2nd Gen Non-Engine/Transmission Odd Left Turn Signal Problem Please Help

[KBrennan]

I am at my whits end. I have a 1999 Ram 2500 Diesel. Here is what the problem:
Left Turn Signal Hyper flashes. The front Left bulb flashes but it is the parking light element that flashes
Right turn signal no issues, works perfect.
Left Parking light does not come on when lights are turned on but the left turn signal will glow steady if the left turn signal or hazards are not on.
Right parking lights are good
The speed (cruise) control servo will click on and off and so will the hood work light. when the left turn signal is turned on.
If I remove the Left front Parking/Turn bulb the issue with the indicator coming on steady with the parking and or head lights is gone. Of course it still hyper flashes since there is no bulb
I have replaced all the bulbs and I have swapped bulbs around with no change in symptoms

There is no visible damage tot he wires. I have pulled the driver's side battery and tray and looked all over. Nothing stands out.

Please help, I have a trip coming up in a few weeks and need my truck.

 

[B.G. Smith]

The problem with the rurn signal is the socket that the left front turn signal bulb fits in has lost ground. The other odddity of the cruise light flashing instead of the turn is possibly also loss of ground related. bg

 

[petersonj]

I think you may have a ground problem in the left front area of the truck. When a ground circuit has high resistance, very little or no current can flow through that part of the circuit. The turn signal light filament and the park light filament share the same bulb. The filaments have separate inputs, but they share the same ground connection. I think the shared ground connection is good, but the connection has been lost somewhere between this location and the battery.

Consequently, the current generated from the left turn signal switch to operate left front turn signal cannot complete its normal path after passing through the turn signal bulb filament. The current will back feed through the park bulb filament (because the two bulbs share a common ground connection) to find another source of ground, typically the other park lights . Because the park filament is of lower wattage than the turn signal filament, two things happen:

1. The park filament will light (not enough current passing through the turn signal filament to make it light, but enough back-feeding through the park filament to make it light).

2. The flasher will cycle rapidly as it should do because it detected the low overall current flow.

A simple electrical test will tell you if this is the culprit. You will need to remove the left headlight assembly to access the park/turn signal bulb. Using a suitable jumper wire, tap into the grounded side of the park/turn signal bulb. The bulb must remain electrically connected to perform this test. Turn on the ignition switch and activate the left turn signal. At this time touch the other end of the jumper wire to a battery ground terminal. If the problem corrects itself instantly, you now have only to find the source of the poor ground connection. It is likely to be a poor or missing connection between the body and the frame near the area you are working at.

Faulty grounds can cause the most unusual symptoms making an electrical problem very difficult to diagnose.

John

 

[KBrennan]

Looking at the generic wiring diagram the left and right turn signal uses the same grounding spot as does the head lights. However the left also passes through a ground joint connector (C123) I think if I can find this C123 then that is the place to start. Checking continuity between this connector and the bulb will tell me if this wire is the culprit. Question is, does anyone know where C123 Ground Joint is? For an interim fix could I put in a jumper from the ground wire at the bulb connector straight to chassis ground?

 

[seafish]

Actually the best place to start would be the bulb base and check for corrosion between the terminals there (if you have not done so already), then work your way back.

 

[KBrennan]

Well I found C123. It is a junction plug under the driver's side battery tray.It was for the most part clean but did have a little white residue on the top of it. Looked like battery acid. Cleaned it and puled it apart. Inside it was spotless. I rang the wire out from the bulb socket to the plug and it read 1K ohms. I installed a jumper from the bulb directly to ground and the problem went a way. I am going to leave it like it is as it is to much of a PIA to pull one wire out of the loom to replace it.

Thanks Everyone that had helpful suggestions.

 

[B.G. Smith]

Glad you got it worked out, also thanks for the followup on solution. That stuff can be a PIA sometimes. bg