox casing, to be honest I didn't meter that out but I was getting dead short across all the terminals when the wipers are in the "parked" position - about 1 ohm resistance. Not good.

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I have decided this is the culprit and have ordered a second hand one off ebay. I will update this post tomorrow night assuming the part comes tomorrow.

Anyway, lots of photos to help people out here.

[TDIvolvo]

OK - new wiper assembly arrived here today, very pleased with the eBay based Volvo breaker.

I will fit it tonight and fingers crossed that's us as the MOT is tomorrow/Friday.

Anyway, look at this.

Old:

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New:

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Quite clearly the huge hole in the contact plate is not meant to be there, also note how clean the grease is - the grease in the old one is badly contaminated with carbon dust.

The unit itself looks as you would expect for a part from a 1998 car, but the contact pads and the plate looks as though it has had about a 1/3 of the use put on it as the one I removed.

[TDIvolvo]

Well that's it fixed.

Got it installed last night, I forgot to note which side the long arm goes on and which side the short arm goes on, quickly worked it out from the wipe pattern on the windscreen.

Hardest part of the whole exercise was replacing the scuttle.

In the end this was the best way to do it: Line it up on the passenger side first and slot it under the strip at the base of the windscreen and put in loosely two screws, the drivers side is more complicated because the fuse box sits quite high and stops the scuttle from just sliding in. Once you have it locked in place on the passenger side you can then pull from about 2/3 of the way over to the end section and pull it towards the front of the vehicle and get the top of the scuttle to slip under the strip. at this point it should all slot in but will sit jammed high on top of the fuse box, a swift bang with your hand should then shock it down the back. Sounds a bit brute force but it just needs a bit of a jolt to drop it down. Wiggle it all around until it sits bang on and do up the screws. I took the opportunity to give the whole scuttle and under the scuttle area a good clean and spray with silicone.

With the bonnet on full access mode (straight up) you can line the blades up easier.

I need a wiper stalk though as my position 1 needs convinced before it will work, 2 and int are fine.