Head light issue

[Armyvet]

Been working on vehicles since the 70's finally came on something that has me stumped. Pulled old 2000 ram out of barn for son to use and seem to have head light issue. Started out as low beam light driver side would not come on, tested and replaced all fuses, looked for any obvious corrosion or broken lines and found none. Also checked wiring in steering column and found no issues. Move around cable harness to see if this would a reaction. NOPE. Just out of curiosity turned lights on and pulled fuse for right side headlights out. WTF. All of a sudden all four lights came on including right side which has no fuse in holder. Before this tested line for left side low beam and had no reading on meter and the continuity tester showed nothing. Bulb in tester is working tested it on right side lights and battery. Also checked light switch. Wire for low beam is violet with white tracer line. I am stumped folks any ideas would be appreciated.

 

[EvilSpirit]

Pulled old 2000 ram out of barn

Wouldn't surprise me if you have rodent damage to wiring harness.

Hard to say without a wiring diagram in front of me, but it sounds like you have lost the headlight to chassis ground, so the headlights are searching for ground back through the circuit. I'd look for either corrosion where the headlights ground, or for vermin damage to the harness.

 

[dudeman2009]

Hard to say without a wiring diagram in front of me, but it sounds like you have lost the headlight to chassis ground, so the headlights are searching for ground back through the circuit. I'd look for either corrosion where the headlights ground...

The bulbs are provided ground by the headlamp circuit, they are connected to battery positive at all times on the bulbs ground pin.

You've probably got an issue with the wiring if one headlight works but the other doesn't. Otherwise, the headlamp switch is a common failure in these. The rodents thing is also a possibility.

 

[sbarron]

Like dudeman said, headlight switch is a very common failure in that generation.

 

[Shadow_Death]

The bulbs are provided ground by the headlamp circuit, they are connected to battery positive at all times on the bulbs ground pin.

You've probably got an issue with the wiring if one headlight works but the other doesn't. Otherwise, the headlamp switch is a common failure in these. The rodents thing is also a possibility.

People say that but my 96 isn't wired that way. My ground is a negative at all times and my other two wires are ground until activated then they turn into powers. This is on my stock wiring harness. Is this positive ground something they started doing after a while?

Edit: I did some quick Google Fu and discovered that the 1996 year model did in fact ground these lights to a negative chassis ground.

 

[dudeman2009]

People say that but my 96 isn't wired that way. My ground is a negative at all times and my other two wires are ground until activated then they turn into powers. This is on my stock wiring harness. Is this positive ground something they started doing after a while?

Edit: I did some quick Google Fu and discovered that the 1996 year model did in fact ground these lights to a negative chassis ground.

I took a look, yeah its a different bulb than the newer ones. They are always grounded, and switched supply.

 

[Shadow_Death]

I took a look, yeah its a different bulb than the newer ones. They are always grounded, and switched supply.

Yup tonight will be fun because I'm working in my sport headlights. This means I will have to wire the 9007s as a positive ground and my 9004s as a negative ground.....

Actually... hell I can just reverse the polarity while I'm wiring them in.