Cleaning electrical switch.

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This is about about my car heater fan. It's not really about home or electronics repair, but I think you will be able to help me, and I'd appreciate it.
Can I regrease my electric switch? And if so, what should I use to remove the old grease? And more importantly, what sort of grease should I then use to regrease this 12 volt switch?
I have white grease, lithium grease, ball joint etc. grease (in a grease gun), some wheel bearing grease, "bicycle" grease in a tube by Schwinn, and maybe one more kind. I even have Crisco. :) Or I can buy something new.
My '95 Chrysler heater/AC fan speed switch no longer works in position 2, the one I use most often. A new replacement is very expensive**. I'm told the other speeds will fail soon.
With the switch dissassembled, it looks fine. There is some old grease on the contacts, now darker than new, but was brown and shiny when new. It is now, at least on the surfaces of the grease, a little bit harder than new, but when I push aside the grease with a wooden match stick stem, the copper contact underneath shows no burning or anything unusual. It's not as shiny as new, but I didn't think that would matter, since I'm sure the other three speeds aren't either.
I thought just mixing up the grease would be enough, and sure enough, the meter had shown infinity but now showed almost zero resistance, well under an ohm.. After reassembly it still tested good (with the low current used by meters) but after reinstallation, again the second position of the switch didn't work, not enough to power the fan (though the separate resistor that is used to lower the voltage to get a lower than max fan speed.)
**The switch is not sold separately and a whole new control panel costs 150 or 250 dollars. If I buy from a junkyard, I'm told it will probably already not work for the same reason mine doesn't.
What should I do?
Thanks for any help.
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I'm no expert but I'd remove all the grease from the copper contacts, (use alcohol, kerosene, gasoline, paint thinner, whatever, electrical contact cleaner in a spray can but not WD40, even soap and water). Grease (white) should go on the mechanical detents but not on the copper contacts; they should remain dry.
Perhaps you can somehow bend the wiper a bit so it makes firmer contact with all the positions (and the second in particular.)
meirman wrote:

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Bennett Price wrote:

Grease is commonly used in high amp switches to reduce contact burning/arcing. Removal of the grease will lead to a short life.
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In alt.home.repair on Sat, 21 May 2005 22:21:14 GMT Bennett Price

The thing is, it was made with lots of grease, a half a sewing thimble-full or more spread out over the contacts.
What is all that grease there for? Don't I need it? -- I see that George answered this. I think my tube of Schwinn grease was made maybe 40 years ago. No silicone. But I don't mind getting some silicone grease now. Better than spending 150 dollars.
Both my friend, who works on cars a lot, and the Chrysler parts guy said that a junkyard switch would likely be a problem. Unless I can find one from a low mileage car. Maybe.
One might think the Chrysler parts guy wanted to make a sale, but I was pretty clear when I heard the price that I wasn't buying yet. And still he didn't mind getting me the control panel, which I wanted to see since there were two prices and I wanted to be sure which price my style was, or putting the panel back in stock. He said a few years ago they sold 50 of these a week, and that they started with one speed bad but ended with all the speeds not working. He may have been exaggerating about 50 a week, but je was very nice and I don't think he was lying about anything including the junkyard ones.

I'll look at that.
Tomorrow I will test the switch with a load instead of a meter.

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It's not that hard to find low-mileage wrecks in junkyards.
-- Regards, Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?
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meirman wrote:

That is the answer to your question. It is not the switch that is bad, it is a resistor that is gone. They tend to fail one at a time.
On some cars the resistors are built into the switch and in others there is a separate resistor pack. You need to replace what ever has the resistors in it. I don't recommend trying to replace the resistor, just buy the pack or switch.
Note: Often this happens when the blower fan motor is starting to wear out. If it were mine and unless it is easy to get to that resistor pack, I would replace the motor and the resistor pack. If you can get to the resistor pack easily, and you can on some cars, I might try just that, but I suspect you will find it going out again in a matter of months.

--
Joseph Meehan

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In alt.home.repair on Sat, 21 May 2005 22:37:09 GMT "Joseph Meehan"

Thanks for replying.

Thats what I thought at first, but
a) The switch tested bad in the second position only.
b) A friend gave me a control panel from a Chrysler Caravan truck that he was scrapping**. The second fan speed, all the fan speeds work fine with his control panel. (I can't just take the fan speed switch from it because it won't fit in my heater control panel. And I can't use his control panel because almost all the connections are different in his control panel. The vacuum hoses are longer, not a problem; the electrical connection might be in the same place; but the hot/cold door control cable connects at the left rear corner instead of right rear, and is meant to come in at a 90 degree different angle. I tried to find some slack in the cable, but there isn't. (It's very hard, almost too short, even to connect the cable to the control panel it was designed for.)
The speed is controlled by the resistors, but if the switch is bad, then no current will reach the intended place on the resistor pack.
**Same year and same appearance on the front of the control (except my dim white letters and lines were bright white on his.) but behind the face plate, a different style of control panel. Everything rearranged.

Actually, the resistor pack is rather hard to get to, but the bigger trouble was that I loosened the screws for a long time, but neither came out. Couldn't see the other side. But like I say, it works with my friend's switch.

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meirman wrote:

That would be the case if the resistors were integrated in the switch.

Have you established that there is a separate resistor pack? (It is often located in the cool air stream to help cool them)
Assuming it is the switch, I would suggest replacing it rather then trying to fix it. I have never need a car switch that was going to be easy to fix. Be sure to use a the special grease made to electrical contacts if you decide that is needed.

--
Joseph Meehan

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In alt.home.repair on Sun, 22 May 2005 10:38:25 GMT "Joseph Meehan"

True, but they're not. They're under the dash, below the glove compartement, with the resistors themselves in the air duct from the outside. I think that is to help cool the resistors, which in my GM cars were just wire coils suspended in air, with no non-conductor surrounding them.

LOL. I just said that!

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meirman wrote:

Usually the speed is controlled by seiries resistor with taps. Actually the switch itself is changing the position of tap. Tried local wrecking yard? Hard to believe #2 position contact is worn to a point of high resistance with high current. Maybe something wrong with wiring harness? Tony
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meirman wrote:

I'm with the others-- it isn't the switch. Now that you've got the switch apart, I suggest you just stir up the grease as you did. If you want to clean it, spray it with WD-40, then regrease with a silicone grease-- bicycle grease would be great.
I go along with Meehan that it is the resistor. If there are separate coils in the fan motor to change speeds, a coil could be burned out, but that isn't likely.
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This advice does not seem appropriate to me - grease on the switch contacts is NOT a good thing - a little grease on the rocker is OK, but only there.
I would suggest cleaning the contacts with CRC, apply a little high melting point grease (silicon?) to the rocker bearing surface, and reassembling.
David
"George E. Cawthon" wrote:

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quietguy wrote:

The CRC would be good, You want to get all that WD-40 or whatever out of there, followed with some real contact grease. Most auto shops carry it today in small tubes for "lamps and connections"

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Joseph Meehan

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In alt.home.repair on Sun, 22 May 2005 10:40:55 GMT "Joseph Meehan"

Didn't know that. Good idea. That's another place I've seen grease, you remind me. Inside lamp sockets, those that face tghe outside, like turn signals.
Since that is not the usual case with these sockets, maybe the grease is added to lamp sockets when there is water present that the mechanic can't stop. ????
As to the heater switch, I did note during testing today that between speeds 1, 2, 3, and 4, it makes the connection with the next speed setting before it breaks the connection with the current one. Seems to me this should cut down arcing to zero or near zero. Except between off and speed one, which is the lowest speed using the least current. Of course the design must not be as good as I'm making it sound, or these things wouldn't be breaking all the time. (The model from my friend's van may be the more recent one, and maybe it doesn't fail like the old one did. Still, cars have had heater fans speed switches since 1950 and earlier, and one would think they'd have the bugs out by now. My car only has 76,000 miles.
I apologize but I may not have to regrease after all, and I won't if I don't have to because I don't want to open the switch more times than necessary, and break the metal tabs that hold the switch together.
I tested it today with the heaviest 12 volt load I had handy today, and that was a diaphragm-style air compressor suitable for refilling flat tires. Nowhere near, I think, as big a load as the fan, but it worked fine, and I couldn't even hear a difference in speed from the other switch positions. (I wasn't using any resistors.) If I had had 10 more minutes, I could have installed the fan (if I didn't connect the hot/cold lever) but something came up.

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meirman wrote: ((snip))

Boy are you optimistic! I've had older cars most of my life, getting them at 50,000 miles or so (5-10 years old)and getting rid of them at over 100,000 (12-29 years old). Only recently have I ever had a problem with a heater switch. It was a car 9 years old with about 40,000 miles on it.

Glad to hear the switch is working, now to find out if that was really the problem.

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One more point I don't want to be missed.
If there were an open in the resistor block, if speed number 2 didn't work, then neither would speed number 1 (or speeds number 3 and 4, depending on the design, although of speed number 1 is the lowest speed, the simple design will probably always be like mine is.)
When I first diagnosed this, somehow I couldn't feel the air blowing in speed 1, but it was.
That means it is the switch which is the problem.
And if I didn't say it already, the switch is designed so that in all but from Off to speed 1, it makes before it breaks, which I think would reduce to near zero the amount of sparking.
More below, continued to the end.
In alt.home.repair on Mon, 23 May 2005 04:07:50 GMT "George E.

Yes, I am. It's quite amazing at times. (And yet I can also be cynic.)

A sad commentary on car construction.

Well, I wasn't convinced it was working when I posted the above. I've tested things before and had them work on the bench but not where they were supposed to. And this one passed the test, minus the air compressor, the last time.
But today I put it in, and it works. If it breaks again, I'll try to let you guys know.
I've been repairing things since I was 7 or 8, and for the first 9 years, more than half the time, all I did was take them apart, put them back together again, and they worked. Not only did I not know why, I was pretty sure I didn't do anything that would make them work.
That's happened since then too. When it does, sometimes it's mystical. It's almost like I can lay hands on the thing and it will work. :)
I know that I'm not the only one with this experience.
Basically that's what happened the second time I took this control unit out. The first time I cleaned it, pushed aside the hard grease, but this time I really did nothing. I just made a bunch of measurements, took the switch out of the unit and put it back again, made more measurements. (and the one test).
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Obviously you 'feel' a grungy contact is not good. It's called being an old wife and promoting tales. It's dirty. Therefore it must be bad.
As posted previously by others, that grease heavy on contacts is there for good engineering reason. First learn how contacts make and break electricity before just wildly speculating. But to make it simpler to understand: remove grease on those contacts to make switch fail fast.
Stop 'feeling' a conclusion. Stop using old wife reasoning. Or even better, first buy new switches, break them open, and learn before posting. Or read the informed post by George E. Cawthon. High current contacts require a heavy glob of grease (or something equivalent) to last. Did you also know there are two types of switches and relays? Some that can break a current. Others that can only be switched when no current flows. Only the naive would assume 'dirty' means 'bad' - just like myths from an old wife.
quietguy wrote:

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w_tom is an idiot. Many types of grease are not dielectric in nature. They may not mention this on thier labels. Some are dielectric when fresh, and become conductive as they oxidize.
rusty redcloud.
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When did w_tom suggest tossing just any old grease into the switch? Everything that he said should make sense to anybody who is evenly marginally sentient.
======================== Red Cloud lashed out: w_tom is an idiot. Many types of grease are not dielectric in nature. They may not mention this on thier labels. Some are dielectric when fresh, and become conductive as they oxidize.
rusty redcloud.
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Where did he specify what grease to use? Is bear grease okay? Vaseline? bacon fat? Please tell me where he said anything other than just "grease", which could be a lot of different things, many of which would be very BAD to use.

How so? He essentially said to smear on a glob of any old grease you have laying around. He did not say to use a specific kind of grease or even what properties it should have.
Give your head a shake. You truly need it.
rusty redcloud

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