How does the air pressure switch in the tire???

I was wondering how the air pressure switch works in the tire???
Does the car have to be moving for the switch to work or should the light come on anytime the tire is low? The reason I am asking is when I first got my Dodge the light was comming on for low air, after checking all the tires the air was good but the light still came on. So I took it in to be fixed, I got it back and after a trip in to Vegas it came on again. So back to the dealer I went, this time they had it for 4 days.
Got it back and the light has not come back on. But me being a smart AZZ said to myself, I wonder if they just bypassed this thing??? So I let two of the tires down to 10 lbs of air, then started the truck put the seat belt on. just to make sure they were not tied together some how. Still no light, my question is to you guys is, should I be seeing a light now??? I think they bypassed it,:rolleyes: don't you???
Kurt

If you find out that they did that----I hope you turn them in to the feds

They are pressure sensors. They tell a computer how much air is in the tire and what the temperature of the tire is. They have a threshold usually around 25psi that the pressure must reach before the light comes on. If the light is blinking, they is a malfunction which most times means one of the sensors needs to bereplaced. They are battery operated and the batteries cant be changed

Thanks Guy's; I had two tires down to 10 lbs. and nothing came on or happened.
No lights like before no whisles and no bells.
So I think thats what they did, they disconnected it.
If you can't trust the dealer who can you trust!!!!
Kurt

Kurt,

Take it to a different dealer or better yet, a reputable repair shop, tell them that you had a tire that was half flat and the light did not come on. If they tell you that it is disconnected, then you have some ammo for the other dealer. Your luck, all they did was loosen the bulb (if they can) and left it place. That way all they have to say is that the bulb must have fallen out.

My ex has a car with the tire pressure sensors. Hers keep going on all of the time. They tell her that the temperature changing will set it off. Especially if it is warm to hot during the day and real cold at night.

I was told that in order for the light to come one, only one tire must be low. If 2 tires are low the same amount , the light probably won't work.

Bug; I don't think they loosened the bulb because when I turn on the ignition the light goes on but then goes out with all the other warning lights.
Sunsetdart; I let the air out of the tires one at a time, I wanted to make sure that one of the sencers were not bad.
They were all set at 46 lbs. so a 36 lb. drop in pressure is a big one for the sencer's not to go off!!!
The wife said to go to the owner of the dealership, I told her do you really think he does not know what's going on???
They are trying to save money because it's under a dealership warranty right now!!!
I think they were trying to pull a fast one, on me.
Kurt

I have 35, 35, 33,33 in my Dodge , the pressure needs to be lower to trigger the warning Mine will tell what is in each by location

53 Willys; The weather here has been really mild so I don't think that is a issue.
Me lettting out 36,lbs. in two differant tires should have done the trick.
But the light didn't come on like it was doing before.
I think after two try's of them trying to fix the problem and not being able too they got frustrated,
and then just disconnected it.
Kurt

Kurt..................I would take it back to the dealer. If it's under warranty, they have to fix it.

I know things change but I have a 90 vette and I was told it works like a barometer. there is what looks like a large hose clamp holding the thing to the inside of the wheel. mine will come on showing a LTPWS sometime when one of the sensors fails. you can do a search on the web for LTPWS on Corvettes lots of stuff out there about them. to bypass the light on the Vette all you have to do is remove the cruise control fuse lol.

I know most don't car for Chilton's repair manuals but here is a way to view online some may have saw it before. maybe a how to there
go to this link and logon as a123456123456

https://elibrary.mel.org/validate?ur...ch%3Fdb%3DCHLL

I'm with sunset, take it back to the dealer.

Years ago I had a new Mercury Topaz. Drove from Seattle to San Fran. On the way back it started to lose power and finally could get no more than 40mph out of it. Took it to the dealer the next day and they said the cat converter was clogged and I must have put leaded gas in it (some leaded gas was still available back then). I told them that was impossible as I was the only one filling the tank and since it was still under the 50,000 emission warranty they had to replace it. Got it back and it ran fine and even passed the emission tests for several years. Then one year it wouldn't pass so I took it to another Ford dealer, they checked it and said someone had gutted the Cat converter. Took it back to original L/M dealer where it was purchased and told them to replace the gutted Cat or I was going to the State AG. They replaced it that day and the next day it passed with flying colors.

I now own a 2006 Charger RT Hemi, Bought there $399 lifetime oil service deal, We keep our vehicles a very long time, still driving a 95 Dakota and a 96 Intrepid, and have been changing the oil and filter every 3000 mi. or 3 months whichever comes first as per the $399 deal for 3+ years now. This last change I was informed the trans needed a service for $400 so I asked why as the owners manual calls for a service after 60,000 mi. Was told the fluid was low. As some of you may know Chrysler products no longer have a trans dip stick and the trans is no longer serviceable buy the owner. Went to the Charger forum on the web and found out the trans in the Charger is a mercedes so all that is needed is to get a Mercedes dip stick. Did that, checked the fluid and sure enough it was down almost a qt. Now it was fine for the last change and we had put less than 500 mi. on it since the last change and it doesn't leak a drop anywhere. Anyway I filled it myself and am interested to see what they find wrong when I take it in next time and I am sure it didn't leak nearly a qt. in less than 500 mi. Long story made just a bit longer, I don't trust dealers. The dodge dealer figured out that in my case that my $399 deal for them is going to be a loser for them and are trying to recoup their loss. Sorry for the rant.:mad:

Jack.

Kurt.you have to drive it for a bit to get the light to comes on, it won't come on if you just let some air out and then start the engine. Also be aware that the spare usually has a sensor also. And on a third note those sensors will not tolerate moisture,hence the need for nitrogen to fill your tires unless your sure you got no moisture in your air compressor system.

I got caught in my Focus on the interstate with a flat tire so I blew in a can of fix a flat, later had the tire removed from the rim for repair and the fix a flat is like water, sitting on the bottom. The low tire sensor didn't doesn't seem to mind the liquid. :HMMM: It's still working. :HMMM:

I will say that mine activate at 20 psi. And even after filling the tire back to 35 psi, the sensor takes like 1/4 to 1/2 mile to reset.

I went in to the dealer today and asked him if the tire pressure was down to 10lbs should the light go on and he said yes.
I said well when it didn't go on for that one I filled it back up and let the air out of a differant tire and it still didn't go on.
He said bring it in thrusday and we will take a look at it, He said it looks like the computer didn't down load the info
from the 4 new tire sensor's he said they put in. I have to ask myself don't these guys check it out to make sure it's
working after they do the work of breaking down all the tires to put new sensor's in???
Kurt

Do you really believe they installed 4 NEW sensors??? I do not!

Don't mean to hijack, but on a related note my daughter's GMC Acadia has the sensors and kept signalling that here left rear tire was low. I checked it and aired it up to 40 pounds. She came back later and said she is still getting the message at she only has 25 pounds in the left rear. I checked it again and found it was still at 40. so I checked them all and found her left front was low, 25 pounds. Aired that one up and the message went away. Just wondering how the computer knows which tire is which? She had work done recently and I wonder if they moved the tires around.

Pat

They have to be put in the computer in the right order.
That means if you rotate them they will be out of order.
Kurt