760 Intermittent wiper Mod - may fit other 7/9xx

[Laird Scooby]

While trawling the forum in general one day, i came across this article :

https://www.volvoforums.org.uk/showthread.php?t=97299

After a fair bit of double-checking, cross-referencing etc, i found the intermittent wiper relay and associated wiring in my 760 was similar so i bought one of those VAG "Relay99" and swapped them over.

This is the result with the delay set to very short (about 2-3 seconds) at first then extended to about 20 seconds.

https://youtu.be/LIC5EiN45YI

Later in the video it also shows that you now get 3 wipes with the wash function instead of 4 but what isn't obvious is a half second delay from pulling the stalk to wash before the wipers start - reduces the risk of trying to wipe a dry screen!

It also shows the other little wiper system update, the S/V40 fan/mist washer jets that vastly improve the washing of the screen.

Operation is as described in the link but some extra information is VAG cars used this relay from 90-94 and 97-2004 and it's easiest found on fleabay by searching for either VAG 357 955 531 (part number) or for "VAG Relay 99" but make sure the part number is correct.

While i know it works in the 760, i am fairly sure it will work in the 740 and 9xx models as long as the pinout on your intermittent relay has the same pinout as this one :



The 760 has horizontal relays so uses a different part number to the 740 which will have a vertical relay, the 960 probably uses the same part number as the 760 so would suggest the 940 would use the same as the 740.
The important bit is the pinout and the wiring - the wiring diagrams appear the same for those models so as long as the pinout on the relay is the same, it should be a nice, cheap, easy mod.

[aardvarkash10]

ooooooo - cool!

*googlesearches for wreckers handy to home...*

[360beast]

Back when I drove a mk2 golf (Hey it was slammed with stretched tyres and yeah I'm disgusted too) it was common for people to fit the relay from the mk3 to make an intermittent wiper and it was only last week I randomly started thinking about doing it to the 940! Saves me the hassle of figuring it out, thanks Dave.

[griston64]

I like the sound of this too ! Especially as my intermittent function appears to be set to weekly

[tofufi]

Is this just plug and play? No wiring amendments?

Might be worth me doing

[Laird Scooby]

Originally Posted by griston64

I like the sound of this too ! Especially as my intermittent function appears to be set to weekly

That was why i pounced on the post describing the upgrade for the later models Mark. My Rover has variable intermittent that can be varied between 5-15s (with the default being 10s if a problem occurs with the CCU or fusebox) and i found i really missed the variable facility on the Volvo.
I'd looked into it previously by reverse engineering the original relay but due to a bout of ofrgetfulness, i'd worked it all out based on the rear wash/wipe relay!

Originally Posted by tofufi

Is this just plug and play? No wiring amendments?

Might be worth me doing

No wiring needs be touched Jim, literally a relay swap. Make sure you get the front intermittent/wash-wipe relay though or your tailgate wiper is likely to do some very strange things!

If, like me, you find the rear intermittent delay too quick at times (for example, driving on damp roads with spray coming up but not enough to need the usual 10s delay) or too slow like when it's raining but not hard enough to need constant wiper but more than the standard delay can handle, i can supply details based on my rear wash-wipe/intermittent relay to convert yours by adding 3 resistors and a 3 position switch.

[Rversteeg]

I have replaced the original interval relay for a programmable one. The interval time is programmed by switching the interval on and off so the wipers start to wipe. Then simply wait until the next "wipe" is required and switch the interval on permanently. It works so well that I seldom use any of the other continuous modes.
No rewiring required, just exchange the relay.
https://www.rendcarparts.com/volvo/p...80/RD3523610PA

[Laird Scooby]

Thanks for reminding me Rob, i meant to add this to the original post but forgot!

https://www.carbuilder.com/uk/progra...nt-wiper-relay

It's £12 +P&P (not sure if VAT is added) and is in the UK so less in shipping charges or should be.

I found it after i'd already ordered my VAG "Relay 99" from an ebay breaker/seller.

Handy to know it also works for the 240/260/740/760 and should also work in the 960 as i believe they use the same OE intermittent relay.

[Rversteeg]

The VAG relay does not seem to work on the 740 and 940 series. I understood from others that the I used is a straight fit for the 940, but for (some?) 740 one of the plastic pins needs to be cut off.
Anyway, once you are spoiled with a feature like this, you wonder how you ever managed without it, just like central locking with a key and cruise control!
Rob

[Laird Scooby]

Originally Posted by Rversteeg

The VAG relay does not seem to work on the 740 and 940 series. I understood from others that the I used is a straight fit for the 940, but for (some?) 740 one of the plastic pins needs to be cut off.
Anyway, once you are spoiled with a feature like this, you wonder how you ever managed without it, just like central locking with a key and cruise control!
Rob

Interesting Rob, when you say plastic pins, do you mean on the relay or the relay board?



No plastic pins on it, or at least the one i used. I wonder if the relays tried on the 740/940 you say it didn't work on were in fact the "99" designation? If they weren't, they are just the standard interval relay with no programmable feature.

That would explain it!

You're right about being spoiled though, that's why i wanted the feature on my 760 - can't understand why Volvo didn't do it as standard, after all most of their competitors were!
Likewise with cruise control, most top spec cars from the mid 80s had that as standard, the facelift 760 and later the facelift 740 would have been ideal points to introduce it as standard.