You're right. If the high beams and the "flash-to-pass" feature both work, both parts of the head lamp switch are working. The low beam circuit leaves the multi-function switch on the violet / white wire and goes right to both head lamps, but the circuit goes through one of the joint connectors in the under-hood fuse box. That connector splits the circuit in half which will help narrow done the cause of the problem. There's a couple of ways of approaching this to verify the multi-function switch is defective. You'll need a voltmeter or test light for some tests.
The Security relay ties into the circuit at the joint connector. Pull that relay out and use a stretched out paper clip or piece of wire to jump terminals 30 and 87. If the low beams light up, everything is okay from that point on, and it looks like the multi-function switch is the problem, but lets check a little further first.
A different test involves measuring the voltage on pins 4, 5, 6, or 7 in the joint connector. There should be 12 volts there when the low beams are turned on. If there is not, again, suspect the multi-function switch. At that point, since it looks like the switch is defective, before you replace it, check for voltage right on the violet / white wire. If by some chance you have it there, we'll have to hunt down a break in the wire after that point. The definitive test for a defective switch would be to jumper the violet / white wire to the light green / black wire right at the connector. That will bypass the low beam half of the switch. If the low beam lights come on, you know everything else in the circuit is working and the switch must be replaced.
I'm using a '98 service manual, but I'm pretty sure this circuit is the same for a '97. My sad drawing shows the two terminals to connect in the Security relay socket, and the red line shows the four connected terminals in the joint connector. From what I can remember, you might not be able to get on the internal wires with your meter probe so you'll just have to ignore that part of the test.
Sunday, July 10th, 2011 AT 8:18 AM