My 1999 Mercury Cougar, with a 2.5 liter V6, continues to have electrical problems despite a recently installed new battery andalternator.The only way to crank the car is to jump it, and after l remove the cables, it stutters, the lights to dim and it shuts off. Also, a recently installed $150 brake light switch is no longer working.A friend indicates a computer/sensor problem here. Anyone have any ideas?, ......Help In GA !!

you could have a major short, but l would think that the wire would burn up if that were the case. If the voltage reg is seperate from the alternator, replace that.

the cougar is had wire chafing problems. carefully inspect the wire from the battery to the alternator. This wire is hard to see in many places you might need to remove the right tire and fender well for a better visual. if this wire is chaffed/shorted your alternator will not charge the battery. good luck

We also have a 99 cougar, V6. Had similar problems. Turned out to be emmissions sensors, & also the ignition module. Also had several other electrical problems with it i.e. brakelight switch module, , alternator (which then fries the battery), dash lights, & check engine light. Ours also sounds like a tugboat horn when it idles We r currently unloading this car as a trade on a new mustang. l HIGHLY reccomend u do the same if possible. This car was definately a lemon. We bought ours used so we had no recourse from the manufacture.

PS did ur moonroof break yet? Everyone with a moonroof in a 99 seems to have the arms break on the moonroof at about 20K miles. Not a cheap fix, (about $1500-2000). We decided to just live without a moonroof.