Another Windscreen Wiper problem.

[Ian21401]

Problem: Not every time but becoming more frequent.
Switch on wipers to slow speed and nothing happens. Move switch to fast speed and wipers operate normally. Move switch back to slow speed and wipers continue to operate until switched off. They “park” correctly.
Switch on to slow speed and wipers sometimes operate and sometimes not.
Switch wash/wipe on and washers operate every time but wipers sometimes do not operate.
Intermittent not operating.
I removed the column switch and opened it up. No obvious fault seen. Cleaned up the internal contacts, reassembled and re installed. — No change.
Removed scuttle panel and disconnected wiper motor multiplug. Separate earth lead left attached to it’s earth connection.
Connected jump lead from battery +ve to brown wire pin of multiplug — wiper motor operated immediately at slow speed. Connect jump lead to green wire pin in multiplug — wiper motor operated immediately at fast speed.
Reconnect multiplug and try using column switch — same problem as described at beginning.
Have now removed complete wiper assembly onto workbench but not sure of next step.
Comments courtesy of “brickboard” indicate that there may be a problem with the motor brushes but is it possible to access those brushes and how?
A presentation on YouTube indicates that there is a micro-processer within the motor and how to check the switch wiring resistances but I doubt if my 940 is as sophisticated as that.
Observations and suggestions please.
PS. The motor is an “Electrolux” marked: Volvo. 3518130. 500. W205 Sweden.

[Laird Scooby]

Refit the motor using it's original plug Ian, now use a piece of wire to jump the wiper switch connections to get the motor to run (simulating the switch) - if it runs every time the fault lies within the column switch. You could try squirting contact cleaner into it but it's not easy. There are a few on fleabay at the moment - might be worth a look.

[Ian21401]

Thanks Dave.
I didn’t hint at what my suspicions were as I didn’t want to influence any possible replies.
The fact that the motor appears to run as it should when disconnected from the harness and jumped from the battery seems to indicate that the motor is ok and the fault is elsewhere, ie, the switch. I managed to remove the switch and open it up before I did anything else. It was possible to gently prise the plastic switch casing apart to expose the contacts. They were a little dirty so I gently cleaned them up and sprayed them with contact cleaner. Three of the fixed contacts which have other contacts sliding on them do appear to be rather worn, which is not surprising after 27 years of use. A comment on “brickboard” suggests applying solder to fill the worn areas then smooth it down but I don’t think that I have sufficient expertise to do that. I’d probably melt the plastic bits.
I’ll double check the motor action whilst I have it on the bench then do as you suggest and check again.
I’m awaiting delivery of some butyl sealing strip to re-seal the air intake cover and secure the metal mesh before refitting the scuttle panel so I’ll trawl around for a replacement switch which will have to be for an estate as needs to have the rear wash/wipe wiring.

[Laird Scooby]

You'd done virtually all the diagnosis Ian, i only had to work out the logical conclusion. If the motor runs direct from a slave battery then the fault must be in the wiring or the switch. Next logical step is to jump the switch, if the motor works then it has to be the switch.

Had a look on fleabay, all of the UK switches for estates have disappeared leaving only saloon switches. While it would get you out of trouble for now, it's not a long term solution. I've been cosidering renewing mine as the "flick" function has never worked, the wipers work in the three normal (int., slow and fast) but no "flick" function. I've lived with it for 3+ years and was the reason i tried some contact cleaner in mine but i think i'll need a new one soon.

Have a word with Mark (griston64) as he's breaking a 98 940 at the moment, also Luke (360beast) has a 97 breaker but i can't think what year yours is at the moment so if those years are wrong then let me know and i'll keep looking.

[Ian21401]

Thanks Dave. Agreed about eBay. I’ve already got the headlamps from Mark’s donor car so I’ve contacted him and he’s going to try and remove said switch at the weekend. He’s fairly sure it’s the same switch as mine. Hope so.

[Ian21401]

Tested motor and linkage whilst on bench. No fault found. Lubricated everything including that cable prior to re-installing in car. I needed to re-seal the air intake cover but main dealer stated that the Volvo butyl sticky stuff was NLA but I think that I may have been fobbed off. I sourced and ordered some butyl tape on eBay but it’s not as sticky as the Volvo stuff although I think that it will do the job. Installed motor and linkage and tested it - OK. Refitted scuttle panel, difficult single handed, but got there. Light fading and rain starting so didn’t secure it and stopped for the night. Realised overnight that I had forgotten to refasten the cable tie on the motor wiring harness so next day removed scuttle panel again to do that then replaced and secured the scuttle panel. Tested motor etc. again - OK. Refitted NS wiper and tested with it lifted off screen - OK. Refitted OS wiper and tested with it lifted off screen - damn, something squeaking near the motor. Removed OS arm - no squeak. Replace it - squeak returned. Not of mind to remove the scuttle panel again so removed both wiper arms and the rubber spindle escutcheons and sprayed liberal amounts of “three in one.” PTFE lubricant onto linkage and anything else in the plenum chamber through the wiper boss holes and through the air grille mesh, with wiper linkage running. Squeak eventually faded then ceased. Everything now refitted and awaiting replacement wiper switch but car is useable again until then, unless the switch fails completely.