When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm lost on my truck right now. I have a 2004 f150 fx4 4x4. The other day I was driving with my heater on and headlights when I looked at the dash everything was really dim like the battery was dying. So I pulled over just to make sure all the cables were tight on the battery. When I got back in the truck the lights were still dim so I turned of my headlights and heater so the battery would die faster. When I did that all the dash lights brightened up and looked normal so I took off driving and it started getting chilling in the trick so I turn the heat on and the lights when back dim and the heater don't kick on. So when I got home I started messing with the truck. When I turn on wither the headlights or heater everything dims, the turn signal lights just stay on and the brights light just stays on. If I put the high beams on the brights light goes off lights it's opposite from what's really on. The doom lights turn off if they are on. But the second I turn off the headlights and heater it all goes back to normal. I've checked grounds, fuses, switched relays, switched battery and the power cable that goes to the fuse box. I'm lost right now and any help would be greatly appreciated!
I haven't, but I did pull the alternator wire off while it was running and when I hooked it back up the engine rev'd up like the alternator gave it more power. The truck starts, runs, and seems like it has plenty of power. My headlights don't dim or anything.
Agreed on the alternator. I had a similar issue with mine, if the headlights, heat, windshield wipers were all on, the battery light would kick on. Wouldn’t do it any other time. Got it checked and replaced, no issues since.
Isn't the dash lights supposed to dim when you turn on headlights?
Negative... The dash lights (instrument cluster) do not come on until the headlight switch is at least turned on to the parking lights. Brightness is controlled by dimmer switch. Usually only lighted displays like the radio will dim when the headlights are turned on.
Negative... The dash lights (instrument cluster) do not come on until the headlight switch is at least turned on to the parking lights. Brightness is controlled by dimmer switch. Usually only lighted displays like the radio will dim when the headlights are turned on.
Bad voltage regulator in the alternator.. very common problem in our trucks.. I suggest a motorcraft re-man due to the voltage regulator in the cheapo’s
Dash lights dimming
