Ford Repair Questions? Ask a Mechanic for Answers ASAP
Hi, I’m Chris. Welcome and thanks for asking your question!
With the headlights on does fuse 36 have power?
no, fuse 36 is not getting any power.
With the key on are both fuses 10 and 3 under the dash good and showing power?
yes, both fuses (10 and 3) are getting power readings on both sides of the fuse with the key on.
Pull the headlamp switch out of the dash, and turn the headlights on with the dimmer set to full intensity. What voltage do you get at the yellow/black and light blue/red wires?
i am able to check with the switch in the dash...
yellow/black wire: 0
light blue/red wire: 0
Was the key on when you checked the YE/BK wire, forgot to mention it?
ok, retried with key on,
light blue/red: 0
Thanks for doing that check, this indicates the headlamp/dimmer switch is faulty, it is getting power in but sending none out to the instrument illumination.
ok, that seems odd since the original switch had this problem and the new one i replaced it with today has the same issue. i also just noticed that the tail running lights are now not working (on van and trailer) and the brake and turn signal lights are working on van and trailer. those lights were working before the faulty switch was replaced earlier today.
This switch must of been damaged in the box if those wire tests were done correct, see the diagrams below.
i decided to check all fuses for power in the fuse box and found fuse 10 blown, which is odd because i swear it had power earlier when i checked it both sides. anyways, i replaced it and all lights are working properly now. thank you for your help, i really appreciate it.
Glad I could help, sometimes when you test things, you just have to double check them. Please take a moment to rate my response.