Seem to continually have problems with my 99' f150. Yes, she getting old (240k) but I think she has much life in her yet! Started a few years back when I pulled the dash forward to replace a heater core- lost the low beams when dash and core was replaced and put back. Last year lost heater-replaced the control panel with a used part pulled from another truck. I thought it worked when I replaced it but maybe I was wrong. The other controls work on the panel(fan speed and blend) I did notice the blend door was broken when I replaced heater core, I glued the parts back together and worked just fine. Recently I lost my headlights all together, but my running lights work and bulbs and fuses are fine. So here is the list, in order:
1)No low beams- could it be the signal tree on the column?
2)No heater- could it be a temp blend door?
3)No headlights,fog lights don't work either- could it need a new switch?

I'm hoping its not some electrical wires shorting thats slowly being pinched one by one!

Any suggestions?

 

Check electrical issues for proper grounding. Just looking isn't enough. Use a VOM set to ohms to perform ground checks. A good ground should indicate near "zero" or 0 ohms across the probes. Pull dash again and look for pinched or pulled wiring.
Keep us up to date with your findings, OK? DIY