Questions and problems

[GLack]

I have an '05 4dr with the 6 speed manual, "tow package". I bought it new and no modifications have been done to it other than putting a shell on it in 2006 with a brake light in the upper middle back of the shell. The shell was put on by the company selling the shell and looks professionally spliced into the wiring at the driver side rear break light. It gets driven very little, right now it has 29000 miles. The problem is both brake lights come on when it is parked, all on their own at unpredictable times, usually overnight. This started back in 2009. I did a temporary fix by taking apart the brake switch attached to the brake pedal. This worked for about a year. The problem started up again 6 weeks ago. I have now replaced the break switch under the dash. Very easy to do, so I know I didn't screw that up, yet within a day or two I came out in the morining and the brake lights were on again. It has now stopped again for the last few weeks. Is this a Dodge problem anyone has heard of? And no, the break pedal is not making contact when the lights go on. And no, it is not a joke by a friend because when it started up again I was about 500 miles from home. Also, two questions for anyone interested. I am running Mobil 1 synthetic motor oil since my last oil change. Opinions on synthetic oil for Cummins and how long to let it go before changing it. Also, I was thinking I could increase my mileage by putting an OD on the 6 speed, especially since I have a very low (4. 21?) rear end. Good/bad idea? Why? The cost is prohibative but I am more worried about damaging the transmission. Better alternative to improve mileage? Right now the engine is doing about 2500 rpm at 70 mph. I would like it to be closer to 1600 to 1800. And I have thought about large tires. Ideas and facts would be greatly appreciated.

 

[HBarlow]

Try pulling the slip on wires off the brake light switch or just pressing and releasing the brake pedal next time the brake lights are activated while the truck is parked.

Also pull the left rear taillamp housing and inspect the connection for the camper shell stop light wiring. The most suspicious component in a truck with a problem is usually where the aftermarket product is involved. If the installer didn't carefully isolate and insulate the add on connector it might be touching something it should not. If not sure, cut or disconnect the camper shell wiring and leave it off for a while.

Your truck probably has 4. 10 gears which are perfect for a truck used for towing a heavier trailer. 3. 73 gearing will be a tiny bit more fuel efficient for highway cruise if you never tow with your truck. The real world difference in fuel mileage between 4. 10 and 3. 73 will be tiny. Not worth spending any money to changeover.

 

[GLack]

I did originally take off the tail light assembly and checked the splice. It was well insulated with tape. I did read yesterday in TDR someone a few weeks back had an electrical isssue in their dash when an iPhone charger was plugged into a "door mounted charging outlet"(?). I don't have an iPhone but I do sometimes leave my cell phone charger in the lower, driver side dash power outlet. I will experiment with this and see what happens and if there is a correlation between leaving the charger in the outlet overnight and the brake lights comimg on. Why this would make the brake lights come on is beyond me but having had issues with Chrysler engineering in the past, it would not surprise me at all it is another Dodge HUA problem. I swore I would never buy another Chrysler product except for the fact that this truck does not have a Chrysler engine or transmission. And as we all know, Cummins is the gold standard of diesel engines. I would have bought a Yugo if it had a Cummins motor in it. Thanks for the response.

 

[RustyJC]

Being a 2nd generation owner for the moment, I'm not certain of the following regarding your 3rd generation truck, but if you have a schematic of the wiring, check the location of the brake light switch - is it in the "hot" or "ground" side of the wiring? Dodge has a tendency to locate switches in the "ground" side which, if that's the case here, means that power is present on the "hot" side of the brake light circuit at all times, and the brake light switch merely has to complete the "ground" circuit to turn the brake lights on.



Although there are advantages to this approach, the downside is that a short to ground anywhere in the "ground" side of the wiring will energize the circuit. Therefore, any nick or rub (or bad connection to the shell) in the brake light ground wires up to the brake light switch that short them to ground would result in the brake lights being turned on.



Rusty

 

[GLack]

Thanks for the reply, I just logged back on. You sound much more knowlegable than I on the subject so maybe you can make sense of it. It appears the problem occurs when I leave my cell phone charger in the lower dash outlet overnight, w/o the cell phone attached. Is this something you have heard of? I have a very high opinion of Cummins but not of Chrysler. I believe the bozos at Chrysler should be horsewhipped every so often just to remind them that their customers should come first and what they design they should stand behind. So a bizzare electrical issue from these knuckleheads would not surprise me. Anyway, any info is appreciated.

 

[SSolderitch]

The brake lights are switched on the hot side. When the lights are on - pull the brake light fuse. Are the lights still on? - if yes then you have to pull more fuses to track down the problem and see which other circuit is feeding the lights. if no then pull all the bulbs (tail & cab center & cap) check each socket for one side to ground and other side should be open (no ground and no 12 volts).



Power outlet is not on the same circuit and is not the problem.