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Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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2005 Dodge Ram 1500 4x4: litre..pickup..tail trailer light

Customer Question

I have a 2005 Dodge Ram 1500 4x4 Quad Cab 5.7 litre hemi pickup. My tail lights havent worked in over a year. I've changed every bulb possible, I've also checked my trailer light hook-up, Same reults. All other lights function fine, including hazards and interior lights. The fuses are also fine.
The only other electrical problem the truck has is the left rear door electric lock doesnt function, but probably unrelated.
The only suggestion I can get at local dealers or mechanics is to hook up to the diagnostics machine at about 115$ an hour. Although I'm confident they can find a solution, I don't relish the idea of spending so much at this time.
Submitted: 7 years ago.
Category: Dodge
Expert:  sprinkles08 replied 7 years ago.

Hello and welcome to JustAnswer!


Do you have a test light to do some testing?


Customer: replied 7 years ago.

I can dig up a multi meter if thats what you mean


Expert:  sprinkles08 replied 7 years ago.

A digital voltmeter will work too.


Have you lost the rear park lights only, or have you lost brake and turn signals also?


Customer: replied 7 years ago.
Just the rear left/right night lights. on the truck, and the trailer. hazards, sgnals, and brakes all work fine. The front lights are also fine.
Expert:  sprinkles08 replied 7 years ago.

Ok. The first thing we need to do is go to the fuse box. Put the black lead of your voltmeter on ground, use the red lead to probe the small windows on the top of fuse 32 with the park lamps turned on. See if you do have battery voltage on both of the small windows. This will tell me if the park lamp relay is sending voltage out to the rear lamps.


Customer: replied 7 years ago.

I used a Snap-on MT370 Voltmeter, New battery. Also tested the voltmeter on functioning circuts. The meter works fine.

As for #32, there was a 10 fuse (red) and didnt give me any volts.. 0.0

For kicks, i changed a few of the other 10 fuses, i received signals when it was elswhere, but none returned a value in #32

Expert:  sprinkles08 replied 7 years ago.

Ok. That means that the park lamp relay isn't sending any power out to the park lights. Let's double check fuse 15, a 50 amp. Check it the same way, installed and probe each terminal on top with the meter and check for battery voltage.


When you turn the park lamps on do you hear the relay inside the box click, or no noise?


Customer: replied 7 years ago.

When I first turned the park lights on I did hear a click. A crunchy sort of click if that makes any scence. I turned it on a few more times through this test and it never clicked again. When I send this message I'll go check if it clicks after waitng.


I took out the 50 amp and without the lights on it returned 1.1 on the voltmeter. There are two prongs, the prong closest to the back returned voltage while the one to the front didnt. Without the 50 amp in its slot the lights still came on in the front as well.


I placed the 50 amp back in its slot without the protective plastic cap on and checked voltage again, it returned a 1.1 on the voltmeter again with and without the park lights turned on.

Expert:  sprinkles08 replied 7 years ago.

Leave the black lead of your voltmeter on ground for all testing. Set the voltmeter to 20 volts DC. Leave the lights off and probe the top of the fuse to see if it shows battery voltage on the meter.


Customer: replied 7 years ago.

- This meter doesnt have a adjustments for volts. It's a Snap-on MT370 if that helps.

- I have been grounding for each test.

- I'll go look in my work-shop for my multi-meter.

- I went back out and checked for the click sound. It hasnt clicked again.


Expert:  sprinkles08 replied 7 years ago.

I don't see that model number on their website, mabye discontinued or superceded model number. That happens alot. If we're unsure of the readings from whatever you are using now we just need either a simple test light or a digital voltmeter capable of testing DC voltage.


Customer: replied 7 years ago.

I just found my OTC 3391 Multimeter.


I'm looking over the manual to see how the wires attach to the device now.

Expert:  sprinkles08 replied 7 years ago.

I'm here whenever you get ready.


Customer: replied 7 years ago.

Ok, did the test.


It reads 7.90


Goes up and down a little but not much more than .10 points

Expert:  sprinkles08 replied 7 years ago.

Let's make sure the meter is set up right, you should have seen battery voltage there. Put the black lead on the ground terminal of the battery, the red lead on the positive terminal. Set the meter to 20 volts DC (not AC) and read the battery voltage. It should read close to 12.6 with a good battery.


Customer: replied 7 years ago.

Directly having the black on the battery negative terminal the maximum reading was 7.76


For a good contact i dug the point in well too. Also made sure I had a good connection to the 50 amp.


As well, i made sure to have a new battery in the multimeter.


I'm sure my truck battery is good. Its older but have never had problems with it. And it gets cold here and never chugs on startup.

Expert:  sprinkles08 replied 7 years ago.
We need to see if the meter is set up right before we test at the fuse because that voltage should not be possible unless you have an internal problem in the fuse box. Put the black meter lead and the negative post of the battery, the red lead on the other post. Set the meter to 20 volts DC and read the voltage on the meter.
Customer: replied 7 years ago.
7.60 appx directlt with red and black on the battery
Expert:  sprinkles08 replied 7 years ago.
If you have 7.6v at the battery there are only two possibilities. The meter is on the wrong setting or the battery is dead. See if the truck starts, and if it does, make sure the meter leads are in the correct position and it's set to 20v DC.
Customer: replied 7 years ago.

- The truck started fine.

- Tested the battery again and it's still the same.

- Disconnected the black on the battery too in case of a bad wire somewhere and still it only read 7.6


I'm going to do the same test on my wifes car battery right now, to eliminate the possibily of a bad setting or bad multimeter.



Expert:  sprinkles08 replied 7 years ago.
If the truck started but the meter shows under 8v there's definitely something going on with the meter.

Since we are showing the same voltage at the fuse as we are the battery though, we know the fuse has power. The next thing you'll need to do is pull the fuse box up and remove the front control module (with the key turned off. This is the silver module on the side. When you get the module off turn it over and you will see the terminals are numbered on the ends. Find pin 15 on the module, and then find it's corresponding terminal that it would mate to in the fuse box. Insert a straightened paperclip into that terminal, and jump the paperclip to see if the park lights all come on.
Customer: replied 7 years ago.

My wifes 2001 Dodge Caravan gave me 7.6v also.


It just got dark out so I'm going to get some ligts. I'll follow your instractions and reply shortly.

Expert:  sprinkles08 replied 7 years ago.
Definitely a meter issue then! I was afraid the battery on the truck was dead at first. I'll be here for the rest of the night, just reply whenever you can. We're getting close, this should be the last thing we need to check hopefully.
Customer: replied 7 years ago.

I gotta shut down for the night. It's dark and pretty cold now.


I'll sign in tomorrow after work.


Thanks for the time today.

Expert:  sprinkles08 replied 7 years ago.
Not a problem. I'll be at work during the day myself, and I'll be online for the rest of the night from about 6:00 Eastern time on. Just come back and reply to this same question tomorrow like you have been today, and we'll get it figured out.