1999 Dodge Dakota 5.2L V8 4x4 5spd Manual

When the parking lights are on and I turn on either blinker or the 4-ways my parking lights/license plate lights are also flashing opposite of the normal blinkers.

i noticed it well checking my trailer lighting. Problem still exists even with trailer and tail light harnesses unplugged.

My reverse lights also do not work but I believe that’s the switch in the side of the trans.

 

You have a bad ground. Check all the wiring especially the trailer wiring.

 

Like I said, I disconnected the trailer wiring to rule that out. Do you happen to know locations of grounds? Any common ones that fail? Definitely some rust on this truck

 

Yes that is a ground fault. What is actually happening is that your turn signal is "grounding" through the park lamp circuit. I have actually done that intentionally on Dually's to make the fender clearance lights flash with the turn signal to get people's attention when towing a trailer obscures the truck's taillights.

Just to make sure...you don't have LED turn signals or parking lamps, right?

These diagrams are for 2001, but yours shouldn't be much different.

Here is the trick... Grounds 112 and 113 are up by the battery. Yes, the taillights ground at the battery. Nobody said it made sense.







So..the technical explanation.

When the ground fault occurs, the lamps create a "voltage divider".

Also, voltage is relative. Many circuits are at ground-potential when they are not illuminated.

So what happens, when the circuits have a like-ground but it's not at zero volts potential...

12 volts is applied to the turn signal. Those 12 volts are then shed across the resistance of the filament, and have a choice. They can take a high-resistance route through the formal ground to the battery, or the less-resistance route through the parking lamp circuit, to the combination flasher. Because the turn signal filament used up all the voltage, there is not enough to light up the parking lamps.

12 volts is applied to the parking lamp. Those 12 volts are then shed across the resistance of the several filaments, and have a choice. They can take a high-resistance route through the formal ground to the battery, or the less-resistance route through the turn signal circuit, to the combination flasher. Because the parking lamp filaments used up the voltage, there's not enough to light up the turn signals.

And when you have parking lamps turned on with a turn signal on, usually you'll either get a constant-on or constant-off effect. Likewise if you press the brake with turn signal on.

 

Thank you very much for the info. No LEDs in the mix. I’m going to polish up every ground. No better place to start then with brand new battery cables. Mine look like they came out of World War II.
I’ll update you in a few days once I get time to get a new cable and all the grounds cleaned up.

 

All the grounds I could find have been cleaned, and the truck has new battery cables (Positive, and Negative) I also fixed my reverse lights with a new switch in the side of the trans.

But the lights still flash.
Think the Multi-Function Switch could be it?

 

I would find it doubtful that it could be the multi-function. This kind of issue is in the wiring, because the parking light circuit has nothing to do with the ground circuit.

I just realized yours is a 99. My diagrams are for 01. Your truck should have a standard EP27 flasher module I believe.

Just for grins: Is it possible that you have installed a CK-wired bulb somewhere in the system instead of a non-CK bulb? The wiring is different and can create a short across the two circuits.

 

What type of trailer connector are you using for your trailer light connection? Many years ago, I had trailer brakes that worked fine normally. However, I had an issue come up after the rig was in service for a while. Running without the trailer, no problem. Running with the trailer, the brakes starting engaging with the left turn signal. After a day of tracking the problem, it came down to my vehicle end of the wire connector. The wires were held into the connector by screw connections. Water had run down the wire into the connector and rusted a screw. The rusty fluff caused a short and was the problem cause. I cleaned everything, packed dielectric grease between the wires and wrapped it heavily with electrical tape. I use different connectors now.

 

All Taillight harnesses & trailer wiring harness were unplugged and it still had the issue. So taillight wiring, taillight bulbs, and trailer wiring are not part of the issue.
🤔🤔🤔 Going to have to pull wire loom apart and see if I find anything fishy

 

If the wiring on the vehicle end of the trailer wiring has been removed from the circuit, then you definitely have a ground issue. Make sure all your grounds are good. Besides the major ground cable to the engine, you have one to the fender and one or two from the firewall to the engine.