Electric blinds..?

[g8dhe]

Geoff - is that really a problem as I was thinking non conductive oxide coatings was the main issue, and opportunities for substantial dirt to get in would be minimal? The idea if anything is to clean and flush out?

I've seen the problem occur with WD40 myself, not in a car but on open relay contacts, despite the fact that relay contacts are usually self cleaning - they can only clean so much! The problem arises when they layer of muck builds up and the small amount of wiping motion a relay contact has wasn't enough to clear it away. The same situation can occur with switches. I would agree that if you can keep dust and muck away from the area afterwards it should be ok, but normal electrical contact cleaner uses a much lighter oil and a lot less of it than WD40. Remember WD40 was designed to leave a substantial coating on the surface to prevent corrosion, it was never designed for use as a cleaner!

[mikeonb4c]

Took the offending front passenger blind switch out just now. (Killing a bit of time while my partners car has MOT!)
It does come apart there are two metal rockers in there & 4 contact points two at the top, two at the bottom.. The earth seems to be at two points in the middle, one on each rocker where it vee's in the cradle & pivots slightly.
These metal cradles can be removed by sliding em out the side of the board.. Pretty much everything in the switch contacts was dirty (a little like the mouse mung you used to get in the old computer ball mouse!) I cleaned the four contact points, and i also paid attention to cleaning the two metal cradles where the two contacts sit & pivot, plus the point where the contacts actually touch the cradle on the vee...
The switch seems more responsive.. & more to the point my passenger door blind lifting on opening pimp (should they be left down.) is now 100% reliable!!
Though i have cleaned the contacts on the negative switch on the sliding door that triggers the light & pimp just to be on the safe side...

V. useful to know that jaylee and thanks+++

Was the switch easy to extract from its dashboard mounting (how?)

[mikeonb4c]

Remember WD40 was designed to leave a substantial coating on the surface to prevent corrosion, it was never designed for use as a cleaner!

I was thinking of it v. much in those terms so that - rather as with vaseline on battery terminals, it both conducts and protects against oxidisation (dirt welcome but harmless due to conductive presence of WD4). But all that is based on my assumptions about what WD40 is.

Having read jaylee's post, maybe a quick strip down and clean up is best anyway if the contacts have gone and got oxide (or whatever) layer on them. Should set them up for the next 15yrs. Now, would the lightest smear of vaseline afterwards help or hinder things I wonder?

[g8dhe]

Vaseline doesn't conduct, on battery terminals you rely on the pressure of the bolt to squeeze the vaseline out of the contact area, what it does do as you say is prevent any further ingress of moisture, especially with acidic content from around the filling vents, once the bolt has been tightened then you should get an air-tight seal between the clamp and the lead terminal which is where the best electrical contact is made.

With switch and relay contacts, you don't get the same levels of pressure being applied as above and electrical contact is reliant on the small amount of rubbing that takes place the "self cleaning" action to provide the electrical contact. However the rubbing is a very small amount and whilst it is sufficient to dislodge/displace a layer of thin oil or small bits of carbon anything more solid won't be moved.
Many (many many) moons ago when I was an apprentice with The Post Office (before it became BT) up at the Bletchely training college , the tutors would put faults on relays by simply sliding a bit of the old brown wrapping paper between contacts, they didn't leave the paper in between the contacts, just the tiny little fibres from the rough surface would remain, you couldn't even see them with a magnifying glass, but they would remain between the contacts and just roll with the cleaning action, all the same that was sufficient to keep the surfaces isolated !

[jaylee]

Remember WD40 was designed to leave a substantial coating on the surface to prevent corrosion, it was never designed for use as a cleaner!

I was thinking of it v. much in those terms so that - rather as with vaseline on battery terminals, it both conducts and protects against oxidisation (dirt welcome but harmless due to conductive presence of WD4). But all that is based on my assumptions about what WD40 is.

Having read jaylee's post, maybe a quick strip down and clean up is best anyway if the contacts have gone and got oxide (or whatever) layer on them. Should set them up for the next 15yrs. Now, would the lightest smear of vaseline afterwards help or hinder things I wonder?

Mike, the only grease i saw was on the top side of the two pivot contacts where the black plastic mechanical rocking action of the switch swings two arms that adjusts the position of the two contacts in tandem, (which i left alone.) this acted as a lube as the plastic pushed against the metal... NO lube should be & need not be on the underside where it connects to the board with the pins that run out the back!
(I wish i took pictures now, But all will become apparent when the switch is took apart! )

The underside that makes the two electrical contacts (on 3 point each contact.) i just cleaned the mung caught up on the contacts & reassembled..

Thanks fer yer diagram posting again Geoff, it really helped me understand how important a part the front switches play in the blind loom..!

[mikeonb4c]

Vaseline doesn't conduct, on battery terminals you rely on the pressure of the bolt to squeeze the vaseline out of the contact area, what it does do as you say is prevent any further ingress of moisture, especially with acidic content from around the filling vents, once the bolt has been tightened then you should get an air-tight seal between the clamp and the lead terminal which is where the best electrical contact is made.

With switch and relay contacts, you don't get the same levels of pressure being applied as above and electrical contact is reliant on the small amount of rubbing that takes place the "self cleaning" action to provide the electrical contact. However the rubbing is a very small amount and whilst it is sufficient to dislodge/displace a layer of thin oil or small bits of carbon anything more solid won't be moved.
Many (many many) moons ago when I was an apprentice with The Post Office (before it became BT) up at the Bletchely training college , the tutors would put faults on relays by simply sliding a bit of the old brown wrapping paper between contacts, they didn't leave the paper in between the contacts, just the tiny little fibres from the rough surface would remain, you couldn't even see them with a magnifying glass, but they would remain between the contacts and just roll with the cleaning action, all the same that was sufficient to keep the surfaces isolated !

Thanks Geoff. You know, I often wondered about that (vaseline not conducting) but you're the first person I've managed to get a straight answer from when I ask. Still living and learning. Vaseline is off the menu then - but am I right in presuming WD40 conducts?

[g8dhe]

Nope WD40 doesn't conduct either! I can't think of any oil based liquid (other than carbon black) which does! Carbon Black is just carbon particles in an oil sludge!