Hey guys,

Just a real quick bit about my truck - it's a 1991 F-250 with a 460 7.5L. About 2 years ago, I had some cab lights installed and wired directly to my headlight switch. Last year, I had a Western Snow Plow professionally installed. Here's the problem - when my plow is NOT hooked up, my headlights are very dim and the bright light indicator stays on. When my plow IS hooked up, lights on the plow are just fine and the bright light indicator only comes on when my brights are on.

I have cleaned up all the grounds on the battery and all the other ones I can find for the headlights. Is it possible that my headlight switch is bad? Thanks in advance!

JR

 

You may have the wrong head lamp bulbs. I found out the hard way when I swapped some blubs from a 92 F150 in to my 89 F250. The bulb's filiments are diffrent with how they are grounded(the high beam and ground are switched). I had no real change in high to low beams and the highbeam indicator was always on when the headlamps were on. The head lamps were grounding through the highbeam indicator's lamp!

As for working properly with the plow attached, probly a grounding issue or is there a lighting system installed with the plow?

 

I doubt it is the wrong headlight - I haven't had this issue until recently and I haven't changed the headlights since I've owned the truck.

As for the plow, there is an adapter that the truck headlight plugs into as the truck side wiring for the plow stays that way with/without the plow hooked up. So basically the truck headlight wiring plugs into an adapter, that then is wired to the plow hookup and to the truck battery.

I'm wondering if the truck headlight switch is overloaded with the cab lights and plow hookup.

I'm really lost here...I'm not sure which other grounds I can check to see what's going on.

 

sounds like you have a bad relay or two in the plow harness.the problem didn't happen instantly when the plow harness was installed was it? this is something that happened over time,after the installation?
the reason why the plow lights work nice and bright is because they do not load the switch.they work off relays.somethings up with the bright light indicator "glowing" though.
the reason why the truck lights are dim,is because they do load the switch and the wires are too small to support the load.there is an article here on how to install some relays (pre- your plows harness,so that that way,your truck lights run off relays too.)

 

I'm not sure if it happen when the plow was installed because I got the plow installed in December 2013 and didn't take it off the truck until April 2014 when all the snow was done. I noticed the dim lights and bright light indicator in the summer of this year.

Do you know where these relays are located? I'll try and take some me pics of the set up tomorrow and upload them.

 

Anyway you could post the link for that article? Thanks for your post, it has been very informative and helpful!

 

Whiter Whites, Brighter Brights - Ford Trucks