Dim low beams

Is your 2001 with the daytime running lights or without? The wiring is substantially different.

If without, the 12 V power arrives at each bulb's common terminal, so any problem there would affect high and low beams.

The path to ground from the low beams passes through a junction connector (J4 / J5), another junction connector (J12 / J13), pins 17 to 16 of the headlight dimmer stalk, and another junction connector (J17) on the way to body ground point IG (in cabin, body sheet metal at the right of the dash, possibly visible with glove box removed).

From that ground point up to pin 16 of the dimmer stalk is, of course, common to high and low beams, so probably isn't your issue.

Wiring for the headlights with the daytime running light feature is ... different.

 

Take a voltage reading at the connector for high and low beams.
A bad ground is a common issue for headlamps that are dim. If they bulbs are good.
You could always run a jumper and ground wire to the light bulb and see if you get a good
bright bulb. If you do, then the bulb(s) is(are) good.
You can also jump the connector ground to the chassis and see if they are bright.

Try the simplist things first, because they are simple, and easy.

 

Keep in mind that these gen 1 lights (in the non-DRL version anyway) are supplied 12 V at the bulbs' common terminals, and the ground returns are what get switched to have high or low beam.

 

A Gen 1? I’m just a little incredulous, this being Gen 3 forum.

could the headlight lens be a factor; are they getting hazy from sitting in sunlight?