Passenger Side Headlight Dim

[bh115577]

The headlight on the passenger side is dim on both high and low beam. Driver side is fine. Tried several new bulbs and even switched them from side to side to double check. I've cleaned every ground I can find, even looked under the dash, but nothing seems to make a difference. This is a 2 headlight system, not the quad setup.

 

Any thoughts on this? I can't afford to lose anymore hair.

[dripley]

Have you cleaned the connections to the headlight itself? Sockets, plugs, and etc?

[bh115577]

There was some corrosion at the headlight plugs so I replaced the pigtails, solder and heat shrink, with no change.

[dripley]

Have you checked the voltage at the socket to see what voltage is getting to the lights. If there was some corrosion visible you might have some further back from the sockets in another connection or in the wires that is not visible.

[Mopar1973Man]

Check the head light fuse? Located in the PDC...

[bh115577]

I have a full 12 volts at the passenger side plug with it unplugged from the light. Once I plug it into the light, it drops down by 4 or 5 volts at each wire. When I replaced the pigtails, I cut the harness back a few inches from the corroded connectors and didn't see any corrosion under the insulation.

 

Fuse is fine and the relay is ok as well.

[Mopar1973Man]

Remember there is 2 grounds and 1 positive to the stock head socket.

[bh115577]

Remember there is 2 grounds and 1 positive to the stock head socket.

 

There's one of my issues. I've got red, purple,and black. The manual says to check the z3 ground circuit but isn't clear on the location of the ground points.

 

Looking at the 2001 Ram manual on page 959, I'm guessing that the vt/wt wire is ground on low beam and the rd/or wire is ground on high.

[joecool911]

Not sure how to tell ya to fix it, but in my experience with dim lights it's almost always a ground issue.

[Mopar1973Man]

Yeah but here is the catch.

 

+12 Volts -> L & R Head Fuse -> L & R Headlight -> Dimmer Switch (switching grounds) -> Headlight Switch -> Ground

 

So typically if there is a dim light its a head light fuse because the ground circuit will back feed power to the blown fuse side. Fuse have been known to crack and not appear blown and the only way to test them is with a DVM. If it was a bad ground then both light would be dim being the head lights are switch off at the ground not the power.

[bh115577]

Yeah but here is the catch.

 

+12 Volts -> L & R Head Fuse -> L & R Headlight -> Dimmer Switch (switching grounds) -> Headlight Switch -> Ground

 

So typically if there is a dim light its a head light fuse because the ground circuit will back feed power to the blown fuse side. Fuse have been known to crack and not appear blown and the only way to test them is with a DVM. If it was a bad ground then both light would be dim being the head lights are switch off at the ground not the power.

 

That makes sense. I tested the fuses with my DVM but I'll check them again. I did notice that with the headlights on when I pulled the fuse for the right headlight nothing happened to either light, but when I pulled the fuse for the left headlight they both went out.

[Mopar1973Man]

Left headlight fuse is powering both light.

 

Right headlight fuse or circuit is dead. Pull the fuse and ohm it out and make sure its 0 ohms. Or test it on voltage and ground your black lead and touch the test pins on the fuse and check for voltage on both sides of the fuse. If power is on one side and not the other then the fuse is blown.

[Ilikeoldfords]

Try switching the fuses from one side to the other. If the problem follows, its the fuse then. On a side note, I didnt realize these trucks had a fuse for each side. Kinda cool and good to know.

[bh115577]

Checked the fuses again and found they were both good. Did find that there was 12 volts going through the fuse but not making good contact in the PDC connection on the way out to the headlight. Got it cleaned and tightened up and all is good now.

 

The backfeed thing burned me on this one. Lesson learned.

 

Thanks for the help.

[klcammie]

Great thread I've had the dim pass. side headlight, checked grounds and wires. Did not know about the fuse. Will check the fuse connections in PDC. Thanks. Always good info here.

[Mopar1973Man]

Remember gang the headlight ground is NOT under the hood but at the driver side kick panel being the last place it stops at is the headlight switch in the dash and goes right down to the kick panel.

[keagan M]

i had that same problem when i purchased my truck and my dad fixed the problem but it was something to do with a ground not working right and taking power from that light

[SecondGen]

My issue is a dim drivers light. If I pull the fuse for the passenger headlight I lose both. I’ve replaced both fuses and checked my connection on the bulb, even installed a new switch.. where might my issue be?

[Dieselfuture]

3 minutes ago, SecondGen said:

My issue is a dim drivers light. If I pull the fuse for the passenger headlight I lose both. I’ve replaced both fuses and checked my connection on the bulb, even installed a new switch.. where might my issue be?

I would double check all grounds under the hood in front of driver battery especialy and there is also a ground terminal block under driver side kick panel. 

[SecondGen]

I have taken the grounds off, cleaned them and put some bulb grease on them. Checked both fuses and have power flowing through both fuses. Now for what confuses me, if I pull the fuse to the drivers side nothing happens and both lights stay on (passenger side at full power and drivers still dim) but when I pulled the passenger headlight fuse I lost both headlights (the drivers one is the one I’m having problems with) but when I check with my test light I still have power to the drivers headlight plug but it won’t light the bulb.