I may have a problem with the gizmo that turns on the daytime running lights (Canadian vehicles only).

At idle the lights dim and brighten rapidly - not like with the intake grid heater cycling. Voltage does NOT fluctuate.

All of my park lights quit sometimes. Front and back lights may stay off for 5 minutes or a half hour. This is when the headlights are on. No problems with the headlight switch and the dash lights function normally.

Could this be the sign of a relay or something associated with the daytime running lights?

If I can't figure this one out I will use the dash lights to control a relay - hot wiring the park and taillights. Any feedback.

I don't think this is exclusive to the diesel.

 

Hi Bill, the only symptom for a faulty daytime running light control that I know of is that your headlights won't shut off. Happened to a friends 1993 CTD and until she got a new one (dealer about $100) she would disconnect her battery. I don't know what relay ties into the control.
Andrew

 

Hmmm. My daytime running lights don't shut off when I acitvate the park brake.... since I got the truck years back. On startup they don't come on until the brake is released. They stay on till I turn off the key. I am about to look up the wiring diagram but I fear it may not cover Canadian setups.

Thanks for your reply.

 

Hey Bill this may provide a clew for you, dunno. My light switch fried some years ago along with the adjoining harness block terminal, so I wired in a toggle switch bypassing the orig switch, and cut the wires to the bulbs. These wires now trigger two relays, one for hi and one for lo beam. Works so well I've left it that way, but two intrigues remain. My DRLs work fine except one comes on bright and one has the proper reduced intensity!? They're off after I start but come on when I move. The park brake has no effect, but then neither does my park brake light come on, so I'd suspect the switch there. Another rainy day project. Sorry for so long but there may be something you can use given that our systems are likely about identical.

 

The more information the better. Our weather is making a change for the warmer so I may get at tracing this one down.