Possible electrical problem

Hello guys.
I have a 98 taurus. I have the following problem.
I go to start the car, the car won't start the dashboard lights turn off and it acts like when your battery is dead or there is a bad connection. I disconect both battery cables and reconnect them and the car will start and run with no problems. 2 days later the same problem. I disconnect and reconnect the cables and it works fine again. It has done this for about a month.
I had the battery and alternator tested and they were both good. Checked fuses and they're both good.
Like I said before, when I turn the key the dashboard lights turn off even the radio resets sometimes. Another thing that happens is that the alarm system won't even respond, it won't unlock the doors when this happens. I can hear a relay trying to do something when I try to turn the alarm off with the remote.

I hope I explained my problem clearly.

Thanks for any help.

Sounds like ground somewhere, Check ground to the body, battery cables, ground to dash, key, all need to be ruled out. There is no corrosion on the battery connections? Check it for blackening of the post and inside the clamps if lead, that will limit current. Do the other lights remain operative after the failed start/no dash lights, like the dome, headlights, brake, signal? Take a continuity tester and check your dash area for ground after the lights go out to see if dash area has a good ground. My last thought is you may have a weak underhood relay or fuse that controls the affected components. Good luck Let us know your pain or gain.

Also, do you have molded battery cables (OEM style) or the temporary repair ends that allow corrosion to wick into the cable and cause a bad connection?

If I understand your symptoms correctly, you don't experience the bulb test in the instrument cluster when you turn the key to run/start and there is no clicking when trying to start the car? If that's correct, you couls also have a bad igntion switch (not the ignition key cylinder switch, but the actual ignition switch). Maybe next time rather than disconnecting the battery, try cycling the key off, then tapping/beating on the steering column a bit and trying to start the engine again. Just don't let co-workers see you beating on your car. They may call the cops thinking you are at risk for road rage.

-Rod

BE VERY VERY CAREFUL WHEN GETTING INTO THE ELECTRICAL BECAUSE YOU WILL WASTE ALOT OF MONEY, REASON WHY: MINE DID THE SAME THEN IT STARTED NOT WANTING TO START ONLY IN COLD WEATHER THEN STARTED SHOOTING OFF CRAZY CODES LIKE THE WATER WAS LOW BAD O2 SENSOR NO OIL ENGINE TEMP SENSOR CRANK POSITION SENSOR. THE WHOLE TIME A CRACK IN THE MOTHERBOARD IN THE COMPUTER. BOUGHT ONE FOR 100.00 FIXED IT ALL. FOR TWO WEEKS WE STARTED IT WITH STARTER FLUID, THEN THAT QUIT WORKING SO THE MECHANIC HAD IT FOR THREE WEEKS COULDNT FIGURE IT OUT SO I TOOK A SHOT IN THE DARK AND BOUGHT ONE AND WELL PROBLEM SOLVED CHECK THE INPUTS TO THE COMPUTER AND OUT OF THE COMPUTER.:banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: