Just joined the Chrysler Forum and came across your post. My 96 Saturn SL finally died and my old boss was kind of enough to gift me her 2005 3.5 Touring Pacifica with exactly 180k miles. Pretty clean and well taken care of.


It's a great car, however, the oil light came on for a day several months ago. It went out on it's own after a day so I thought "problem solved". The car had set for 5 months before she gave it to me.


I had thought about replacing the oil sending switch, however, it went out and so I ran an oil system cleaner and changed the oil and filter.


Now 4 months later it's back on. It goes like this: first start on and stays on the entire trip unless you stop and restart. Then for the next 3 starts no engine oil light the whole time running.


So I took the sites advice and replaced the oil sending switch and it was exactly the same. I took it to a mechanic who said try removing the white rubber backing on the back of the connecting clip. (Help it breath or read better?) I did this, see attached, and got the same result.


While I had it up on jack stands I thought I would disconnect the switch and see what happened. It was the same with the oil pressure switch disconnected. The light comes on with the first start and not on the next few. So when it's on it stays on and when it is off it stays off.


Of course my concern is damaging the engine. But now I'm believing it's some sort of electrical problem. Do you have any ideas/suggestions?


Is this a known 2005 Chrysler Pacifica 3.5 Touring problem or issues?


Thanks Brothers,
Getting back on my feet in Kansas City,


Scott


"UberPacifica2005" - From Chrysler Forum

 

Just for curiosity's sake, did you put in a Mopar sending unit, or aftermarket?
Chrysler products only like genuine Mopar sensors and sending units.
I've seen WAY stranger symptoms than yours that boiled down to an aftermarket sensor/sending unit.

 

Yes, I put a $17 aftermarket sensor. I'd gladly buy the Mopar part, however, how would you account for the same symptoms without it connected?

UberPacifica2005

Thank you!

 

You make a very valid point!
There are three major ground wire clusters directly below the battery and they can cause a myriad of electrical gremlins when they get corroded.
It's a good and cheap first step to take.
I hope that helps!

 

Great idea! Will look tomorrow!

UberPacifica2005

Scott/Kansas City

 

Hey Jeep Guy,

Are these the three ground wires you were referring to?


UberPacifica2005

 

Those are the ones.
Mine looked fine visually but once I put a little pressure on them when wiggling the terminal, they crumbled.
I replaced the ring terminals and stripped all the wires back about 1/2" and all of my accessories and gauges worked as intended.
A good coating of liquid electrical tape slathered on the crimp section and in between all of the wires helps prevent this problem in the future!

 

So I found the wire were dry, gray with hints of red rust. I took a wire brush to both the stud and the terminals. I put it all back together and got the same result.

But, I feel like this wasn't wasted time, as in this was probably worth doing and I learned some more about my "new" car.

Hey anyone; is the Pacifica a truck, mini-van or SUV?

UberPacifica2005

 

Among the vehicles in my "stable", I have an 04 Neon 2.0 engine....Every once in a while i'll get the same oil light stays on, shut down and restart...oil light goes out, The 3.5 is known to consume oil, keep a check on the oil level with the dip stick. I've done the ground point connections just as you have done and it did slow down the number (regularity) of occurrences of the light. I THINK the other end of the wires from the press. switch going into either the fuse panel or PCM are the cause by either being a little loose connection. Just don't have the time or schematics to track down the Neons occasional fault, as it's my college commuting son's ride and free days he's on the road with friends and his GF! You may want to pursue this thought of the other end of the wires into the fuse panel or PCM if you can get a schematic for your Pacifica. GOOD LUCK

 

If there was rust and corrosion on the outside of the wires then there is rust and corrosion in between the individual strands of the wires, as well as the points of contact between the wires and the crimped connection of the ring terminal.
All of the sensors work via resistance and all of that corrosion and rust is adding additional resistance to the circuits.
As an electrician I can assure you that getting rid of the bad wire ends and using new ring terminals is going to save you from future issues, possibly at the most inconvenient time.
It's intimidating to think about trying to crimp that many wires into a large crimp for the average DIYer, so I recommend getting smaller(gauge, because obviously the ring part needs to fit over the studs on the car body) ring terminals and putting a few wires in each terminal.
Go to Lowe's or some place like that and go to the electrical department and get an $8 bottle of liquid electrical tape and the ring terminals( the yellow size should fit 4 or possibly more of the small wires each).
After you put on the ring terminals and tighten them on their intended studs give them a ridiculous amount of the liquid electrical tape and make sure to get top and bottom of the crimp section of the terminals and in between each wire, let it start to cure for an hour, then give it another coat of almost the same ridiculous amount.
It will skin over in 30 minutes to an hour and fully cure in roughly a day.
An hour or two of driving might fully cure it as well, but let it skin over before you drive it.

The Pacifica is considered an SUV, but with it's lack of ride height, I consider it a station wagon. Lol
My $0.02

lol