I need some help here please. I got off from work this morning at 6 AM and started my 1999 f-150 4x4 4.6 v-8 everything looked fine dash lights were on tail lights everything. Suddenly the dash lights go out so I check the dimmer **** it seems OK but no changes the lights are still out. Well I drive 5 miles to the house and turn off the head lights and they will not turn off. So I get out and check the tail lights and they are off even with the switch turned on they are still off. Any suggestions please

Thanks in advance Mike

 

Sounds like the switch has gone bad. To test it, take it out and ohm it by moving the switch on and off.

 

Well after reading up some more on the forums I went out and replaced the neg lead back to the battery ( thats how I turned the lights off when I got home ) and the lights stayed off ( OK thats a good thing ) I checked the F6 fuse under the hood. It is a 15 amp and it was blown. I replaced it and it blew that one also. Increased the fuse to 20 and it also blew. OK I have a short some where no doubt. I took the switch out and checked for loose wiring did not find any that was noticeable. I increased the fuse to 25 amps just to do a quick test, the instrument lights came on , the head light alarm came on, but the tail lights did not come on. Wire was starting to get warm so I turned everything off and replaced the blown 15 amp fuse back in the socket just so I would not make the mistake of putting a higher amp fuse in the space once the problem is corrected.

Now for some reason the wiring at the switch became very warm when I tested with the 25 amp fuse. so I'm guessing it is a bad switch.
What do you guys think.

Mike

 

OK I took out my Haynes manual that I forgot I had and took the switch out so I could run a check with my meter. In the off position the switch is showing good, and in the on position the switch is showing good also. I checked the voltage coming out of the with switch with a higher than rated fuse in line and the voltage is 9.55 dc and the wiring is also still getting very warm. any Ideas where to start looking for the short?


Thanks
Mike

 

Sounds like you have a short circuit to ground in your parking/running lamp circuit.

Steve