1999 Chevy Malibu OBD errors

My 1999 Chevy Malibu is a v6, automatic transmission with approx 97000 miles on it. Recently (just this winter) the brake and abs lights will come on together at random times (seems like more often when the engine is cold), and while the lights are on, the brakes work fine including ABS. When the lights come on however, most of the electronics on my console stop working. The dash instrumentation is fine, and the stereo works, but the fans, heat, defroster, door locks, power windows all do not work until the lights go off (usually a minute or two).

Even more recently (in the last 2 weeks), the check engine light has been coming on and going off intermittently. I have an OBD reader and have retrieved the following errors:
P0135 (O2 Sensor heater circuit malfunction)
P1665 (Driver 3 Line 5)
P1676 (Driver 4 Line 6)

My questions are as follows:
1. Are these error codes related to the abs/brake light issue?
2. Is this something I might be able to fix on my own?
3. Could this have been caused when a new stereo was installed? (I just had one installed shortly before the problem started)

Thank you for any help you can give me. P1665 is Evaporative Emission (EVAP) Vent Solenoid Control Circuit
P1676 is Evaporative Emission (EVAP) Purge Solenoid Control Circuit

There is a ERLS 10A fuse in the underhood junction box that protects the circuits for the EVAP soleniods and the post catalytic O2 sensor heater. More than likely the fuse is blown. As to what is causing the fuse to blow is going to take some diagnosis.

As for the dash and lights there was a previous post that had some common traits even though they are different vehicles. Maybe you could ask him to see what their solution was.
 

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I am having the exact same problem you described. I have a 99 Malibu V6, and it has been displaying the same Check Engine Codes, as well as the other issues you described. Were you able to figure out what went wrong and how to fix it? replace the ignition switch,this is a common n body problem.