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When you turn the key to the on position does the yellow check engine light illuminate? Do all the normal warning lights illuminate? Do you have a code reader to see if it will communicate with the engine control computer and pull any diagnostic trouble codes?
Based on your description it sounds like you may have disabled the charging system or blown a fuse this could also cause the check engine light to come on and when the battery gets low it will shut the vehicle off. The vehicle skid control light will come on by default whenever the check engine light comes on. When you get the code numbers post them back here and I can give you more detail on what they mean and possibly where to go with this.
Time off for the holidays did you get this problem resolved yet? If you clear these codes do they continue to keep coming right back? Have you considered eliminating the wiring for the lights that you installed to see if anything got tied to the wrong wire?