2000 ram 2500 5.9 v8. I had the left (driver) fender/inner fender off for a while (like a year), and put on a replacement just in the last couple of weeks... getting it ready to drive again for winter.. Everything worked before tearing it down, and it seemed all was ok except for the left turn signal didn't light up, and parking light was ok. Figure it was a bulb issue, so we put in a new bulb, a 4157. No parking light after that. Tried cleaning the contacts, and still couldn't get the parking light to work... then we tried the turn signal. It would cycle quickly and flash the front lamp, but I could hear a snapping sound and feel the snap vibration on the cruise control module that is bolted to the front of the battery tray!? Now the right turn signal lights up constantly on the dash when the battery is connected, and I still don't have parking lights on the left side.

I checked for bad ground, pinched wire, etc... can't find anything wrong. Anyone able to offer any clues to help diagnose? The right turnsignal dash light with the left side issue, has me perplexed.

 

Follow the harness that runs along the drivers fender, I suspect you pinched it somewhere.

 

Yeah, after sleeping on it, I think its possible that the battery tray is putting compression on the main harness. I thought for sure that it routes under the tray.... maybe it doesn't, or maybe the fender I replaced didn't have the same provisions (space dimples) for the harness? Not sure... I'll have to strip that bundle down and see what is going on, probably later this week... I'm SOOO close to having this thing back on the road....

 

Pulled the battery tray, unhooked the cruise control's power cable, and looked over the cabling that goes under the battery tray. Nothing I could see wrong with the wiring, but I didn't unwrap it all, there is a lot of tape to cut.

So I decide I need more tests, here are the results:

Parking lights off, 4 ways work like you'd expect - but the left front bulb is only flashing the less bright portion of the bulb (outer most resistor). Rear ones doing what you'd expect.
Parking lights on, the turn signal indicators in the instrument cluster come on solid, neither front parking light works, but rears are fine..
Parking lights on, 4 ways work like you'd expect, but the left front bulb is only flashing the less bright portion of the bulb (outer most resistor). Rear ones doing what you'd expect.

Key on (have to to get the turn signals to operate)
Pull down on the switch, left turn signal flashes (same wrong portion of the bulb), but flashes really fast. Pull up on the switch, right tunr signal flashes really fast.

So now I get curious about the initial condition that had me thinking to replace the left front bulb.... I take the old one in and apply 12volts, and the bulb seems fine... Dang it, I assumed it was a bulb and that wasn't the initial problem. Also I had checked the lights BEFORE bolting down the battery tray, so now I'm thinking something went wrong while it was sitting around and I didn't crush a pair of wires together with the battery tray.

What happens when the multifunction switch goes bad?

 

Are the bulbs installed wrong?

Do both turn signal indicators in the dash come on with the parking lights?

 

There doesn't seem to be a wrong way to install the bulbs, I flipped them a couple of times, work the same every time.

Yes both turn signal indicators on the dash come on with the parking lights.

 

Are the grounds for both sides hooked up? Is it a GOOD ground? Are there the correct bulbs installed? The bulbs should have one of the 'lugs' on the brass part higher than the other, and the slots they fit into should have the divits that turn into at different depths as well. having the bulb 180 out, should lite a different filament in the bulb.... does it not happen that way?

Edit: Looking at the 01 FSM, it appears those are two wire connectors? So, single filament bulbs??

 

No, its 3 wire with two filaments. Google "3157 socket pinout", you'll see why the orientation makes no difference. Didn't have a shot at working on it tonight....

 

Hhmmm.... that's weird. The wiring diagrams only show two wires...... wonder if they just left the turn signal circuit out of the parking light diagram......

 

I grabbed a multi-function switch out of the jyard from a donor that just arrived and had a recent inspection... same thing, so I've eliminated that piece. Also eyeballed the wires in the column, look ok. The parking/turn signal sockets look a bit suspect up front from corrosion, so I grabbed a couple of new replacements tonight. I'll splice those in and see if the problem persists. Else next step will be to grab a full harness out of the yard, including fuse block, and see what happens then... :-/ Dang it, running out of weather fast !