Cleaning electrical switch.

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.

Meirman

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Reply to
meirman
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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 c> This is about about my car heater fan. It's not really about home or

Reply to
Bennett Price

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.

Reply to
Joseph Meehan

Hi, 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

Reply to
Tony Hwang

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

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.

Meirman

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Reply to
meirman

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.

Reply to
George E. Cawthon

Grease is commonly used in high amp switches to reduce contact burning/arcing. Removal of the grease will lead to a short life.

Reply to
George E. Cawthon

look under the hood on right side the is a resi block in the firewall, unplug remove two screws pull unit from fire wall.see if one of them is smoked fried burnt. new block at dealer about 10.00 dollars!!! stan

Reply to
stan hofacker jr.

In alt.home.repair on Sat, 21 May 2005 22:21:14 GMT Bennett Price posted:

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.

...

Meirman

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Reply to
meirman

The OP has already said he's tested the switch and found that position #2 isn't functional (continuous), while the others are. I'd say it's likely the guy knows how to use a meter, and therefore it's the grungy contacts (and maybe degraded spring force) that are to blame.

I had an identical problem with a Volkswagen fan switch. I found the contacts all green & crumbly from corrosion. I cleaned the contacts using Flitz, sprayed it down with contact cleaner (Chem-clean, I think) and reinstalled it. It worked fine from then on, for about 8 years.

I'd say avoid any lubricant at all. Just polish the contact areas & reassemble.

Reply to
Robert Barr

come on now..... if there wasn't supposed to be grease in there, why would the manufacturer put it in there to start with. Even in low amperage switches like "mode switches" in VCR's they put grease in there to not only reduce the friction and wear but to keet the contacts from oxidizing..... put grease in there for sure.... even a heavier general purpose grease would be just fine for the higher amperage and heavier contact spring tension switch like in the heater fan switch. If you run it dry, you will lose the switch in a much shorter time. electricitym . .

Reply to
electricitym

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. Cawth> . Now

Reply to
quietguy

Maybe, but I doubt it. My thoughts are that due to arcing etc the grease that lubed the switch mech has melted and flowed to the contacts, casuing more arcing etc etc

As far as I know grease is an insulator, not a conductor

David

snipped-for-privacy@yahoo.com wrote:

Reply to
quietguy

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.

Reply to
Joseph Meehan

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"

Reply to
Joseph Meehan

Not all grease is created the same. You want to use only grease designed for electrical work. It's cheap and you can find it at the auto parts store.

Reply to
Joseph Meehan

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?

Reply to
Doug Miller

As far as I know grease is an insulator, not a conductor

==========

You will discover that manufacturers and wise repair people use grease on many electrical applications.

Watch a pro work on an automobile "no start" problem and you will most likely see him remove, clean and grease every contact in the high current starting circuit. Proper operation of the circuit isdependent upon extremely low resistence and the grease is there to prevent the corrosion which will ruin that low resistence circuit.

Once again, as others have said, the optimal goal is to restore the switch to the same condition that it was in when fresh from the manufacturer, or install a replacement switch which meets that condition. The OEM switch has a particular type of grease in it. It is there for a reason. Emulate the manufacturer and do the same.

Gideon

Reply to
Gideon

You are good some good advice here, which doesn't surprise me.

But you may still want to post the same question over at rec.autos.makers.chrysler rec.autos.tech

The folks over there may offer more experience with this particular problem. You may want to cross-post to those two groups. You may also cross-post to alt.home.repair & sci-electronics.repair since some of us are interested in the opinions on this topic.

I've seen discussions before on your problem, which appears to be well-known and common. You'll want to check the resister block PLUS all electrical connections between the fan, resister block and the blower motor. Sorry, I don't remember more on this issue since I don't follow the auto groups on a regular basis. I do remember that the "high" fan setting is usually the last to fail since it is the setting which doesn't depend upon any resistors to limit current.

You could also try a "Google Groups" search to check on past newsgroup discussions of this problem.

In your situation, I would:

1) Research via newsgroup questions and Google searches. 2) Clean switch contacts and reapply grease. I'd use a bit of PERC on a Q-tip to remove grease from contacts. PERC is available in some versions of electronics cleaners. It is also available in the "chlorinated" versions of brake parts cleaners (on sale currently at Car Quest for $1.59 per can). I'd clean contacts with a bit of Lime-Away on a Q-Tip, followed by a final cleaning with PERC on a Q-Tip. (I buy cans of "chlorinated" brake parts cleaner by the dozen when it goes on sale). 3) If possible, check ohms on every resistor in the resistor bank. Verify these readings against a published reference. Or go to the dealer's parts department with your ohm meter to get some reference readings. 4) Clean all electrical contacts in the switch-resistors-fan circuit. Apply good grease to all contacts before reassembly. 5) If this doesn't help, I would also attempt to "jumper" across switch position #2 to see if that runs the fan. If so, then it would identify that the problem is in the switch. If not, then there is a problem elsewhere - a bad contact or a bad resistor. Always attempt to eliminate variables in this manner.

Good luck, Gideon

Reply to
Gideon

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.

St> This advice does not seem appropriate to me - grease on the switch

Reply to
w_tom

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