95 suburban 4wd and abs problem

I have a 95 suburban K1500 4wd with 182,000 miles on it. I went to trade it in recently and dealer didn't want to give me much for it because abs light was on (I knew this) and 4wd didn't work (I didn't know this). I thought the 4wd problem might be the actuator but on replacement, it still didn't work. I then found that when 4wd lever is engaged, no lights came on inside vehicle indicating it was on, but one line to actuator did become hot. I then started thinking that the abs problem could cause the 4wd to not work. Is that possible? I noticed that there is a wire to 4wd from abs.

I then found out that the ABS codes were 26, 27, 12, 25, and 68. 25, 26, and 27 codes indicated left front wheel sensor. 12 indicated 2wd without brakes applied and 68 indicated motor connector. Any suggestions on this?

Welcome to AF. I'd do a full abs scan and look at wheel speed sensor inputs to verify the sensor, this can cause a multitude of false codes, replace the sensor and go from there.