Those nasty alternator blues

Just put a new alternator in the 93 xfi. Fully charged battery before putting it in. Now when I drive, especially when its cold (the car and outside), you can see the lights dim, then come back to full brightness. This happens most when first driving. After awhile it seems the cycle isn't as frequent. I have checked the battery cable connections, the connections at the fuse block under the hood, the cable from the alternator to the fuse block, the cable from the fuse block to the battery positive post (both have very little resistance according to my multimeter).
The odd part is that the battery light on the instrument panel doesn't light when the lights go dim. It does light when the key is turned to on, before starting the engine.
HELP PLEASE!

is the belt tight enough? if its slipping it can cause that

Try this(what I did). Run an amplifer cable(8ga) from the charging post of the alternator, straight to the positive terminal of the battery. I would suggest a 60a in-line fuse, but it really isn't that necessary. See if that cures your woes. The wires that suzuki put in those are really crappy, and are prone to corrosion in the wire's jacket, and prone to breaking. Also, check to see that you have a decent ground line coming from the drivers side fender well to the - battery terminal. I would suggest an 8ga there too. I run 4ga myself.

http://img429.imageshack.us/img429/9141/photo0821050029cw.jpg

Try this(what I did). Run an amplifer cable(8ga) from the charging post of the alternator, straight to the positive terminal of the battery. I would suggest a 60a in-line fuse, but it really isn't that necessary. See if that cures your woes. The wires that suzuki put in those are really crappy, and are prone to corrosion in the wire's jacket, and prone to breaking. Also, check to see that you have a decent ground line coming from the drivers side fender well to the - battery terminal. I would suggest an 8ga there too. I run 4ga myself.

http://img429.imageshack.us/img429/9141/photo0821050029cw.jpg
Thats what I did, and I think that fixed it. I didn't bother with the fuse, I had a hunk of 8 gauge wire that I used. Nice clean engine compartment on your Geo! and thanks for the tip.