[Proud]

I know I posted this problem in Feb 04 and it has been 8 months since I had the sending unit replaced and I have not had the problem since. Happy to report.

 

[bignoid]

Well what will happen if this is not fixed

 

[froggy81500]

Thanx In2Deep, the part was listed under "Chrysler" not "Dodge". $15.00. I'll probably order one next week. Maybe I'll have time during Thanksgiving to put it in. So are there any "rocket scientists" here that have any explaination as to why this problem is happening?? Why does the plug need a vent?

 

[Chrytech]

The "Vent Wire" has nothing to do with venting air. It's a modified resister.

i dont ever recall it having a resistor

 

[belleaudb]

The vent wire is simply that, a vent. It's just a wire that allows the weatherpack connector to vent pressure. The reason they use a wire is it's cheapest and doesn't require a special connector with a filter and keeps the connector dry. It would take quite a long time for moisture to wick it's way down that 12" of wire. Weatherpack connectors are quite air and water tight.
The switch has only 1 terminal on it. The body of the switch grounds through the engine. When the oil pressure is low, the switch closes and completes the ground circuit for the oil light. This is a simple on/off switch that is calibrated to close at 4psi. It is not a variable resistance sensor. If our cars had oil pressure gauges instead of idiot lights there would be an oil pressure SENSOR instead of a switch.

The vent wire doesn't connect to anything.

In the 80's we had the same type of problems with the 2.6 Mitsubishi engines the Chrysler used in the Caravans, New Yorkers and K-cars. The oil light would be on at idle. The fix then was to loosen the philips head screw that held the blade terminal to the switch. This would allow trapped air out of the switch. Of course this had to be done with the engine running for the air to purge.

On my car I replaced the switch and installed the vent wire. Since the old switch had 135,000 miles on it and it was easy enough.

 

[froggy81500]

Yeah belleaudb. I understand how the pressure switch works. But in my car years I've never seen anything like this before. It must be something to do strickly with long highway driving. Last night I drove to the hospital to visit someone about 20 minutes away. And as is the case, when I got into the city, every stop light the damn light would flicker. But, on my way home, the engine still hot, It didn't happen a single time. Not even when I got off the highway and pulled into my driveway. Left the engine running while I ran in the house to get something and it never once came on.
I have seen this vent tube or wire, on my wife's '98 sebring. I could never figure what it was for since I could only see the open end and not the other where it went tver the weekend I think I'm just gonna drill a hole in the connector until I order the vent.

 

[Bad Intentions 2001]

I have an 2001 Se model that is doing this oil light flickering issue..I just had my oil pan replced a couple of weeks ago and this has started to happen now but only after i come off of the freeway and i am at stop or really low speeds..It does not do it during basic driving..Am i dealing with the same issue as above you guys think or something else? thanks for replies

 

[slowbra]

Most likely the same issue. Have your oil pressure checked just in case.

Why was your oil pan replaced? I'll guess drain plug problem??

 

[Bad Intentions 2001]

Yep the drain plug issue i see that everyone else has had i guess..I printed out this stuff so i will take it down and have them look at it..This way i dont get hosed on prices for my ride..Thanks for help and info..

 

[froggy81500]

Well that settles it. Last night I unplugged my oil switch to get a look at it to see what needed to be done to add a vent. Well the inside of it had oil in it. And there was oil seeping out from the open connection on the switch too. And I know there shouldn't be any oil in that side of the switch. The plug must seal it pretty tight because I haven't seen a single drop of oil on the ground yet, even after pluggin it back in. I ordered a vent and a new switch last night on newmoparparts. Now I have to wait for them to ship. And you can reach the switch from up top. Its tough to get at but I squeezed my arm between the cat and the head and found it without getting under the car. Took me a little while to figure out how the disconnect it without seeing it but I did. I plan on trying to swap out the switch from up top also. That might prove more difficult to get it threaded in there right.

 

[simatree2]

Thanks to all!! I am new to this site-- and I have been having a problem with the oil light flickering only when I am stopped at a light and have my foot on the brake pedal. I have worried as to what the problem was?? Thank you again.. Now with my new found knowledge I will purchase the parts myself and take them to my mechanic for installation..Won't he be surprised that this girl knows something about cars and refuses to get scr**ed.. Will keep you posted as to what the final costs will be

 

[slowbra]

Welcome aboard! Glad we could help.

 

[froggy81500]

Well, got my parts today and swapped out the switch and installed the vent wire. It took me about an hour, including 20 min to the parts store and back to get a 1 1/16" deep socket to fit and about another 15 to degrease the engine. Couldn't get at it from the top, not enough room to get the wrench in there. The old switch had a lot of oil in and around it. And I mean inside the electrical connection. That vent is actually a wire. I thought it would be like a hollow piece of tubing or something. I have no idea how its supposed to vent anything, unless, as someone else in this thread said, it acts as a heat sink to draw heat away from the plug. I dunno. Took it for two short highway test drives and so far no light. Keeping my fingers crossed.

 

[peva]

...That vent is actually a wire. I thought it would be like a hollow piece of tubing or something. I have no idea how its supposed to vent anything, unless, as someone else in this thread said, it acts as a heat sink to draw heat away from the plug. I dunno. Took it for two short highway test drives and so far no light. Keeping my fingers crossed.

It is a vent. There are small spaces (called interstitial spaces) for air to move thru in stranded wire. We're not talking about huge flow rates here - just enough to vent pressure due to temperature changes and v-e-r-y slow oil seepage.

 

[slowbra]

Still not buying that theory completely. As you can see, the wire strands are crimped into an electrical connector. No need for the wire if we're talking about seepage through an interstitial space, since the back of the connector is wide open already, and there would be no pressure even getting to the wire to seep through. There's got to be another explanation to this. I'm guessing that if there is nothing electrical or anything to do with resistance, then it has to do with the connection itself and how it attaches to the sensor.

 

[Communicator7]

I've read this whole thread from page 1 to page 4 just now. I've always disregarded the oil flickering light issue because I've never had it happen to me.

What I want to know is, on my 99 2.7L Trep, what happens if I don't fix this? As long as this oil light doesn't flicker, I'm ok right?

 

[froggy81500]

Honestly, I don't think you're in any danger if you don't install this vent. About the only thing that might get damaged is the oil pressure switch for the dash oil light. I think the whole purpose of this vent to prevent pressure building up in the switch and ultimately causing it to leak and misrepresent the oil pressure in the engine. I had to replace my switch because it was leaking. I think that it might have started to leak months before I started getting the oil light flicker. Keep an eye on the underside of your car, especially on the passenger side and on the sway (stabilizer) bar. Thats the first place I ever noticed any oil well before the flicker. since I replaced mine, no more flicker and everything's clean underneath. Oh and my '01 started the flicker at 57K miles around Thanksgiving. Been trouble free now for nearly 6k miles and got 63K + on the clock.

 

[peva]

Still not buying that theory completely. As you can see, the wire strands are crimped into an electrical connector. No need for the wire if we're talking about seepage through an interstitial space, since the back of the connector is wide open already, and there would be no pressure even getting to the wire to seep through. There's got to be another explanation to this. I'm guessing that if there is nothing electrical or anything to do with resistance, then it has to do with the connection itself and how it attaches to the sensor.

Either tell me in words or show me in a photo at what point the seal on the back of the connector seals around the insulation - then I'll address your comments.

However, regarding where you said "...then it has to do with the connection itself and how it attaches to the sensor", to repeat what I said in the thread a few weeks ago (http://www.dodgeintrepid.net/forums/showthread.php?t=50618&page=1&pp=15&highlight=vent+resistor) where we got into this that there is no electrical connection to the sensor by this wire - it electrically connects to *nothing* on either end. Nor does it connect to the sensor mechanically - it simply locks into the connector and gets sealed around the wire/vent insulation (so that any air trapped in the otherwise sealed connector can leak out without allowing moisture in).

From that other thread:
To go along with my explanation about the unused cavity, below is the schematic of the oil pressure switch wiring. There are two cavities in the connector. Only the one cavity used by the circuit is shown. The unused cavity is where the wire/vent gets installed. It electrically connects to nothing. While hopefully preventing any water from getting into the connector, it vents any pressure within the connector/pressure switch air pocket due to switch seepage or temperature changes so that pressure doesn't feed back into the switch and shift its switch point. It does nothing electrically.

I appreciate the civil discussion on this - I've learned some things every time we talk about it. It would be a very good thing if you do show at what point on the wire the connector seals around the insulation. I'm betting that the seal point is to the left of the insulation crimp in your first (top) photo, in which case, it would work as a perfect vent. Don't let that crimp on the insulation fool you - there's still plenty of room between strands of wire to sneak thru to equalize pressure.

 

[slowbra]

You explanation makes perfect sense in some regards, but I still don't understand why it would take 2 feet of wire to accomplish any venting of what would really only be an air pocket. Doesn't make sense...but that's nothing new in the automotive industry! :biggrin: We'll keep digging!

 

[peva]

You explanation makes perfect sense in some regards, but I still don't understand why it would take 2 feet of wire to accomplish any venting of what would really only be an air pocket. Doesn't make sense...but that's nothing new in the automotive industry! :biggrin: We'll keep digging!

The only thing I can figure is the excess length is there to give a reasonable chance of keeping moisture from making it back into the connector air pocket (i.e., it would get baked out before it made it all the way there). The bend at the far end creates an inverted trap (again, to keep moisture out). The overall goal of the length and the bend are to create what in the seal engineering world is called a "circuitous path".