Help! IAC causing no start in ‘93 940

[Laird Scooby]

Originally Posted by Ian21401

Well spotted Dave. My, your eyes are good.

Not really Ian - opening the thumbnail in another tab (Move the curso onto the thumbnail then either centre click if your mouse has a clickable cente wheel or right click then "Open link in New Tab") then zooming to 300% really helps though!

Even then it's only just possible to see the L/H headlamp wiper is at an angle where it would be below the stop so i could still be wrong.

[Ian21401]

Originally Posted by Laird Scooby

Not really Ian - opening the thumbnail in another tab (Move the curso onto the thumbnail then either centre click if your mouse has a clickable cente wheel or right click then "Open link in New Tab") then zooming to 300% really helps though!

Even then it's only just possible to see the L/H headlamp wiper is at an angle where it would be below the stop so i could still be wrong.

Thanks Dave, more new info. I’ll give it a try later. It’ll be easier on my laptop.

[swedishsledmafia]

Ian is right, you do have good eyes Dave. And yes, it was indeed below the stop! I only tested the wipers after I took the photo, once I moved the wiper above the stop. Funny thing is, that’s the wiper that is working. The right one doesn’t, I’m assuming it is a motor issue as Ian mentioned, so I will likely get to that when I have the time. Not necessary by any means but nice to have a full pair haha.

Otherwise, I’m happy to see how much info there is online in general about DIY working on the 850! It’s not quite as user friendly as the 940 but there’s still plenty to do, 90s cars are where it’s at.

[Laird Scooby]

Originally Posted by swedishsledmafia

Ian is right, you do have good eyes Dave. And yes, it was indeed below the stop! I only tested the wipers after I took the photo, once I moved the wiper above the stop. Funny thing is, that’s the wiper that is working. The right one doesn’t, I’m assuming it is a motor issue as Ian mentioned, so I will likely get to that when I have the time. Not necessary by any means but nice to have a full pair haha.

Otherwise, I’m happy to see how much info there is online in general about DIY working on the 850! It’s not quite as user friendly as the 940 but there’s still plenty to do, 90s cars are where it’s at.

Thanks! In that case i'd guess they moved the L/H wiper under the stop to prevent it moving, quite a common thing if the other one stops working.
Could be down to corrosion in the connector plug or maybe there is a motor problem, no knowing until you pull it apart.
The real purpose of the stops is to prevent the headlamp wipers operating in heavy snow so the motors don't burn out. Once the headlamps are warm and melting the snow, they can be released from the stops so they work again.

Not sure i subscribe to the theory Volvo used to fit the stops but that's what it is.

[Rversteeg]

I thought the stops were there to reposition the wiper on the wiper arm every time it has finished half a stroke. I am not sure if the electric power to the wiper motor is cut when you put the wiper undeneath the stop. As far as I know the principle is the same as for a windscreen wiper. You only command the first part of the stroke and the rest of the stroke is completed via a fixed power feed. If the wiper is behind the stop, it would still be powered as long as you push the screen wash button. Too short to burn out probably.

BTW here you can find a repair instruction for a Saab wiper motor, identical to Volvo:
https://www.saab9000.com/procedures/...wiperepair.php

Rob

[Laird Scooby]

Originally Posted by Rversteeg

I thought the stops were there to reposition the wiper on the wiper arm every time it has finished half a stroke. I am not sure if the electric power to the wiper motor is cut when you put the wiper undeneath the stop. As far as I know the principle is the same as for a windscreen wiper. You only command the first part of the stroke and the rest of the stroke is completed via a fixed power feed. If the wiper is behind the stop, it would still be powered as long as you push the screen wash button. Too short to burn out probably.

BTW here you can find a repair instruction for a Saab wiper motor, identical to Volvo:
https://www.saab9000.com/procedures/...wiperepair.php

Rob

You've just described the self-park system Rob, there is a limit switch inside the motor to cut the power when the blades return to the rest position. The intermittent wipe function uses this so that all it needs to do is send a short (typically 0.5s) pulse to the main wiper motor terminal to intitiate motor action. The park switch is then closed connecting power from a switched ignition feed to the motor. When the motor once more reaches the rest position, the park (limit) switch then opens disconnecting the ignition feed to the motor and stopping it.

I can't find where i read about the function of the stops to prevent the wipers moving when the blades are either frozen to the glass or there is heavy snow which would burn the motor out, it may have been in my previous 740 handbook.
However there is a thermal cut-out built in to prevent the motor burning out if it can't move the wipers. Usually with heavy snow it can still move so the current draw isn't enough to trigger the thermal cut-out but still enough to shorten the life of the motor. By moving the wipers under the stops, it prevents them moving so the thermal cut-out operates more or less instantly, protecting the motor.

[swedishsledmafia]

That’s interesting that’s what the headlight wiper stops are for, Volvo really overthinks everything when it comes to little features like that hey. In general headlight wipers are so obscure but at the same time just plain nifty.

Speaking of wipers, I don’t know if I mentioned but my 850 has an apparently common issue on these cars where the wiper arm bends over time and this makes the blade ‘hop’ over the windshield while wiping, thus not actually making contact with it. It’s pretty annoying and definitely a visibility issue, so I’m going to try this fix:https://www.matthewsvolvosite.com/fo...hp?f=1&t=34250 and hopefully it works so I don’t have to buy new arms.

[Laird Scooby]

Originally Posted by swedishsledmafia

That’s interesting that’s what the headlight wiper stops are for, Volvo really overthinks everything when it comes to little features like that hey. In general headlight wipers are so obscure but at the same time just plain nifty.

Speaking of wipers, I don’t know if I mentioned but my 850 has an apparently common issue on these cars where the wiper arm bends over time and this makes the blade ‘hop’ over the windshield while wiping, thus not actually making contact with it. It’s pretty annoying and definitely a visibility issue, so I’m going to try this fix:https://www.matthewsvolvosite.com/fo...hp?f=1&t=34250 and hopefully it works so I don’t have to buy new arms.

You're right on that, i have two theories about Volvo :

First, take a simple, clever idea and over-engineer the living daylights out of it.

Second, take a bad idea, over-enginer it then complicate the living daylights out of it.

The wiper fix sounds interesting but i think it firmly fits into the second idea above. A much simpler idea that does work as i've done it on my 760 is to lift the wiper arm off the screen, remove the blade and with the arm still away from the screen, grab the base of the wiper arm at arms length. With the other hand, grab the end of the wiper arm. Using your shoulders, push the end of the arm towards the screen while keeping the base of the arm where it is.
This bends the end of the arm in closer to the screen without the need to mutilate the spring area. Don't forget that by doing the mutilation you're actually giving the spring more room and hence removing tension from it. Using my method increases the tension on it and is quicker, needing only the removal and refitting of the wiper blade from the arm and a few seconds of shifting your shoulders.

If you find afterwards the wiper blade judders over the screen, take an adjustable spanner and adjust it so it just slides over the wiper arm.
Have the movable jaw furthest from the screen, fixed jaw closest to the screen. If the wiper judders on the way up, have the open end of the jaws facing up the screen, if it judders on the way down, have the open end of the jaws facing down.
Now lift the handle of the adjustable spanner so the arm is twisted slightly.

Test and either repeat or correct as necessary.

A nice upgrade to the wash/wipe system is the mist/fan spray jets from an S/V40. This is them on my 760 :

https://youtu.be/LIC5EiN45YI?t=68

They're a straight swap, use an 11mm or 7/16" box spanner or deep 6-sided socket from the inside of the bonnet, slid over the rubber wiper hose after disconnecting it and push upwards. This presses the retaining tangs inwards allowing the old jet to pop up and out of the bonnet. Remove the old jet, swap the short length of rubber hose onto the new jet and (after cleaning the bonnet where the old jet has been) fit the new jet, reconnecting the washer tubing.

You can get aftermarket jets on ebay relatively cheaply, about £4-5 against about £18 from Volvo, i know you're in Canada and not sure about the ebay situation there but sure you can find them.

https://www.ebay.ca/itm/2PCS-Front-W...0/312179077401

Managed to find some for you! Also worth changing now rather than later when it fails :

https://www.ebay.ca/itm/NEW-VOLVO-WA...4/183077447311

Those upgrades should keep you busy for 10 minutes and give you hours of pleasure using them afterwards! The washer jets can also be fitted to your other Volvo too.

[Ian21401]

I can confirm that Dave’s method of bending the wiper arm and/or twisting it does work. I haven’t needed to do either on my current 940 but have successfully done both in the past on previous cars.

[swedishsledmafia]

Damn I do wish I’d seen your reply yesterday. It’s too late, the butchering of the wipers has already happened. That sounds like a way better fix, next time I guess.

I’ve heard of people putting S70 arms onto 850s, but not of swapping over the washer system! From what I can see in the video it looks like it works great. Thanks for the link, I’ll most likely buy them they’re very cheap. Just another one of those things to make your Volvo feel like home 😂 you can live in a car but you can’t drive a house.