I need electrical help dashboard wiring

[HarveyP]

Our 94 Holiday Rambler Endeavor LE DP on an Oshkosh chassis has a problem. The cigarette lighter gives 12.5 volts, until I turn the headlights or even parking lights on. Then the voltage drops to around 2 volts if the instrument panel lights are turned up bright, and will increase to 5 or 6 volts if the panel lights are dimmed by turning the headlight switch knob. This also affects the power mirrors. My local auto parts guy who also does mechanic work says I have a ground problem. I disconnected both headlights, front park lights and both taillights, same result at the dash. Can anyone offer a suggestion? Thanks, Harvey

[HarveyP]

Our 94 Holiday Rambler Endeavor LE DP on an Oshkosh chassis has a problem. The cigarette lighter gives 12.5 volts, until I turn the headlights or even parking lights on. Then the voltage drops to around 2 volts if the instrument panel lights are turned up bright, and will increase to 5 or 6 volts if the panel lights are dimmed by turning the headlight switch knob. This also affects the power mirrors. My local auto parts guy who also does mechanic work says I have a ground problem. I disconnected both headlights, front park lights and both taillights, same result at the dash. Can anyone offer a suggestion? Thanks, Harvey

[Wallaby Dan]

Hi Harvey, It has to be a ground that is disconnected or corroded,under the dash.It probobly is in a group screwed down on the steering column under the dash. Most of the motorhomes have a bracket under the dash that gives strength to the column and it is the ground point for most of the wiring systems. Good luck and let us know how it works out for you,Dan

[RV Wizard]

Attach a 10 guage wire to a known good ground and run it to the dash area and bond it to the metal framing as Capt. Dan has indicated and it should correct the problem. Let us know if not.

[HarveyP]

Hi, I tore the steering column apart. Lots of wires, but no obvious ground connections. To make the problem more strange, if the park lights are turned on, and then the mirror-defroster-heater switch is turned on, my Allison transmission indicator panel lights up even though the key is not even in the ignition lock. Also, the behind-the-panel lights come on. Those are the ones that shine through engraved letters near the switches so you can read the function at night. This is the only time those lights will come on bright enough to see. Mike, I would gladly run a new ground wire if I knew where to connect it at the wiring end. There are no obvious places to connect to a number of ground wires. I am hoping the mirror defroster switch will be a clue to someone who knows more about electrical troubleshooting than me. Any suggestions? Thanks, Harvey

[school man]

Have you checked all the grounds for the running lights.Sounds like a bad ground in the light circuit.When a ground opens up with a duel filament bulb,voltage feeds across both elements of the bulb and back to the dash.Your ground problem may not be around the dash but behind one of the lamps.Taking out the lamps as you did may show up the ground problem.Do the lights come on weak,running ,turn,orparking, both at the same time.That would show an open ground,might look at it at night.Do the lights come on bright,running,parking.Keep us posted .Fixed an older winnie with about same problem and turned out to be a bad ground on one of rear tail lights. MIKE

[adj]

You should check the wires running from your lights switch.
One or more of those wires will terminate at a ground stud. Ensure that all ground wires are tight at the stud. Also, inspect the individual wires for frayed and loose terminations.

If possible, wiggle individual ground wires to see if it affects the indications you are getting.

[HarveyP]

Thank you to everyone! I did check every light ground and removed every lightbulb one by one. Nothing! I finally added a new ground to the cigarette lighter and attached it to the existing ground wire with a splice connector. That did the trick and everything seems to be performing as designed. My thanks to all of you who read and contribute to this awesome forum, HarveyP

[Joe-K]

Seems like ground problems are the root of all evil on RV's. Glad you found the problem.

[Wallaby Dan]

Good job HarveyP!!!