Erik Wilson

My mechanic and I have been running in circles trying to figure out what I think are two separate but possibly related issues. 1) Head lights go up and illuminate but they won't go down, not at least all the time (every once in a blue moon the will go down once) and 2)No taillights or reverse lights.

Work/Diagnostics thus far:

• All ground points inspected, cleaned and restored.
• Replaced head light relay as well as all other light-related relays
• Replaced all fuses
• Have jumped out the Bulb Control Unit per multiple threads (We have never had a bulb out light in the dash anyway. The BCU appears to have been wet at some point and hand multiple areas of oxidation)
• Have replaced all the rear light bulbs with matching, new OEM spec bulbs, nothing fancy)
• Have replaced the headlight dash switch
• Removed the rear bumper cover and repaired any damaged connections on the wiring harnesses for the rear light assemblies.

We have also removed the wiring harness from the head light switch and applied 12V to each terminal and have forced the taillight and marker lights to come on as well as the license plate light so we know there are no breaks in the wires between the switch and the bulbs.

The blinkers work front and rear.

The head light work and go up, but they will not go down. When we installed the new head light switch they went up and down one time. When we cycled the lights again, they stayed up.

I am at a loss and am hoping someone here has some idea what we are over looking.

Thanks in advance for any help or advise offered.

Erik

docmirror

Since it's intermittent, I can suggest looking at the drive pick for the relay power to the folding headlamp motor. The relay pic signal comes from the motor area itself. If you locate the motor, there will be a connector on it. The wires on the connector will be labelled 30, 30B, 86, 56 and there is a ground wire which may be brown and not labelled. The wires you are interested in are the 30B, 86, and 56 wires. Put the red test lead on 86 of the motor housing and the black lead on 56 of the motor housing connector. With the motor up, you should read open circuit. Move the black lead to 30B, and again should read open circuit. Now, move the motor so the lights are down fully. Repeat the meter readings above. Both should be low resistance, below 3 ohms. Note carefully the polarity as there are diodes in the circuit and will only show conductance in one direction.

make the measurements and let us know what the readings are. You can open the unit, and clean the contacts and the wipers but be careful in there.

[I had to edit to indicate that the readings should be taken not from the wire loom, but from the pins on the motor/switch housing where the pins lead into the motor/connector.]