My 2002 truck is exhibiting the following lighting issues. Re-installed fuses, relays related to these areas with no impact. Looking for other ideas.

1.) Headlights/Running lights OFF: When brake is depressed (activating brake lights) the dash lights dim considerably. When turn signals are activated they work correctly but the running lights come on at a low level of intensity.

2.) Headlights/Running lights ON: Brake light activation has no impact on dash lights. Left turn signal operates correctly. Right turn signal will not cycle/blink. Rear license plate lights also flash when TS is activated.

Looking for help-thanks

 

I'd 1st check all grounds, make sure that they are good & checking wiring along the way.

How long has this been happening?

Does this sit outside? Have you had rain lately? IF yes to those ...then , Is there a damp spot on the floor on the drivers side? (mostly after a rain)

Is this truck recently "New to you"?

 

also possibly the light switch internals ........... multi function switch ( turn signal) can cause a variety of problems, but have not hear of some of these.

 

It's a grounding problem.

Pull both of the cabin kick panels off and inspect the cabin grounding studs. You'll probably find one of them badly corroded.

 

Truck has been in the family since new and always kept in garage/machine shed. Not sure how long the symptoms have been present since I don't drive it often. No rain/wet interiors so I'm going to work the grounding/earthing angle this weekend and see what happens. Might have to pull the turn signal relays as well.

Thanks!

 

I would first check grounds like mentioned earlier. Clean them while you're there and coat them in dielectric grease when you put them back together. I've diagnosed a few lighting issues before and wound up changing the multifunction switch (turn signal switch. Don't fire up the parts cannon though. Proper diagnosis is important.

 

Thanks for the inputs. I spent a couple of hrs this weekend checking/cleaning grounds, connectors, etc. Long story short found that the right rear turn signal, brake and ground wires had been stripped by mice. Should have looked there first but it seemed more complex. Damn rodents.