My blower seems to work ok on all speeds,my heater works fine,but when i turn selector switch to the right on air out dash vent positiion my headlights and interior lights dim.When i continue to change to the right it stays the same as first position or dash vents.My blower resistor seems ok. Thanks for any suggestions.

 

Usually when lights dim when something is turned on , signifies there is an excessive current drain or a poor connection where the required current isn't available and the circuit voltage drops. When that happens the lights can dim . A good start would be to confirm all good ground connections and power supply connections also. The next step would be to measure the current drain when that particular function is selected. Something in the circuit is pulling more current than it should or it could be a high resistance connection. If a motor is used to position certain doors in the ventilating system and it is either stuck or jammed it could cause the lights to dim.

 

I just installed a new blower motor resistor.My blend door actuator seems fine.I have now got my whole switch panel out for my climate control.My red plug in,or top one,when i plug it in my headlights dim but i just realized today that the more speed i increase to my blower the dimmer my lights get. Am i looking at a blower motor problem or the switch .Since as long as i have the climate control on one of the settings besides off my lights do dim. So my lights dim from my blower speed switch and sometimes from my climate control switch. Any ideas would be greatly appreciatted. My van was built in Canada in may 1997 and i bought it as a 98.This vehicle manufacture date seems to be right in the middle of the buyouts. I don't know why since i can't seem to keep ahead of the repairs.I usually change my own oil and also do minor problems.The ford dealership never contacks me for anything.

 

There are some things you can check.You are chasing the blower system when it may not be the cause. Check the power supply to the fuse block. Check from the battery positive supply to the fuse block then to the lights. I believe the load of the blower motor is causing the entire system to operate on a lower voltage and the lights are just displaying the problem. Look for corroded or rusted connections where the fuses go especially if the windshield has been replaced sometime in the past. They leak and cause all kinds of problems that many times are caused by poor connections where the fuses are.