Before anything else. Check if your alternator is charging correctly. Clean battery cables both positive and negative. Clean battery end and other end as well - by that I mean removing bolts and clean with emery/sand paper or steel brush. Both cable and contact surface should be cleaned. These vehicles are sensitive to batt volt and current. You must be aware that there is a chance the vehicle will lock itself upon connecting the battery. So before taking off the battery, unlock and open both front doors. As per workshop manual, the last security status will be applied upon reconnection of battery. But this is sometimes not the case. Your remote needs synchronization when battery is connected. This procedure is in the owners manual. After the procedure, check if lights work. This may also fix your sluggish engine.
All electrical switches passes through the BECM - this is the computer under the right hand seat. My guess is that your BECM has a problem. You can verify this by going into a shop with auto diagnostics:T4(dealer), OMNI, AUTOLOGIC or ROVACOM/FAULTMATE have them switch lights on via diagnostic tool, have the switch response checked as well. If external lights work using diagnostics, its you switch. If the problem should be in the BECM, find a shop that repairs ECUs/ECMs, they could probably fix it. An alternative is to get a used BECM and have a shop reprogram (using aforementioned diagnostic tools) security,remote and milage. A final note, feel the floor rug/carpet front right hand seat - if wet, have your heater fixed or bypassed. And have the aircon drainage pipe cleaned as well.
MannyG, March 2008
